Omeprazole, commonly referred to as an acid- or proton-pump inhibitor, is a gastric antisecretory agent.1, 352, 353, 354, 355, 356
Omeprazole immediate- and delayed-release capsules, omeprazole immediate-release oral suspension, and omeprazole magnesium delayed-release oral suspension are used in adults for the short-term treatment of active duodenal ulcer.1, 352, 354, 355
Omeprazole delayed-release capsules and omeprazole magnesium delayed-release oral suspension are used in combination with clarithromycin and amoxicillin (triple therapy) for the treatment of Helicobacter pylori ( H. pylori ) infection and duodenal ulcer disease (active or up to 1-year history) to eradicate H. pylori in adults.1, 352 A co-packaged product containing delayed-release omeprazole capsules, clarithromycin tablets, and amoxicillin capsules (Omeclamox®-Pak) is also used for this indication.356 Omeprazole delayed-release capsules and omeprazole magnesium delayed-release oral suspension are also used in combination with clarithromycin (dual therapy) in adults for the treatment of H. pylori infection and duodenal ulcer disease to eradicate H. pylori .1, 352 Omeprazole also has been used in other multiple-drug regimens† for the treatment of H. pylori infection associated with peptic ulcer disease.5031
Omeprazole magnesium is available in a fixed combination with amoxicillin and rifabutin (Talicia®) for the treatment of H. pylori infection in adults.359 Consult the prescribing information for more details about the use of this fixed-combination product.359
In controlled studies in patients with endoscopically confirmed duodenal ulcers, reported rates of ulcer healing for omeprazole were substantially higher than those for placebo.1, 6, 352, 354, 355 In a multicenter, double-blind study in patients with endoscopically confirmed duodenal ulcer, reported rates of ulcer healing for an oral omeprazole dosage of 20 mg each morning or placebo were 41 or 13%, respectively, at 2 weeks and 75 or 27%, respectively, at 4 weeks.1, 6, 352, 354, 355 Omeprazole also produced greater reductions in daytime and nocturnal pain and antacid consumption than did placebo, with complete relief of pain in most patients usually occurring within 4 weeks after initiation of omeprazole therapy.1, 6, 352, 354, 355
In a multicenter, controlled study in patients with endoscopically confirmed duodenal ulcers, 42 or 34% of ulcers were healed following oral administration of omeprazole 20 mg each morning or ranitidine 150 mg twice daily, respectively, for 2 weeks and 82 or 63%, respectively, were healed after 4 weeks of therapy.1, 352, 354, 355 In another multicenter, controlled study in patients with endoscopically confirmed duodenal ulcers, ulcer healing occurred faster in patients given omeprazole 20 or 40 mg daily compared with patients given ranitidine 150 mg twice daily.1, 9, 352, 354, 355 Ulcer healing rates averaged 83 or 53% at 2 weeks, 97-100 or 82% at 4 weeks, and 100 or 94% at 8 weeks with the omeprazole regimens or ranitidine 150 mg twice daily, respectively.1, 9, 352, 354, 355
Most patients with duodenal ulcer respond to omeprazole therapy during the initial 4-week course of therapy; an additional 4 weeks of therapy may be necessary for healing in some patients.1, 352, 354, 355
Existing literature in patients with H. pylori infection and duodenal ulcer disease has shown that the addition of omeprazole to treatment with clarithromycin plus amoxicillin (triple therapy) was more effective at eradicating H. pylori than treatment with clarithromycin plus amoxicillin (without omeprazole);1, 352, 355 similarly, dual therapy with omeprazole plus clarithromycin was more effective at eradicating H. pylori than monotherapy with clarithromycin or omeprazole alone.1, 352 However, current guidelines from the American College of Gastroenterology (ACG) do not recommend dual or triple therapy regimens with clarithromycin and a proton-pump inhibitor (PPI) as a first-line treatment due to the increasing prevalence of clarithromycin resistance in clinical practice.5031
The ACG published an updated guideline on the treatment of H. pylori infection in 2024.5031 In treatment-naïve patients, optimized bismuth quadruple therapy (consisting of a standard-dose PPI, bismuth subcitrate or subsalicylate, tetracycline, and metronidazole) is recommended first-line; other suggested first-line regimens include rifabutin triple therapy (omeprazole, amoxicillin, and rifabutin [Talicia®]), vonoprazan plus amoxicillin, or vonoprazan plus clarithromycin plus amoxicillin.5031 Optimized bismuth quadruple therapy is also suggested for treatment-experienced patients with persistent H. pylori infection who have not previously received such therapy; rifabutin triple therapy is suggested in patients with persistent infection who have previously been treated with bismuth quadruple therapy.5031 Regimens containing clarithromycin and levofloxacin should be avoided in the absence of demonstrated susceptibility to macrolides and quinolones, respectively.5031 Potassium-competitive acid blocker- (PCAB; vonoprazan) or PPI-clarithromycin triple therapy is suggested for treatment-experienced patients with persistent infection that is confirmed to be susceptible to clarithromycin.5031
Omeprazole immediate- and delayed-release capsules, omeprazole immediate-release oral suspension, omeprazole kit for oral suspension (Konvomep®), and omeprazole magnesium delayed-release oral suspension are used in adults for the short-term (4—8 weeks' duration) treatment of active benign gastric ulcer.1, 352, 353, 354, 355
In controlled studies in patients with endoscopically confirmed gastric ulcers, reported rates of ulcer healing with omeprazole therapy were substantially higher than those with placebo.1, 352, 353, 354, 355 In a multicenter, double-blind study in patients with endoscopically confirmed gastric ulcer, reported rates of ulcer healing with omeprazole 20 or 40 mg daily or placebo were 48, 56, or 31%, respectively, at 4 weeks and 75, 83, or 48%, respectively, at 8 weeks.1, 352, 353, 354, 355 In patients with an ulcer larger than 1 cm in size, the percentage of patients with healed ulcers at 8 weeks was greater with the 40-mg dosage than with the 20-mg dosage of omeprazole.1, 352, 353, 354, 355 Otherwise, for patients with smaller ulcers, no difference in ulcer healing rates between the 40- and 20-mg dosages was observed.1, 352, 353, 354, 355
In a multicenter, comparative study in patients with endoscopically confirmed gastric ulcer, ulcer healing occurred at 4 weeks in 64 or 78% of patients receiving omeprazole 20 or 40 mg daily, respectively, compared with 56% of those receiving ranitidine 150 mg twice daily; at 8 weeks, 82, 91, or 78% of patients receiving omeprazole 20 mg daily, omeprazole 40 mg daily, or ranitidine 150 mg twice daily, respectively, had healed ulcers.1, 352, 353, 354, 355
Omeprazole magnesium delayed-release oral suspension is used in adults and children ≥1 year of age, omeprazole delayed-release capsules are used in adults and children ≥2 years of age, and omeprazole immediate-release capsules and immediate-release oral suspension are used in adults for the short-term treatment (up to 4 weeks) and symptomatic relief of gastroesophageal reflux disease (GERD).1, 352, 354, 355 Omeprazole magnesium delayed-release and immediate-release formulations are also available in various over-the-counter (OTC) preparations (e.g., capsules, tablets), which are used as self-medication for the short-term treatment and symptomatic relief of frequent heartburn (e.g., 2 or more days a week) in adults.500, 501, 502
In a controlled study in patients with manifestations of GERD (e.g., heartburn) and the absence of erosive esophageal lesions, symptomatic improvement with omeprazole was better than that with placebo.1, 352, 354, 355 Complete resolution of heartburn was reported in 56, 36, or 14% of patients with endoscopically confirmed GERD and in 46, 31, or 13% of all enrolled patients after up to 4 weeks of therapy with omeprazole 20 mg daily, omeprazole 10 mg daily, or placebo, respectively.1, 352, 354, 355
In an uncontrolled, open-label study of 113 pediatric patients 2-16 years of age with a history of symptoms suggestive of nonerosive GERD, patients received an omeprazole dosage of 10 or 20 mg once daily (based on body weight) either as an intact capsule or as an open capsule in applesauce.1, 352 The number and intensity of either pain-related symptoms or vomiting/regurgitation episodes were successfully reduced in 60 or 59% of those receiving omeprazole 10 or 20 mg daily, respectively.1, 352 In another uncontrolled study in 12 children 1-2 years of age with a history of clinically diagnosed GERD, administration of omeprazole (0.5-1.5 mg/kg as an opened capsule in 8.4% sodium bicarbonate solution) for 8 weeks reduced episodes of vomiting/regurgitation from baseline by at least 50% in 9 patients (75%).1, 352
Guidelines have been published by the ACG in 2021 and the American Gastroenterological Association (AGA) in 2022 on the management of GERD.8000, 8001 Both guidelines recommend that classic GERD symptoms (i.e., heartburn, regurgitation, non-cardiac chest pain) without alarm symptoms (e.g., dysphagia, weight loss, GI bleeding) be treated with a trial of a PPI once daily; the AGA recommends a 4- or 8-week PPI trial and the ACG recommends an 8-week PPI trial.8000, 8001 The AGA states that patients with an inadequate response to once-daily PPIs can be increased to a twice-daily dosing frequency or switched to a more effective acid suppressant once daily.8000 Once an adequate response is achieved, PPI therapy should be discontinued.8000, 8001 Patients who experience symptom recurrence or incomplete relief of symptoms should receive a diagnostic esophagogastroduodenoscopy (EGD) to guide further management.8000, 8001
