omeprazole

BEERS REMS

Symptomatic GERD.
Erosive esophagitis due to acid-mediated GERD.
Maintenance of healing of erosive esophagitis due to acid-mediated GERD.
Duodenal ulcers (with or without anti-infectives for Helicobacter pylori).
Short-term treatment of active benign gastric ulcer.
Pathologic hypersecretory conditions, including Zollinger-Ellison syndrome.
Reduction of risk of GI bleeding in critically ill patients.

OTC

Heartburn occurring at least twice per week.

Action ⬆ ⬇

Binds to an enzyme on gastric parietal cells in the presence of acidic gastric pH, preventing the final transport of hydrogen ions into the gastric lumen.

Therapeutic effects:

Diminished accumulation of acid in the gastric lumen with lessened gastroesophageal reflux.
Healing of duodenal ulcers.

Pharmacokinetics ⬆ ⬇

Absorption: Rapidly absorbed following oral administration; immediate release formulation contains bicarbonate to prevent acid degradation.

Distribution: Good distribution into gastric parietal cells.

Protein Binding: 95%.

Metabolism/Excretion: Mostly metabolized by the liver via the CYP2C19 isoenzyme and to a lesser extent by the CYP3A4 isoenzyme; the CYP2C19 isoenzyme exhibits genetic polymorphism (15–20% of Asian patients and 3–5% of White and Black patients may be poor metabolizers and may have significantly ↑ omeprazole concentrations and an ↑ risk of adverse effects); inactive metabolites are excreted in urine (77%) and feces.

Half-Life: 0.5–1 hr (↑ in hepatic impairment).

Time/Action Profile ⬆ ⬇

(antisecretory effects)

ROUTE	ONSET	PEAK	DURATION
PO	within 1 hr	within 2 hr	72–96 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity to omeprazole or related drugs (benzimidazoles);
Concurrent use of rilpivirine.

Use Cautiously in:

Hepatic impairment (dose ↓ may be necessary);
Patients using high doses for >1 yr (↑ risk of hip, wrist, or spine fractures; fundic gland polyps);
Patients using therapy for >3 yr (↑ risk of vitamin B₁₂ deficiency);
Pre-existing risk of hypocalcemia;
Lactation: Safety not established in breastfeeding;
Pedi: Children <1 mo (safety and effectiveness not established);
Geri: Appears on Beers list. ↑ risk of Clostridioides difficile infection, pneumonia, GI malignancies, bone loss, and fractures in older adults. Avoid scheduled use for >8 wk in older adults unless for high-risk patients (e.g., oral corticosteroid or chronic NSAID use) or patients with erosive esophagitis, Barrett esophagitis, pathological hypersecretory condition, or demonstrated need for maintenance therapy (e.g., failure of H₂ antagonist).

Adv. Reactions/Side Effects ⬆ ⬇

CV: chest pain

Derm: ACUTE GENERALIZED EXANTHEMATOUS PUSTULOSIS, cutaneous lupus erythematosus, DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS), itching, rash, STEVENS-JOHNSON SYNDROME, TOXIC EPIDERMAL NECROLYSIS

F and E: hypocalcemia (especially if treatment duration ≥3 mo), hypokalemia(especially if treatment duration ≥3 mo), hypomagnesemia(especially if treatment duration ≥3 mo)

GI: abdominal pain, CLOSTRIDIOIDES DIFFICILE-ASSOCIATED DIARRHEA (CDAD), constipation, diarrhea, flatulence, fundic gland polyps, nausea, vomiting

GU: acute tubulointerstitial nephritis

MS: bone fracture

Neuro: dizziness, drowsiness, fatigue, headache, weakness

Misc: HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS, ANGIOEDEMA, OR TUBULOINTERSTITIAL NEPHRITIS), systemic lupus erythematosus, vitamin B₁₂ deficiency

Interactions ⬆ ⬇

Drug-drug:

May significantly ↓ levels and effectiveness of rilpivirine; concurrent use contraindicated.
May ↑ levels and risk of toxicity of antifungal agents, cilostazol, citalopram, diazepam, triazolam, cyclosporine, phenytoin, tacrolimus, and warfarin; consider ↓ dose of cilostazol from 100 mg twice daily to 50 mg twice daily.
May ↓ absorption and effectiveness of drugs requiring acidic pH, including ketoconazole, itraconazole, iron salts, dasatinib, erlotinib, nilotinib, atazanavir, nelfinavir, and mycophenolate mofetil; avoid concurrent use with atazanavir and nelfinavir.
May ↑ levels and risk of toxicity of digoxin and methotrexate.
Voriconazole may ↑ levels and risk of toxicity.
May ↓ the antiplatelet effects of clopidogrel; avoid concurrent use.
Rifampin may ↓ levels and effectiveness; avoid concurrent use.
Hypomagnesemia and hypokalemia ↑ risk of digoxin toxicity.

Drug-Natural Products:

St. John's wort may ↓ levels and effectiveness; avoid concurrent use.

Route/Dosage ⬆ ⬇

Symptomatic GERD

PO (Adults ): 20 mg once daily for up to 4 wk
PO (Children 1–16 yr and ≥20 kg): 20 mg once daily for up to 4 wk.
PO (Children 1–16 yr and 10–<20 kg): 10 mg once daily for up to 4 wk.
PO (Children 1–16 yr and 5–<10 kg): 5 mg once daily for up to 4 wk.