Omeprazole magnesium delayed-release oral suspension is used in adults and children ≥1 month of age, omeprazole delayed-release capsules are used in adults and children ≥2 years of age, and omeprazole immediate-release capsules and immediate-release oral suspension are used in adults for the short-term (4-8 weeks) treatment of endoscopically diagnosed erosive esophagitis in patients with acid-mediated GERD.1, 352, 354, 355
Omeprazole magnesium delayed-release oral suspension is used in adults and children ≥1 year of age, omeprazole delayed-release capsules are used in adults and children ≥2 years of age, and omeprazole immediate-release capsules and immediate-release oral suspension are used in adults as maintenance therapy following healing of erosive esophagitis due to acid-mediated GERD to reduce recurrence of the disease.1, 352, 354, 355
In controlled studies in patients with endoscopically diagnosed erosive esophagitis and symptoms of GERD, reported rates of healing with omeprazole were higher than those with placebo or an H2-receptor antagonist.1, 12, 352, 354, 355 Healing rates from a controlled study were 39, 45, or 7% at 4 weeks and 74, 75, or 14% at 8 weeks for omeprazole 20 mg daily, 40 mg daily, or placebo, respectively.1, 12, 352, 354, 355 In controlled studies in patients with severe GERD and grade 2 erosive esophagitis, omeprazole was found to be significantly more effective than H2-receptor antagonists, leading to faster complete daytime and nighttime heartburn relief.1, 352, 354, 355
In an uncontrolled, open-label, dose-titration study in 57 pediatric patients 1-16 years of age with erosive esophagitis, omeprazole dosages of 0.7-3.5 mg/kg daily were required to promote healing.1, 197, 352 Dosages were initiated at 0.7 mg/kg daily and if therapeutic goals (intraesophageal pH below 4 for less than 6% of a 24-hour period) were not achieved after 5-14 days of treatment, the dosage was increased to 1.4 mg/kg daily.1, 197, 352 Based on additional measurements of intraesophageal pH and/or presence of pathologic acid reflux, the dosages were increased up to a maximum dosage of 3.5 mg/kg or 80 mg daily.197 After titration of omeprazole dosage, patients remained on treatment for 3 months (healing phase); patients with persistent erosive esophagitis after 3 months received a discretionary dosage increase and treatment for an additional 3 months.1, 197, 352 Erosive esophagitis was healed in 90% of children completing the first course of treatment in the healing phase of the study;1, 197, 352 5% received a second treatment course.197 Healing occurred in 44% of the patients receiving omeprazole 0.7 mg/kg daily, and an additional 28% were healed with 1.4 mg/kg daily.197 After 3 months of treatment, 33% of the children had no overall symptoms, 57% had mild reflux symptoms, and 40% had less frequent regurgitation or vomiting.1, 352
Most patients with GERD respond to omeprazole therapy during an initial 8-week course of therapy; however, an additional 4 weeks of therapy may contribute to healing and symptomatic improvement in some patients.1, 352, 354 If symptomatic GERD or erosive esophagitis recurs, the manufacturers state that additional 4- to 8-week courses of omeprazole may be given.1, 352, 354, 355
In a multicenter, double-blind study, endoscopically documented remission of esophagitis was maintained at 6 months in 70, 34, or 11% of patients receiving omeprazole 20 mg daily, omeprazole 20 mg on 3 consecutive days each week, or placebo, respectively.1, 352, 354, 355 In another multicenter, double-blind study in patients with endoscopically confirmed healed esophagitis, endoscopic remission of esophagitis was maintained at 12 months in 77, 58, or 46% of patients receiving omeprazole 20 mg daily, omeprazole 10 mg daily, or ranitidine 150 mg twice daily, respectively.1, 92, 352, 354, 355 However, patients with initial grade 3 or 4 erosive esophagitis required 20 mg of omeprazole daily for maintenance of healing.1, 92, 352, 354, 355
In an uncontrolled, open-label study in 46 pediatric patients who were 1-16 years of age with erosive esophagitis, maintenance dosages were half the dosages that were required for promotion of healing in 54% of the children studied.1, 352 The remaining patients required a dosage increase (0.7 to a maximum of 2.8 mg/kg daily) for all or part of the maintenance period.1, 352 There was no relapse of erosive esophagitis in 41% of the patients, and no symptoms occurred in 63% of the pediatric patients receiving omeprazole maintenance therapy.1, 352
Guidelines published by the ACG in 2021 and the AGA in 2023 on the management of GERD also address the management of erosive esophagitis.8000, 8001 Initial treatment of erosive esophagitis is the same as for GERD (see Clinical Perspective under Gastroesophageal Reflux).8000, 8001 After an initial trial of a PPI for 4-8 weeks, endoscopy should be performed after a period of ≥7 days without PPI therapy.8000, 8001 PPI therapy should be optimized in patients with endoscopic evidence of erosive esophagitis (borderline GERD, Los Angeles grade A esophagitis; GERD, Los Angeles grade B/C/D esophagitis).8000, 8001 Patients with borderline GERD or no erosive disease at baseline should be weaned to the lowest effective PPI dose and/or receive on-demand therapy with H2-receptor antagonists/antacids.8000 Patients with erosive disease at baseline or suspected severe GERD should continue PPI therapy indefinitely and consider anti-reflux intervention for chronic maintenance.8000, 8001
Pathologic Hypersecretory Conditions
Omeprazole delayed-release capsules and omeprazole magnesium delayed-release oral suspension are used in adults for the long-term treatment of pathologic hypersecretory conditions (e.g., Zollinger-Ellison syndrome, multiple endocrine adenomas, systemic mastocytosis).1, 352 The drug reduces gastric acid secretion and associated symptoms (including diarrhea, anorexia, and pain) in patients with these conditions.1, 352 In dosages ranging from 20 mg every other day to 360 mg daily, omeprazole can maintain basal acid secretion below 5 or 10 mEq/hour in patients who have or have not undergone gastric surgery, respectively.1, 352 In addition, omeprazole dosages ranging from 20-360 mg daily have been effective in resolving acid-related pathology in most patients with Zollinger-Ellison syndrome, including those whose symptoms were unresponsive to H2-receptor antagonist therapy.8
Omeprazole immediate-release oral suspension and kit for oral suspension (Konvomep®) are used to decrease the risk of upper GI bleeding in critically ill adults.353, 355
Efficacy of omeprazole was evaluated in a controlled, double-blind, randomized clinical trial in critically ill patients who were randomized to receive either omeprazole immediate-release oral suspension (2 doses of 40 mg 6-8 hours apart on the first day, then 40 mg daily) via a gastric tube or IV cimetidine (300 mg loading dose, then 50-100 mg/hour continuously) for up to 14 days.211, 353, 355 The primary efficacy end point of the study was clinically important upper GI bleeding (defined as bright red blood that did not clear after tube adjustment and 5-10 minutes of lavage or positive test for occult blood in gastric aspirate [“coffee ground material”] for 8 consecutive hours on days 1 and 2, or for 2-4 hours on days 3-14 that did not clear with 100 mL of lavage).211, 353, 355 Omeprazole was at least as effective as IV cimetidine in preventing clinically important upper GI bleeding.211, 353, 355 In the intent-to-treat population, clinically important gastric bleeding occurred in 3.9% of patients receiving omeprazole and in 5.5% of those receiving IV cimetidine.211, 353, 355
Dispensing and Administration Precautions
Omeprazole delayed-release and immediate-release capsules are administered orally;1, 354 oral suspensions of the drug are administered orally or through a gastric tube.352 To avoid decomposition of omeprazole in the acidic pH of the stomach, the commercially available delayed-release capsules and delayed-release oral suspension contain enteric-coated granules of the drug.1, 352 Immediate-release capsules, immediate-release oral suspension, and the kit for oral suspension (Konvomep®) all contain sodium bicarbonate to protect the drug from acid degradation.353, 354, 355
Omeprazole magnesium is also available in fixed-combination capsules containing amoxicillin and rifabutin (Talicia®).359 A co-packaged product containing delayed-release omeprazole capsules, clarithromycin tablets, and amoxicillin capsules (Omeclamox-Pak®) is also commercially available.356 See the full prescribing information for administration of these combination products.356, 359
Antacids may be administered concomitantly with delayed-release preparations of omeprazole.1, 352
For patients receiving continuous feedings via a nasogastric or orogastric tube, enteral feeding should be stopped temporarily for 3 hours before and for 1 hour after administration of preparations of omeprazole oral suspension.353, 355
Store omeprazole delayed-release capsules in tight containers or the original carton at 20-25°C; protect from light and moisture.1, 356 Store packets of omeprazole powder for delayed-release suspension at 25°C (excursions permitted from 15-30°C).352 Store immediate-release capsules in tight, light-resistant containers at 20-25°C and protect from moisture.354 Store packets of omeprazole powder for immediate-release suspension protected from light and moisture at 25°C (excursions permitted from 15-30°C).355 Store omeprazole and sodium bicarbonate powder kit for oral suspension (Konvomep®) at 2-8°C protected from light; do not freeze.353
Omeprazole immediate-release capsules are administered orally at least 1 hour prior to a meal, and must be swallowed intact with water; other liquids should not be used.354 The capsules should not be opened and mixed with food.354 Both the 20- and 40-mg capsules contain the same amount of sodium bicarbonate (1100 mg).354 Therefore, two 20-mg capsules are not equivalent to and should not be substituted for one 40-mg capsule.354
Delayed-release preparations of omeprazole are usually administered once daily, and should be administered before a meal.1
Delayed-release capsules must be swallowed intact and not chewed or crushed.1 However, for adult and pediatric patients with difficulty swallowing, the delayed-release capsule may be opened, the contents carefully emptied on and mixed with a tablespoon of applesauce in a bowl, and the mixture swallowed immediately with a glass of cool water to ensure complete swallowing of the pellets.1 The applesauce should not be hot and should be soft enough to be swallowed without chewing.1 The applesauce and omeprazole enteric-coated pellet mixture should not be stored for future use.1 The manufacturer states that there is similar systemic omeprazole exposure when the 40-mg capsule is administered with or without applesauce, but not the 20-mg capsule.1 When the contents of a 20-mg capsule were administered with applesauce, the peak plasma omeprazole concentration decreased by 25%, but the AUC was not substantially changed.1 However, the clinical importance of this is unknown.1
Store omeprazole delayed-release capsules in tight containers at 20-25°C; protect from light and moisture.1
Powder for Immediate-release Oral Suspension
Omeprazole powder for immediate-release oral suspension should be reconstituted prior to administration by pouring the contents of a single-dose packet containing 20 or 40 mg of the drug into a small cup containing 5-10 mL of water.355 The 20- and 40-mg powder for oral suspension packets contain the same amount of sodium bicarbonate (1680 mg).355 Therefore, two 20-mg packets are not equivalent to and should not be substituted for one 40-mg packet.355 The suspension should be stirred well and ingested immediately.355 The cup should be refilled with water and the contents ingested to ensure complete consumption of the dose.355 The manufacturer states that omeprazole powder for immediate-release oral suspension should not be mixed with any liquids (other than water) or foods.355
The immediate-release oral suspension should be administered on an empty stomach at least 1 hour prior to a meal. 355
If the oral suspension is to be administered through a nasogastric or orogastric tube, the contents of each packet should be reconstituted with approximately 20 mL of water, stirred well, and administered immediately.355 An appropriate-sized syringe should be used to instill the suspension into the tube.355 The suspension should then be flushed through the tube with 20 mL of water.355
Powder for Delayed-release Oral Suspension
Delayed-release preparations of omeprazole are usually administered once daily, and should be administered before a meal.352
Omeprazole magnesium powder for delayed-release oral suspension should be reconstituted prior to administration by pouring the contents of a single-dose packet containing 2.5 or 10 mg of the drug into a small cup containing 5 or 15 mL, respectively, of water.352 The suspension should be stirred well and allowed to thicken for 2-3 minutes.352 Within 30 minutes of preparation, the mixture should be stirred and consumed.352 If any material remains in the cup after the mixture is ingested, additional water should be added, mixed, and ingested immediately.352 If the delayed-release oral suspension is to be administered through a nasogastric or gastric tube, the contents of a 2.5- or 10-mg packet should be mixed with 5 or 15 mL of water, respectively, in a catheter-tipped syringe and then shaken immediately.352 The mixture should be allowed to thicken for 2-3 minutes.352 The mixture should be administered within 30 minutes of reconstitution; prior to administration, the syringe should be shaken again and the mixture injected into the stomach through the nasogastric or gastric tube (French size 6 or larger).352 The syringe should be refilled with additional water (5 or 15 mL, respectively), shaken, and used to flush any remaining drug mixture from the nasogastric or gastric tube into the stomach.352
Powder Kit for Oral Suspension
Omeprazole and sodium bicarbonate powder kit for oral suspension (Konvomep®) contains a bottle of omeprazole powder and a bottle of diluent containing sodium bicarbonate that should be reconstituted before administration.353 Prior to reconstituting, the bottom of the bottle containing the omeprazole powder should be tapped on a hard surface to loosen the powder.353 The diluent bottle should be shaken for several seconds, and then approximately one-third of the diluent transferred to the powder bottle, the cap replaced, and the powder bottle shaken for approximately 30 seconds.353 The second one-third of the diluent should then be transferred into the powder bottle and the bottle shaken vigorously for approximately 30 seconds.353 The remainder of the diluent should then be added to the powder bottle, and the last of the diluent allowed to drain into the powder bottle for 10 seconds.353 The powder bottle should be vigorously shaken for approximately 30 seconds.353 The final concentration of the reconstituted suspension is 2 mg/mL of omeprazole and 84 mg/mL of sodium bicarbonate, and the suspension should be pink to red in color and hazy.353 The reconstituted suspension may be stored at 2-8°C for up to 30 days.353 The reconstituted suspension should be shaken well before each use; an oral dosing device that measures the approximate volume should be used.353 If the oral suspension is to be administered through a nasogastric or orogastric tube, the reconstituted suspension should be shaken well before dispensing 20 mL into a catheter or oral tip syringe.353 The mixture should be injected immediately into the stomach through the nasogastric or orogastric tube (French size 8 or larger).353 The syringe should be refilled with additional water (20 mL), and used to flush any remaining drug mixture from the nasogastric or orogastric tube into the stomach.353
The co-packaged product containing 20-mg delayed-release omeprazole capsules, 500-mg clarithromycin tablets, and 500-mg amoxicillin capsules (Omeclamox-Pak®) requires twice-daily oral administration of 4 pills in the morning and evening before a meal.356 Each dose of 4 pills consists of one 20-mg delayed-release omeprazole capsule, one 500-mg clarithromycin tablet, and two 500-mg amoxicillin capsules (1000 mg of amoxicillin per dose).356 Omeprazole capsules, clarithromycin tablets, and amoxicillin capsules must not be crushed or chewed, and each component swallowed whole.356
Dosage of omeprazole magnesium is expressed in terms of omeprazole.352
Gastroesophageal Reflux Disease (GERD)
For the treatment of symptomatic GERD in pediatric patients 1-16 years of age, a dosage of 5 mg (two 2.5-mg packets) of omeprazole delayed-release oral suspension daily is recommended for patients weighing ≥5 kg to <10 kg; 10 mg (one 10-mg packet) daily is recommended for those weighing ≥10 kg to <20 kg; and 20 mg (two 10-mg packets) daily is recommended for those weighing ≥20 kg.352 Omeprazole can be given once daily for up to 4 weeks for symptomatic GERD.352
For the treatment of symptomatic GERD in pediatric patients 2-16 years of age, a dosage of 10 mg of omeprazole given as the delayed-release capsules once daily is recommended for pediatric patients weighing ≥10 kg to <20 kg, and 20 mg once daily is recommended for those weighing ≥20 kg.1 Omeprazole can be given once daily for up to 4 weeks for symptomatic GERD.1
For the short-term treatment (up to 6 weeks) of erosive esophagitis due to acid-mediated GERD in pediatric patients 1 month to <1 year of age, a dosage of 2.5 mg (one 2.5-mg packet) of omeprazole delayed-release oral suspension once daily is recommended for pediatric patients weighing ≥3 kg to <5 kg; 5 mg (two 2.5-mg packets) once daily is recommended for those weighing ≥5 kg to <10 kg; and 10 mg (one 10-mg packet) once daily is recommended for those weighing ≥10 kg.352 For the short-term treatment (for 4-8 weeks) in pediatric patients 1-16 years of age, a dosage of 5 mg (two 2.5-mg packets) of omeprazole once daily is recommended for pediatric patients weighing ≥5 kg to <10 kg; 10 mg (one 10-mg packet) once daily is recommended for those weighing ≥10 kg to <20 kg; and 20 mg (two 10-mg packets) once daily is recommended for those weighing ≥20 kg.352 Therapy is continued until healing occurs, usually within 4-8 weeks in patients ≥1 year of a an additional 4 weeks of therapy in patients ≥1 year of age (up to 12 weeks for a single course) may contribute to healing and symptomatic improvement in some patients.352 If erosive esophagitis or symptomatic GERD (heartburn) recurs, the manufacturer states that additional 4- to 8-week courses of omeprazole may be considered.352
For the short-term treatment (4-8 weeks) of erosive esophagitis due to acid-mediated GERD in pediatric patients 2-16 years of age, a dosage of 10 mg of omeprazole delayed-release capsules once daily is recommended for those weighing ≥10 kg to <20 kg, and 20 mg once daily is recommended for those weighing ≥20 kg.1 Therapy is continued until healing occurs, usually within 4-8 weeks; an additional 4 weeks of therapy (up to 12 weeks for a single course) may contribute to healing and symptomatic improvement in some patients.1 If erosive esophagitis or symptomatic GERD (heartburn) recurs, the manufacturer states that additional 4- to 8-week courses of omeprazole may be considered.1
For the maintenance of healing of erosive esophagitis to reduce recurrence in pediatric patients 1-16 years of age, a dosage of 5 mg (two 2.5-mg packets) of omeprazole delayed-release oral suspension once daily is recommended for pediatric patients weighing ≥5 kg to <10 kg; 10 mg (one 10-mg packet) once daily is recommended for those weighing ≥10 kg to <20 kg; and 20 mg (two 10-mg packets) once daily is recommended for those weighing ≥20 kg.352 Safety and efficacy of omeprazole maintenance therapy for longer than 1 year have not been established.352
For the maintenance of healing of erosive esophagitis to reduce recurrence in pediatric patients 2-16 years of age, a dosage of 10 mg of omeprazole delayed-release capsules once daily is recommended for those weighing ≥10 kg to <20 kg, and 20 mg once daily is recommended for those weighing ≥20 kg.1 Safety and efficacy of omeprazole maintenance therapy for longer than 1 year have not been established.1
For the short-term treatment of active duodenal ulcer, the usual adult dosage of omeprazole is 20 mg once daily.1, 352, 354, 355 Therapy should be continued until healing occurs, usually within 4 weeks; some patients may benefit from an additional 4 weeks of therapy.1, 352, 354, 355
When omeprazole is used in combination with clarithromycin (dual therapy) for the treatment of Helicobacter pylori ( H. pylori ) infection in patients with active duodenal ulcer, the usual adult dosage of omeprazole is 40 mg once daily (in the morning) for 14 days.1, 352 In patients who have an active ulcer present at the time anti- H. pylori therapy is initiated, an additional 14 days of therapy with omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief.1, 352 When omeprazole is used in combination with clarithromycin and amoxicillin (triple therapy) for the treatment of H. pylori infection in patients with active duodenal ulcer, the usual adult dosage of omeprazole is 20 mg twice daily (morning and evening) for 10 days.1, 352, 355 In patients who have an active ulcer present at the time anti- H. pylori therapy is initiated, an additional 18 days of therapy with omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief.1, 352, 355
For the short-term treatment of erosive esophagitis due to acid-mediated GERD, the usual adult dosage of omeprazole is 20 mg once daily for 4-8 weeks.1, 352, 354, 355 Therapy is continued until healing occurs, usually within 4-8 weeks; an additional 4 weeks of therapy (up to 12 weeks for a single course) may contribute to healing and symptomatic improvement in some patients.1, 352, 354, 355 If erosive esophagitis or symptomatic GERD (heartburn) recurs, the manufacturer states that additional 4- to 8-week courses of omeprazole may be considered.1, 352, 354, 355
For maintenance therapy following healing of erosive esophagitis to reduce recurrence, the usual adult dosage of omeprazole is 20 mg daily.1, 352, 354, 355 Safety and efficacy of omeprazole maintenance therapy for longer than 1 year have not been established.1, 352, 354, 355
For the short-term treatment of active benign gastric ulcer, the usual adult dosage of omeprazole is 40 mg once daily for 4-8 weeks.1, 352, 353, 354, 355
For the short-term, symptomatic treatment of GERD without erosive esophageal lesions, the usual adult dosage of omeprazole is 20 mg once daily for up to 4 weeks.1, 352, 354, 355
For self-medication to relieve symptoms of frequent heartburn in adults, the usual dosage of omeprazole is 20 mg once daily in the morning for 14 days.500, 501, 502 The 14-day course of therapy may be repeated every 4 months, if needed.500, 501, 502
Pathologic Hypersecretory Conditions
For the treatment of pathologic hypersecretory conditions (e.g., Zollinger-Ellison syndrome, multiple endocrine adenomas, systemic mastocytosis), dosages of omeprazole should be individualized according to patient response and tolerance.1, 352 The usual initial adult dosage is 60 mg (as delayed-release capsules or delayed-release oral suspension) once daily.1, 352 Subsequent omeprazole dosage should be adjusted as tolerated and necessary to adequately suppress gastric acid secretion, and therapy continued as long as clinically necessary.1, 352 Daily dosages exceeding 80 mg should be administered in divided doses.1, 352
Oral dosages of up to 360 mg daily (given in 3 divided doses) have been necessary in some patients.1, 352 Omeprazole has been given continuously for more than 5 years in some patients with Zollinger-Ellison syndrome.1, 352
For reduction of risk of upper GI bleeding in critically ill adults, the initial loading dose of omeprazole is 40 mg (as bicarbonate-containing oral suspension) followed by another 40-mg dose after 6-8 hours on the first day; thereafter, 40 mg (as bicarbonate-containing oral suspension) is administered once daily for 14 days.353, 355 Safety and efficacy of omeprazole and sodium bicarbonate oral suspension in critically ill patients for longer than 14 days have not been established.353, 355
When used for maintenance of healing of erosive esophagitis due to GERD, the manufacturers of omeprazole delayed-release capsules and omeprazole delayed-release oral suspension recommend that the omeprazole dosage should be reduced to 10 mg once daily in patients with hepatic impairment (Child-Pugh class A, B, or C).1, 352
The manufacturers recommend avoidance of omeprazole immediate-release capsules and immediate-release oral suspension that contain sodium bicarbonate when used for maintenance of healing of erosive esophagitis in patients with hepatic impairment (Child-Pugh class A, B, or C).354, 355
The manufacturer of co-packaged Omeclamox-Pak® recommends avoiding use in patients with hepatic impairment.356
Although there may be a slight increase in bioavailability in patients with chronic renal impairment (creatinine clearance 10-62 mL/minute per 1.73 m2), dosage adjustment of omeprazole does not appear necessary in patients with such impairment as this increase is not considered clinically meaningful.1, 352, 353, 354, 355
Although the elimination rate of omeprazole is somewhat decreased in geriatric patients and the bioavailability increased, no adjustment of the usual recommended dosage is required in geriatric patients.1, 6, 352, 353, 354, 355, 356
Since the bioavailability of omeprazole appears to be increased substantially in Asian patients, the manufacturers of omeprazole delayed-release capsules and omeprazole delayed-release oral suspension recommend that the omeprazole dosage should be reduced to 10 mg once daily in Asian patients receiving therapy for maintenance of healing of erosive esophagitis.1, 352
The manufacturer recommends avoiding use of omeprazole immediate-release capsules and immediate-release oral suspension that contain sodium bicarbonate for maintenance of healing of erosive esophagitis in Asian patients.354, 355
The manufacturer of copackaged Omeclamox-Pak®recommends avoiding the product in Asian patients unless the benefits outweigh the risks of therapy.356
Pharmacogenomic Considerations
Cytochrome P-450 (CYP) isoenzyme 2C19 (CYP2C19) is a polymorphic enzyme involved in omeprazole metabolism, and systemic exposure to omeprazole varies by a patient's metabolism status.1, 352, 353, 354, 355 Although other alleles are associated with reduced or no enzymatic function, the CYP2C19*1 allele is fully functional, while CYP2C19*2 and CYP2C19*3 alleles are nonfunctional.1, 352, 353, 354, 355 In patients that are extensive metabolizers (e.g., 2 fully functional CYP2C19*1 alleles), omeprazole is primarily metabolized by CYP2C19, while in patients that are poor metabolizers (e.g., 2 loss-of-function CYP2C19*2/*3 alleles), reduced metabolism of omeprazole results in increased systemic exposure to the drug.1, 352, 353, 354, 355 It is estimated that approximately 3% of Caucasian and 15—20% of Asian patients are poor metabolizers of CYP2C19.1, 352, 353, 354, 355
Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines state that, in patients who are CYP2C19 likely intermediate metabolizers (e.g., CYP2C19*1/*9, CYP2C19*9/*17, CYP2C19*9/*9), intermediate metabolizers (e.g., CYP2C19*1/*2, CYP2C19*1/*3, CYP2C19*2/*17, CYP2C19*3/*17), likely poor metabolizers (e.g., CYP2C19*2/*9 or CYP2C19*3/*9), or poor metabolizers (e.g., CYP2C19*2/*2, CYP2C19*3/*3, CYP2C19*2/*3), standard PPI dosages may be initiated; however, for chronic therapy exceeding 12 weeks, a 50% dosage reduction should be considered with monitoring for continued efficacy.357 Alternatively, in patients who are CYP2C19 rapid metabolizers (e.g., CYP2C19*1/*17) or normal metabolizers (e.g., CYP2C19*1/*1), standard PPI dosages may be initiated; however, dosage increases of 50-100% should be considered along with monitoring for efficacy for the treatment of H. pylori infection and erosive esophagitis due to an increased risk of therapeutic failure.357 In patients who are CYP2C19 ultrarapid metabolizers (e.g., CYP2C19*17/*17), an increase in the starting dosage by 100% is recommended (daily dose may be given in divided doses) and patients should be monitored for efficacy due to the risk of therapeutic failure.357
Presence of Gastric Malignancy
Symptomatic response to omeprazole in adults should not be interpreted as precluding the presence of gastric malignancy.1, 352, 353, 354, 355, 356 Additional follow-up and diagnostic testing should be considered in adults, and additionally, an endoscopy in older adults, if suboptimal response or an early symptomatic relapse occurs after completion of proton-pump inhibitor (PPI) treatment.1, 352, 353, 354, 355
Acute Tubulointerstitial Nephritis
Acute tubulointerstitial nephritis (TIN) has been reported in patients receiving PPIs, and can occur at any point during PPI therapy.1, 352, 353, 354, 355, 356 Clinical presentation may vary and can present as symptomatic hypersensitivity reactions to non-specific symptoms of reduced renal function such as malaise, nausea, or anorexia.1, 352, 353, 354, 355, 356 In some reported cases, patients were diagnosed upon biopsy without any extra-renal manifestations (e.g., fever, rash, arthralgia).1, 352, 353, 354, 355, 356 Omeprazole should be discontinued and the patient evaluated if acute TIN is suspected.1, 352, 353, 354, 355, 356
Clostridioides difficile -associated Diarrhea
Observational studies suggest a possible association between use of PPIs and the risk of Clostridioides difficile (formerly known as Clostridium difficile ) infection, including C. difficile -associated diarrhea (CDAD), particularly in hospitalized patients.1, 352, 353, 354, 355 A diagnosis of CDAD should be considered for diarrhea that does not improve.1, 352, 353, 354, 355 Patients should be advised to contact a clinician if watery stools, abdominal pain, and a persistent fever occur.1
Manufacturers recommend that patients receive PPIs at the lowest effective dosage and for the shortest duration appropriate for their clinical condition.1, 352, 353, 354, 355
C. difficile -associated diarrhea has been reported with almost all antibiotic agents.1, 352 For more specific information regarding clarithromycin and amoxicillin indicated for use in combination with omeprazole, refer to the prescribing information for those antibiotics.1, 352
Findings from several observational studies suggest that therapy with PPIs, particularly in high dosages and/or for prolonged periods of time (a year or longer), may be associated with an increased risk of osteoporosis-related fractures of the hip, wrist, or spine.1, 352, 353, 354, 355 Patients should receive PPIs at the lowest effective dosage and for the shortest possible duration appropriate for their clinical condition.1, 352, 353, 354, 355 Patients at risk for osteoporosis-related fractures should be managed according to current treatment guidelines.1, 352, 353, 354, 355
Severe Cutaneous Adverse Reactions
Severe cutaneous adverse reactions (SCARS), including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP), have been reported in association with PPI therapy.1, 352, 353, 354, 355, 356 Omeprazole should be discontinued at the first signs or symptoms of SCARS or other hypersensitivity reactions, and further evaluation should be considered.1, 352, 353, 354, 355, 356
Cutaneous and Systemic Lupus Erythematosus
New onset cases of cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE) and exacerbations of existing autoimmune disease have been reported with PPIs, including omeprazole.1, 352, 353, 354, 355, 356 Most cases of PPI-induced lupus erythematosus were CLE.1, 352, 353, 354, 355, 356 The most common form of CLE reported in patients on PPI therapy is subacute CLE (SCLE), which occurs weeks to years after continuous PPI therapy in patients ranging in age from infants to geriatric patients; generally, histologic findings are observed without organ involvement.1, 352, 353, 354, 355, 356 SLE is less commonly reported than CLE in patients receiving PPIs, and PPI-associated SLE is usually milder than non-drug-induced SLE.1, 352, 353, 354, 355, 356 The onset of SLE usually occurred days to years after initiating PPI therapy primarily in patients ranging from young adults to geriatric patients.1, 352, 353, 354, 355, 356 Most patients with SLE presented with a rash, although arthralgia and cytopenia also occurred.1, 352, 353, 354, 355, 356
Avoid administering PPI therapy for longer than appropriate for the clinical condition.1, 352, 353, 354, 355, 356 If signs or symptoms consistent with CLE or SLE are observed in patients receiving omeprazole therapy, discontinue the drug and refer the patient to an appropriate specialist for evaluation.1, 352, 353, 354, 355, 356 After discontinuation of the PPI alone, the majority of patients improve after 4—12 weeks, although serological testing (e.g., antinuclear antibodies) may remain positive and serological test elevations may take longer to resolve than the clinical manifestations.1, 352, 353, 354, 355, 356
Because omeprazole inhibits cytochrome P-450 (CYP) isoenzyme CYP2C19, concurrent use of omeprazole with clopidogrel, which is metabolized to its active metabolite by CYP2C19, reduces the pharmacologic activity of clopidogrel.1, 352, 353, 354, 355 Concomitant use of omeprazole with clopidogrel should be avoided.1, 352, 353, 354, 355 Even when administration is separated by 12 hours, concomitant use of clopidogrel with 80 mg of omeprazole results in reduced pharmacologic activity of clopidogrel.1, 352, 353, 354, 355 In patients receiving omeprazole who require antiplatelet therapy, consider an alternative antiplatelet agent.1, 352, 353, 354, 355
Cyanocobalamin (Vitamin B12) Deficiency
Cyanocobalamin deficiency has been reported rarely in patients receiving acid-suppressive therapy.1, 352, 353, 354, 355 Chronic daily administration of acid-suppressive therapy over long periods (e.g., longer than 3 years) can cause malabsorption of cyanocobalamin due to hypo- or achlorhydria.1, 352, 353, 354, 355 Consider a diagnosis of cyanocobalamin deficiency in patients receiving omeprazole therapy if clinical symptoms consistent with the diagnosis are observed.1, 352, 353, 354, 355
Hypomagnesemia and Mineral Metabolism
Long-term use (for at least 3 months or, in most cases, for longer than one year) of PPIs may rarely be associated with an increased risk of hypomagnesemia (symptomatic and asymptomatic).1, 352, 353, 354, 355 Serious adverse events include tetany, arrhythmias, and seizures.1, 352, 353, 354 The presence of hypomagnesemia can exacerbate underlying hypocalcemia in at-risk patients or lead to hypocalcemia and/or hypokalemia.1, 352, 353, 354, 355 In most patients receiving PPI therapy who developed hypomagnesemia, treatment required discontinuation of the PPI and magnesium replacement.1, 352, 353, 354, 355 In patients expected to receive long-term therapy with a PPI or in those receiving a PPI concomitantly with digoxin or drugs that may cause hypomagnesemia (e.g., diuretics), clinicians may consider measurement of serum magnesium concentrations prior to initiation of prescription PPI therapy and periodically thereafter.1, 352, 353, 354, 355
Consider monitoring magnesium and calcium levels prior to starting omeprazole and periodic monitoring thereafter in patients at risk for hypocalcemia (e.g., hypoparathyroidism).1, 352, 353, 354, 355 Supplement magnesium and calcium as needed during omeprazole therapy.1, 352, 353, 354, 355 Consider discontinuing the PPI if hypocalcemia is refractory to treatment.1, 352, 353, 354, 355
Interaction with St. John's Wort or Rifampin
Omeprazole is extensively metabolized by the CYP enzyme system and concentrations of omeprazole can be substantially reduced by drugs that induce CYP2C19 or CYP3A4 (e.g., rifampin, St. John's wort [ Hypericum perforatum ]).1, 352, 353, 354, 355 Concomitant use of omeprazole with St. John's wort or rifampin should be avoided.1, 352, 353, 354, 355
Interaction with Diagnostic Investigations for Neuroendocrine Tumors
Increases in intragastric pH may result in hypergastrinemia, enterochromaffin-like cell hyperplasia, and increased serum chromogranin A (CgA) concentrations.1, 352, 353, 354, 355 Increased CgA concentrations may produce false-positive results for diagnostic tests for neuroendocrine tumors.1, 352, 353, 354, 355 Clinicians should temporarily discontinue omeprazole therapy ≥14 days before assessing CgA concentrations and consider repeating the test if initial CgA concentrations are high.1, 352, 353, 354, 355 Use of the same commercial laboratory is recommended for testing as reference ranges between tests may vary.1, 352, 353, 354, 355
Data suggest that concomitant use of PPIs, including omeprazole, with methotrexate (primarily at high doses) may result in elevated and prolonged serum methotrexate and/or metabolite concentrations and possibly result in methotrexate toxicity.1, 352, 353, 354, 355
Manufacturers of omeprazole state that temporary discontinuance of PPI therapy may be considered in some patients receiving high-dose methotrexate therapy.1, 352, 353, 354, 355
PPI therapy is associated with an increased risk of fundic gland polyps, and the risk increases with long-term use (especially longer than 1 year).1, 352, 353, 354, 355 Most patients who developed fundic gland polyps were asymptomatic and fundic gland polyps were discovered incidentally on endoscopy.1 Patients should receive PPIs for the shortest duration appropriate for their clinical condition.1, 352, 353, 354, 355
Considerations with Sodium Content
Each mL of reconstituted omeprazole and sodium bicarbonate powder kit for oral suspension (Konvomep®) contains 84 mg of sodium bicarbonate (equivalent to 1 mEq/mL of sodium); total content of sodium from inactive and active ingredients of reconstituted Konvomep® is 1.14 mEq/mL.353 Each 20 mL dose of Konvomep® delivers 40 mg of omeprazole and 1680 mg of sodium bicarbonate (526 mg [22.8 mEq] of sodium).353 Each 20- or 40-mg packet of omeprazole powder for immediate-release oral suspension contains 1680 mg of sodium bicarbonate (460 mg [20 mEq] of sodium).355 Each 20- or 40-mg immediate-release capsule of omeprazole contains 1100 mg of sodium bicarbonate (304 mg [13 mEq] of sodium).354 The sodium content of these preparations should be taken into consideration in patients whose sodium intake must be restricted or in those at risk for congestive heart failure; increased sodium intake may produce edema and weight increase.353, 354, 355 Sodium bicarbonate may cause metabolic alkalosis, and chronic use with calcium or milk may cause milk-alkali syndrome.353, 354, 355 Avoid omeprazole and sodium bicarbonate in patients with Bartter's syndrome, hypokalemia, hypocalcemia, or acid-base abnormalities.353, 354, 355
Reproductive studies in rats and rabbits using omeprazole dosages during organogenesis of up to 138 and 69.1 mg/kg daily (about 34 times the human dosage of 40 mg daily based on body surface area [BSA]), respectively, have not revealed evidence of teratogenicity.1, 352, 353, 354, 355 However, in rabbits given omeprazole dosages of 6.9-69.1 mg/kg daily during organogenesis (about 3.4-34 times the human dosage of 40 mg daily based on BSA), dose-related increases in embryolethality, fetal resorptions, and pregnancy loss occurred.1, 352, 353, 354, 355 In rats, dose-related embryo/fetal toxicity and postnatal developmental toxicity were observed in offspring resulting from administration of omeprazole in dosages of 13.8-138 mg/kg daily (about 3.4-34 times the human dosage of 40 mg daily based on BSA) prior to mating through the lactation period.1, 352, 353, 354, 355
Reproductive studies of oral esomeprazole (an enantiomer of omeprazole) in rats and rabbits during organogenesis using dosages approximately 68 and 42 times the usual human dosage of 40 mg daily based on BSA, did not reveal evidence of embryo/fetal toxicity.1, 352, 353, 354, 355 When administered through most of pregnancy and lactation, effects on bone morphology were observed in rat offspring at dosages approximately 34 times the human dosage of 40 mg daily based on BSA of esomeprazole; however, when confined to administration during the gestational period only, no effects on bone morphology were observed in another study.1, 352, 353, 354, 355
There are no adequate and well controlled studies using omeprazole in pregnant women.1, 352, 353, 354, 355 Available epidemiologic data have not demonstrated an increased risk of major congenital malformations or other adverse pregnancy outcomes with first trimester exposure to omeprazole.1, 352, 353, 354, 355 Reproductive studies in rats and rabbits using omeprazole dosages approximately 3.4-34 times the human dosage of 40 mg daily (based on BSA) resulted in dose-dependent increases in embryolethality.1, 352, 353, 354, 355
A population-based retrospective cohort epidemiologic study using data from the Swedish Medical Birth Registry reported on outcomes in infants whose mothers used omeprazole during pregnancy; most (about 86%) were exposed to omeprazole during the first trimester, 5% during and beyond the first trimester, and about 14% were exposed only after the first trimester of pregnancy.1, 352, 353, 354, 355 The number of infants exposed to omeprazole in utero with any malformation, low birth weight, low Apgar score, or hospitalization was similar to the number in this population.1, 352, 353, 354, 355 The number of infants born with ventricular septal defects and the number of stillborn infants was slightly higher in the omeprazole-exposed infants than the expected number in this population.1, 352, 353, 354, 355
In a population-based retrospective cohort study in Denmark reporting on 1800 live births whose mothers received omeprazole during the first trimester and 837,317 live births whose mothers did not receive a PPI, the overall rate of birth defects was 2.9% in infants whose mothers received omeprazole during the first trimester and 2.6% in infants born to mothers not exposed to any PPI during the first trimester.1, 352, 353, 354, 355
In a retrospective cohort study, the incidence of congenital malformations in 689 women who received omeprazole or histamine H2-antagonists in the first trimester of pregnancy was compared with a control group of women who were not exposed to acid-suppressant drugs.1, 352, 353, 354, 355 The malformation rate associated with histamine H2-antagonists exposure was 5.5%, the malformation rate for nonexposed women was 4.1%, and the malformation rate associated with omeprazole exposure was 3.6%.1, 352, 353, 354, 355
A small prospective cohort study followed women exposed to omeprazole (89% during the first trimester) during pregnancy; major congenital malformations occurred in 4% of live births in omeprazole-exposed women, 2.8% of disease-paired controls, and 2% exposed to non-teratogenic agents.1, 352, 353, 354, 355 Rates of spontaneous and elective abortions, preterm deliveries, gestational age at delivery, and mean birth weight were similar among the groups.1, 352, 353, 354, 355
The manufacturers state that several studies reported that adverse short-term effects were not observed in infants when a single oral or IV dose of omeprazole was administered to pregnant women as premedication for cesarean section under general anesthesia.1, 352, 353, 354, 355
Available data on sodium bicarbonate administration during pregnancy have not identified a drug-associated risk of major fetal malformations or miscarriage.353
Limited data suggest omeprazole is distributed into human milk.1, 352 The effects of omeprazole on milk production and on the breast-fed infant are unknown.1, 352 Consider the developmental and health benefits of breast-feeding along with the mother's clinical need for the drug and any potential adverse effects on the breast-fed infant from omeprazole or from the underlying maternal condition.1, 352
Safety and efficacy of omeprazole magnesium delayed-release oral suspension have been established for the treatment of erosive esophagitis due to acid-mediated gastroesophageal reflux disease (GERD) in pediatric patients ≥1 month of age.352 Safety and efficacy of omeprazole magnesium delayed-release oral suspension have also been established for the treatment of symptomatic GERD and maintenance of healing of erosive esophagitis in pediatric patients 1-16 years of age.352 Safety and efficacy of omeprazole delayed-release capsules have been established for the treatment of symptomatic GERD and maintenance of healing of erosive esophagitis in pediatric patients 2-16 years of age.1 Use in pediatric patients is supported by adequate and well-controlled studies in adults and uncontrolled safety, efficacy, and pharmacokinetic studies in pediatric and adolescent patients.1, 352
Safety and efficacy of omeprazole magnesium delayed-release oral suspension are not established in pediatric patients <1 month of age or for other uses in pediatric patients.352 Safety and efficacy of omeprazole delayed-release capsules in pediatric patients <1 year of age for the treatment of symptomatic GERD or maintenance of healing of erosive esophagitis have not been established.1 Safety and efficacy of omeprazole delayed-release capsules have not been established in pediatric patients for the treatment of active duodenal ulcer, H. pylori eradication to reduce the risk of duodenal ulcer recurrence, treatment of active benign gastric ulcer, or pathological hypersecretory conditions.1 Safety and efficacy of omeprazole immediate-release capsules and oral suspension have not been established in pediatric patients.354, 355
Safety and efficacy of omeprazole and sodium bicarbonate powder kit for oral suspension (Konvomep®) have not been established in pediatric patients.353
Safety and efficacy of co-packaged omeprazole delayed-release capsules, clarithromycin tablets, and amoxicillin capsules (Omeclamox-Pak®) have not been established in pediatric patients with H. pylori .356
Respiratory adverse reactions and accidental injuries have been reported more frequently in pediatric patients of all ages than in adults.1, 352 Otitis and fever have been reported more frequently in patients less than one year of age and patients from one month to less one year to less than 2 years of age, respectively, than in other pediatric and adult patients.352
In US and European clinical trials, more than 2000 patients treated with omeprazole were ≥65 years of age.1, 352, 353, 354, 355, 356 Although no overall differences in efficacy or safety were observed between geriatric and younger patients, and other clinical experience revealed no evidence of age-related differences, the possibility that some older patients may exhibit increased sensitivity to the drug cannot be ruled out.1, 352, 353, 354, 355, 356
In patients with chronic liver disease (Child-Pugh Class A, B, and C), the bioavailability of omeprazole increased by 100% compared to healthy subjects, which reflects a decreased first-pass effect and an increase in the elimination half-life from 0.5—1 hours to 3 hours.1, 352, 353, 354, 355, 356
In patients with chronic renal impairment (creatinine clearance 10—62 mL/minute per 1.73 m2), the disposition of omeprazole is similar to that in normal renal function, although there may be a slight increase in bioavailability; this increase is not considered clinically meaningful.1, 352, 353, 354, 355
Pharmacogenomic Considerations
Most PPIs undergo metabolism by CYP2C19 into inactive metabolites.357 The highly polymorphic CYP2C19 genotype has been associated with variability in exposure to first-generation PPIs, which include omeprazole, lansoprazole, and pantoprazole.357 Systemic exposure to omeprazole varies by a patient's metabolism status (poor metabolizers > intermediate metabolizers > extensive metabolizers).1 Consult the Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for dosing recommendations based on metabolism status.357
Adverse effects reported in ≥2% of adults receiving omeprazole in clinical trials include headache, abdominal pain, nausea, diarrhea, vomiting, and flatulence.1, 352, 353, 354, 355
Adverse effects reported in pediatric patients 2—16 years of age receiving omeprazole were similar to those reported in adults, except for more frequently reported respiratory system events and fever.1, 352
In vivo, omeprazole is a substrate and inhibitor of cytochrome P-450 (CYP) isoenzyme 2C19, and a substrate of CYP3A4.1, 352, 353, 354, 355 Omeprazole is also an inhibitor of CYP2C19 in vitro.1, 352, 353, 354, 355
When co-packaged delayed-release omeprazole capsules, clarithromycin tablets, and amoxicillin capsules (Omeclamox-Pak®) are prescribed, drug interactions should be considered for each individual component.356 Refer to the Omeclamox-Pak® prescribing information for drug interaction information.356
Drugs Metabolized by Hepatic Microsomal Enzymes
There have been reports of omeprazole interacting with other drugs metabolized by the CYP450 enzyme system (e.g., cyclosporine, disulfiram).1, 352, 353, 354, 355, 356 Concomitant use of omeprazole with CYP2C19 substrates may affect exposure of the CYP2C19 substrate.1, 352, 353, 354, 355, 356 Concomitant use of omeprazole with strong CYP2C19 or CYP3A4 inducers decreases exposure of omeprazole.1, 352, 353, 354, 355, 356 Concomitant use of omeprazole with CYP2C19 or CYP3A4 inhibitors increases exposure of omeprazole.1, 352, 353, 354, 355, 356 Clinicians should monitor patients to determine if a dosage adjustment or if alternate therapy should be considered when such medications are used concomitantly with omeprazole.1, 352, 353, 354, 355, 356
Drugs that Cause Hypomagnesemia
In patients receiving diuretics (i.e., loop or thiazide diuretics) or other drugs that may cause hypomagnesemia, monitoring of magnesium concentrations should be considered prior to initiation of prescription proton-pump inhibitor (PPI) therapy and periodically thereafter.1, 352, 353, 354, 355
The possibility that omeprazole-induced increases in gastric pH may affect the bioavailability of drugs such as itraconazole, ketoconazole, mycophenolate mofetil, nilotinib, dasatinib, iron salts, or erlotinib (where gastric acidity is an important determinant in oral absorption) should be considered.1, 352, 353, 354, 355 Refer to the prescribing information for other drugs that depend on gastric pH for absorption.1, 352, 353, 354, 355
The effects of PPIs on antiretroviral agents are variable; the clinical importance and mechanisms behind these interactions are not always known.1, 352, 353, 354, 355 See the prescribing information for antiretroviral products (including those containing ritonavir) when used concomitantly with omeprazole.1, 352, 353, 354, 355
Concomitant use of omeprazole 40 mg once daily (given 2 hours before an atazanavir dose) and atazanavir 400 mg daily decreased the AUC and peak plasma concentrations of atazanavir by 94 and 96%, respectively, and may decrease the therapeutic effect of the antiretroviral agent and promote the development of drug resistance.1, 352, 353, 354, 355, 356 The manufacturers of omeprazole state that concomitant use of omeprazole with atazanavir should be avoided; other antiretroviral agents are available that do not have clinically important interactions with omeprazole.1, 352, 353, 354, 355, 356
Concomitant use of omeprazole 40 mg once daily (given 30 minutes before a nelfinavir dose) and nelfinavir 1.25 g twice daily decreased peak plasma concentrations and AUC of nelfinavir by 37 and 36%, respectively, and of its major active metabolite M8 by 89 and 92%, respectively.1, 352, 353, 354, 355, 356 Decreased exposure to nelfinavir may result in a loss of therapeutic effect and promote the development of antiretroviral drug resistance.1, 352, 353, 354, 355, 356 The manufacturers of omeprazole state that concomitant use with nelfinavir should be avoided; other antiretroviral agents are available that do not have clinically important interactions with omeprazole.1, 352, 353, 354, 355, 356
Concomitant use of omeprazole 20 mg daily with rilpivirine 150 mg daily resulted in decreased plasma concentrations and AUC of rilpivirine by 40%.1, 352, 353, 354, 355 Decreased exposure to rilpivirine may result in a loss of therapeutic effect and promote the development of antiretroviral drug resistance.1, 352, 353, 354, 355 Concomitant use of rilpivirine with PPIs, including omeprazole, is contraindicated.1, 352, 353, 354, 355
Concomitant use of omeprazole (40 mg daily for one week) and cilostazol in healthy individuals resulted in increased peak plasma concentrations and AUC of cilostazol (by 18 and 26%, respectively) and of one of its active metabolites, 3,4-dihydro-cilostazol, by 29 and 69%, respectively; this active metabolite has 4-7 times the activity of cilostazol.1, 352, 353, 354, 355, 356 Therefore, reduction of cilostazol dosage (from 100 mg twice daily to 50 mg twice daily) is recommended during concomitant use.1, 352, 353, 354, 355, 356
Concomitant use of omeprazole with the CYP2C19 substrate citalopram may lead to increased citalopram exposure, resulting in an increased risk of QT prolongation.1, 352, 353, 354, 355 When omeprazole is used concomitantly with citalopram, limit the dosage of citalopram to 20 mg daily.1, 352, 353, 354, 355
Concomitant administration of clarithromycin (500 mg 3 times daily) and omeprazole (40 mg daily) in healthy men resulted in increases of 30, 89, and 34% in the peak plasma concentration, AUC, and elimination half-life, respectively, of omeprazole.1, 352, 353, 354, 355 The peak plasma concentrations of clarithromycin and 14-hydroxyclarithromycin were also increased by 10 and 45%, and AUC by 15 and 45%, respectively, when administered with omeprazole.1, 352, 353, 354, 355
See the clarithromycin prescribing information for contraindications, warnings and precautions of the drug.1, 352, 353, 354, 355
Because omeprazole inhibits CYP2C19, concurrent use of omeprazole with clopidogrel, which is metabolized to its active metabolite by CYP2C19, reduces plasma concentrations of clopidogrel's active metabolite and potentially may reduce clopidogrel's clinical efficacy.1, 352, 353, 354, 355
In a crossover clinical trial in healthy individuals who received clopidogrel (a 300-mg loading dose, followed by 75 mg daily) alone or with omeprazole (80 mg administered at the same time as the clopidogrel dose) for 5 days, exposure to the active metabolite of clopidogrel was decreased by 46 and 42% on days 1 and 5, respectively, when the drugs were administered simultaneously.1, 352, 353, 354, 355 When administration of the 2 drugs (at the same dosages) was separated by 12 hours in another study, results were similar.1, 352, 353, 354, 355 Results from another crossover study in healthy individuals showed a similar pharmacokinetic interaction between clopidogrel (300-mg loading dose, then 75 mg daily) and omeprazole (80 mg daily) administered for 30 days.1, 352, 353, 354, 355 Exposure to the active metabolite of clopidogrel was reduced by 41-46% over this time period.1, 352, 353, 354, 355
Concomitant use of clopidogrel and omeprazole should be avoided.1, 352, 353, 354, 355 Consider an alternative antiplatelet agent.1, 352, 353, 354, 355
Concomitant use of omeprazole with the CYP2C19 substrate diazepam results in increased diazepam exposure.1, 352, 353, 354, 355 In a pharmacokinetic study, concomitant administration of omeprazole 20 mg once daily with diazepam 0.1 mg/kg given IV reduced diazepam clearance by 27%, and increased diazepam half-life by 36%.1, 352, 353, 354, 355 When omeprazole is used concomitantly with diazepam, monitor patients for increased sedation and reduce the dosage of diazepam as needed.1, 352, 353, 354, 355
Concomitant use of omeprazole with digoxin may result in increased digoxin exposure.1, 352, 353, 354, 355 Concomitant use of omeprazole 20 mg once daily and digoxin in healthy individuals increased digoxin bioavailability by 10% (up to 30% in some individuals).1, 352, 353, 354, 355, 356 When omeprazole is used concomitantly with digoxin, monitor serum digoxin concentrations and adjust the digoxin dosage as needed to maintain therapeutic concentrations.1, 352, 353, 354, 355, 356
The manufacturers recommend that in patients receiving digoxin with a PPI, monitoring of magnesium concentrations should be considered prior to initiation of prescription PPI therapy and periodically thereafter.1, 352, 353, 354, 355
Concomitant use of omeprazole with methotrexate at primarily high doses can result in elevated and prolonged serum concentrations of methotrexate and/or its metabolite hydroxymethotrexate, which may lead to methotrexate toxicity.1, 352, 353, 354, 355 No formal studies of interactions between high-dose methotrexate and PPIs have been conducted to date.1, 352, 353, 354, 355
The manufacturer of omeprazole states that temporary discontinuance of PPI therapy may be considered in some patients receiving high-dose methotrexate therapy.1, 352, 353, 354, 355
Omeprazole can reduce the absorption of mycophenolate mofetil (MMF) due to its effect on reducing intragastric acidity.1, 352, 353, 354, 355, 356 Concomitant use of omeprazole in healthy patients and in transplant patients receiving MMF has been reported to reduce the exposure to mycophenolic acid (MPA; active metabolite), although the clinical importance of reduced MPA exposure on transplant rejection has not been established.1, 352, 353, 354, 355, 356 Concomitant use of omeprazole 20 mg twice daily for 4 days with a single 1000-mg dose of MMF one hour following omeprazole resulted in a 52% reduction in MPA peak plasma concentrations and a 23% reduction in AUC.1, 352, 353, 354, 355, 356 Omeprazole should be used with caution in transplant recipients receiving MMF therapy.1, 352, 353, 354, 355, 356
Concomitant use of omeprazole with phenytoin, a CYP2C19 substrate, may result in increased exposure to phenytoin.1, 352, 353, 354, 355 If omeprazole is used concomitantly with phenytoin, monitoring of phenytoin serum concentrations is recommended.1, 352, 353, 354, 355 Dosage adjustment of phenytoin may be required in order to maintain therapeutic phenytoin concentrations.1, 352, 353, 354, 355
Concomitant use of drugs such as rifampin that induce CYP2C19 or CYP3A4 can substantially decrease omeprazole concentrations.1, 352, 353, 354, 355 Concomitant use of omeprazole with rifampin should be avoided.1, 352, 353, 354, 355
St. John's Wort ( Hypericum perforatum )
Concomitant use of drugs such as St. John's wort ( Hypericum perforatum ) that induce CYP2C19 or CYP3A4 can substantially decrease omeprazole concentrations.1, 352, 353, 354, 355 Concomitant use of omeprazole with St. John's wort should be avoided.1, 352, 353, 354, 355
Concomitant use of omeprazole with tacrolimus may result in increased serum concentrations of tacrolimus, especially in transplant patients who are intermediate or poor metabolizers of CYP2C19.1, 352, 353, 354, 355 If omeprazole is used concomitantly with tacrolimus, monitoring of tacrolimus serum concentrations is recommended.1, 352, 353, 354, 355 Dosage adjustment of tacrolimus may be required in order to maintain therapeutic tacrolimus concentrations.1, 352, 353, 354, 355
Concomitant use of omeprazole (40 mg daily for 7 days) with voriconazole (a combined inhibitor of CYP2C19 and CYP3A4; 400 mg every 12 hours for one day, then 200 mg for 6 days) in healthy individuals increased the peak plasma concentrations and AUC of omeprazole by an average of twofold and fourfold, respectively.1, 352, 353, 354, 355, 356 Dosage adjustment of omeprazole is not usually required but may be considered in patients receiving high dosages, such as those with Zollinger-Ellison syndrome.1, 352
Increases in international normalized ratio (INR) and prothrombin time have been reported in patients receiving warfarin concomitantly with a PPI, including omeprazole.1, 352, 353, 354, 355 Because such increases may lead to abnormal bleeding and death, monitoring of INR and prothrombin time and adjustment of warfarin dosage may be necessary in patients receiving warfarin and a PPI concomitantly.1, 352, 353, 354, 355
Diagnostic Tests for Neuroendocrine Tumors
Serum chromogranin A (CgA) concentrations increase secondary to decreased gastric acidity with PPI therapy.1, 352, 353, 354, 355 Increased CgA concentrations may produce false-positive results for diagnostic tests for neuroendocrine tumors.1, 352, 353, 354, 355 Clinicians should temporarily discontinue omeprazole therapy at least 14 days before assessing CgA concentrations and consider repeating the test if initial CgA concentrations are high.1, 352, 353, 354, 355 Use of the same commercial laboratory is recommended for serial testing (e.g., for monitoring) as reference ranges between tests may vary.1, 352, 353, 354, 355
Patients receiving omeprazole therapy may have overresponsive gastric secretion in response to secretin stimulation testing, which can falsely suggest gastrinoma.1, 352, 353, 354, 355 Clinicians should temporarily discontinue omeprazole therapy at least 14 days before conducting secretin stimulation testing in order to allow gastrin levels to return to baseline.1, 352, 353, 354, 355
Urine Tests for Tetrahydrocannabinol
In patients receiving PPI therapy, false positive urine screening tests for tetrahydrocannabinol (THC) have been reported.1, 352, 353, 354, 355 Confirm positive test results using an alternative testing method.1, 352, 353, 354, 355
Omeprazole is a substituted benzimidazole gastric antisecretory agent.1, 352, 353, 354, 355 Omeprazole binds to hydrogen/potassium adenosine triphosphatase (H+/K+-exchanging ATPase) in gastric parietal cells; inactivation of this enzyme system (also known as the proton, hydrogen, or acid pump) blocks the final step in the secretion of hydrochloric acid by these cells.1, 352, 353, 354, 355 Omeprazole inhibits basal and stimulated gastric acid secretion; in addition, because the drug inhibits the final step in the secretory pathway, it inhibits such secretion regardless of the stimulus.1, 352, 353, 354, 355 The degree of inhibition of gastric acid secretion is related to the dosage and duration of therapy of omeprazole.1, 352, 353, 354, 355
Following oral administration of omeprazole, peak plasma concentrations and AUC are dose proportional up to doses of 40 mg.1 Peak plasma concentrations and AUC exert a greater than linear response for doses >40 mg because of a saturable first-pass effect.1 Because the omeprazole molecule is acid labile, the drug is administered orally as a delayed-release capsule or oral suspension or as a buffered immediate-release capsule or oral suspension.1, 352, 354, 355 The suspension is also commercially available as a kit containing omeprazole and sodium bicarbonate.353 The commercially available omeprazole delayed-release capsules increase oral bioavailability of the drug by delaying absorption until after the capsule leaves the stomach; peak plasma concentrations of omeprazole occur 30 minutes to 3.5 hours after administration.1 The absolute bioavailability of omeprazole delayed-release capsules is 30-40% at doses of 20—40 mg, which is largely due to presystemic metabolism; with repeated administration, bioavailability of the capsules increases slightly.1 Following repeated administration of omeprazole magnesium delayed-release oral suspension, peak plasma concentrations are attained within 1.5—2 hours.352 Mean peak plasma concentrations of omeprazole and sodium bicarbonate preparations occur at about 30 minutes after oral administration.353, 354, 355 Relative to administration 1 hour before a meal, omeprazole exposure is reduced when omeprazole and sodium bicarbonate preparations are administered 1 hour following a meal.353, 354, 355 Following comparable weight-based doses, children 2<5 years of age have lower AUCs than children 6<16 years of age or adults, which are comparable.1
Omeprazole is approximately 95% protein bound.1, 352, 353, 354 Omeprazole undergoes extensive metabolism via the cytochrome P-450 (CYP) enzyme system, primarily via CYP2C19, and to a lesser extent via CYP3A4.1, 352, 353, 354 Following oral administration of a single dose of omeprazole, approximately 77% of the dose is excreted in urine as various metabolites; the remainder of the dose is excreted in feces.1, 352, 353, 354, 355 In healthy individuals, the half-life of delayed-release omeprazole preparations is 30 minutes to 1 hour.1, 352 The half-life of omeprazole and sodium bicarbonate preparations is approximately 1 hour.353, 354, 355
Following oral administration of omeprazole, inhibition of gastric acid secretion is apparent within 1 hour, peaks within 2 hours, and persists for up to 72 hours.1, 352 Inhibition of gastric acid secretion increases with continuous drug administration and reaches a plateau after about 4 days of omeprazole therapy.1, 352 Following discontinuance of omeprazole therapy, gastric acid secretion returns to baseline over a 3-5 day period.1, 352
Additional Information
The American Society of Health-System Pharmacists, Inc. represents that the information provided in the accompanying monograph was formulated with a reasonable standard of care, and in conformity with professional standards in the field. Readers are advised that decisions regarding use of drugs are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and that the information contained in the monograph is provided for informational purposes only. The manufacturer's labeling should be consulted for more detailed information. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information contained in the monograph is not a substitute for medical care.
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|---|---|---|---|
Oral | Capsules, delayed-release (containing enteric-coated granules) | 10 mg* | Omeprazole capsules, delayed-release | |
20 mg* | Omeprazole capsules, delayed-release | |||
40 mg* | Omeprazole capsules, delayed-release |
* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|---|---|---|---|
Oral | For suspension, delayed-release (containing enteric-coated granules) | 2.5 mg (of omeprazole) per packet | PriLOSEC® | AstraZeneca |
10 mg (of omeprazole) per packet | PriLOSEC® | AstraZeneca |
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|---|---|---|---|
Oral | For suspension, powder kit | Bottle of 0.18 grams omeprazole powder and bottle of diluent containing sodium bicarbonate 7.56 grams per 90 mL | Konvomep® (2 mg omeprazole and 84 mg sodium bicarbonate per mL [after reconstitution]) | Azurity Pharmaceuticals |
Bottle of 0.3 grams omeprazole powder and bottle of diluent containing sodium bicarbonate 12.6 grams per 150 mL | Konvomep® (2 mg omeprazole and 84 mg sodium bicarbonate per mL [after reconstitution]) | Azurity Pharmaceuticals | ||
Bottle of 0.6 grams omeprazole powder and bottle of diluent containing sodium bicarbonate 25.2 grams per 300 mL | Konvomep® (2 mg omeprazole and 84 mg sodium bicarbonate per mL [after reconstitution]) | |||
Capsules, immediate-release | 20 mg omeprazole and 1100 mg sodium bicarbonate* | Omeprazole capsules, immediate-release | ||
40 mg omeprazole and 1100 mg sodium bicarbonate* | Omeprazole capsules, immediate-release | |||
For suspension, immediate-release powder | 20 mg of omeprazole and 1680 mg of sodium bicarbonate per packet* | Omeprazole suspension, immediate-release powder | ||
40 mg of omeprazole and 1680 mg of sodium bicarbonate per packet* | Omeprazole suspension, immediate-release powder |
* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|---|---|---|---|
Oral | Various | 20 mg omeprazole, 500 mg clarithromycin, 500 mg amoxicillin | Omeclamox-Pak® (Pack of 10 daily administration cards for morning and evening; each containing two omeprazole delayed-release capsules, two clarithromycin tablets, and four amoxicillin capsules) | |
10 mg omeprazole, amoxicillin 250 mg, rifabutin 12.5 mg | Talicia® |
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