Erosive Esophagitis Due to Acid-Mediated GERD

PO (Adults ): 20 mg once daily for 4–8 wk
PO (Children 1–16 yr and ≥20 kg): 20 mg once daily for 4–8 wk.
PO (Children 1–16 yr and 10–<20 kg): 10 mg once daily for 4–8 wk.
PO (Children 1–16 yr and 5–<10 kg): 5 mg once daily for 4–8 wk.
PO (Children 1 mo–<1 yr and ≥10 kg): 10 mg once daily for up to 6 wk.
PO (Children 1 mo–<1 yr and 5–<10 kg): 5 mg once daily for up to 6 wk.
PO (Children 1 mo–<1 yr and 3–<5 kg): 2.5 mg once daily for up to 6 wk.

Maintenance of Healing of Erosive Esophagitis Due to Acid-Mediated GERD

PO (Adults ): 20 mg once daily for up to 12 mo.
PO (Children 1–16 yr and ≥20 kg): 20 mg once daily for up to 12 mo.
PO (Children 1–16 yr and 10–<20 kg): 10 mg once daily for up to 12 mo.
PO (Children 1–16 yr and 5–<10 kg): 5 mg once daily for up to 12 mo.

Duodenal Ulcers Associated With Helicobacter pylori

PO (Adults ): 40 mg once daily in the morning with clarithromycin for 2 wk, then 20 mg once daily for 2 wk or 20 mg twice daily with clarithromycin 500 mg twice daily and amoxicillin 1000 mg twice daily for 10 days (if ulcer is present at beginning of therapy, continue omeprazole 20 mg daily for 18 more days); has also been used with clarithromycin and metronidazole.

Gastric Ulcer

PO (Adults ): 40 mg once daily for 4–6 wk.

Gastric Hypersecretory Conditions

PO (Adults ): 60 mg once daily initially; may ↑ up to 120 mg 3 times daily (doses >80 mg/day should be given in divided doses);

Reduction of Risk of GI Bleeding in Critically Ill Patients.

PO (Adults ): 40 mg initially, then another 40 mg 6–8 hr later, followed by 40 mg once daily for up to 14 days.

Heartburn (OTC Use)

PO (Adults ): 20 mg once daily for up to 14 days.

Availability ⬆ ⬇

(Generic available)

Delayed-release tablets: 10 mg; 20 mg^OTC
Delayed-release capsules: 10 mg; 20 mg; 40 mg
Delayed-release powder for oral suspension peach-mint flavor: 2.5 mg/packet; 10 mg/packet
In combination with: metronidazole and clarithromycin in a compliance package (Losec 1-2-3 M); amoxicillin and clarithromycin in a compliance package (Losec 1-2-3-A) (both in Canada only); amoxicillin and rifabutin (Talicia); sodium bicarbonate (Konvomep, Zegerid [OTC]). See Appendix [not included in this PDA edition].

Assessment ⬆ ⬇

Assess patient routinely for epigastric or abdominal pain and frank or occult blood in the stool, emesis, or gastric aspirate.
Monitor bowel function. Report diarrhea, abdominal cramping, fever, and bloody stools to health care provider promptly as a sign of CDAD. May begin up to several weeks following cessation of therapy.
Monitor for signs and symptoms of vitamin B₁₂ deficiency with prolonged use (>1 yr) (pallor, fatigue, weakness, numbness or tingling in the hands and feet, difficulty with balance or coordination, confusion, glossitis [beefy tongue]). Consider screening for deficiency every 1–2 yr.

Lab Test Considerations:

Monitor CBC with differential periodically during therapy.
- May ↑ AST, ALT, alkaline phosphatase, and bilirubin.
- May ↑ serum gastrin concentrations during first 1–2 wk of therapy. Levels return to normal after discontinuation of omeprazole.
- Monitor INR and prothrombin time in patients taking warfarin.
- May cause hypomagnesemia. Monitor serum magnesium prior to and periodically during therapy.
- May cause false-positive results in diagnostic investigations for neuroendocrine tumors due to ↑ serum chromogranin A (CgA) levels secondary to drug-induced ↓ gastric acidity. Temporarily stop omeprazole ≥14 days before assessing CgA levels and consider repeating test if initial CgA levels are high.

Implementation ⬆ ⬇

Do not confuse Prilosec with Prozac or Pristiq. Do not confuse omeprazole with fomepizole.
PO: Administer doses 30 min before meals, preferably in the morning. DNC: Swallow capsules and tablets whole; do not crush or chew. Capsules may be opened and sprinkled on cool applesauce; entire mixture should be ingested immediately and followed by a drink of water. Do not store for future use.
- Powder for oral suspension: Administer on empty stomach, ≥1 hr before a meal. Empty contents of 2.5-mg packet into 5 mL of water or contents of 10-mg packet into 15 mL of water. Stir. Leave 2–3 min to thicken. Stir and drink within 30 min. If material remains after drinking, add more water, stir, and drink immediately. For patients with nasogastric or enteral feeding, suspend feeding for 3 hr before and 1 hr after administration. Empty packet contents into a small cup containing 5 mL of water for 2.5-mg dose or 15 mL water for 10-mg dose using a catheter-tipped syringe. Do not use other liquids or foods. Immediately shake syringe and leave 2–3 min to thicken. Administer within 30 min. Refill the syringe with an equal amount of water. Shake and flush remaining contents from nasogastric or gastric tube into stomach.
- May be administered concurrently with antacids.

Patient/Family Teaching ⬆ ⬇

Explain the purpose and side effects of omeprazole. Instruct patient to take medication as directed before meals for the full course of therapy, even if feeling better. Take missed doses as soon as remembered but not if almost time for next dose. Do not double doses. Advise patient to read Patient Information before starting and with each Rx refill in case of changes.
May cause occasional drowsiness or dizziness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
Instruct patient using multiple daily doses for longer than a year to report symptoms of osteoporosis-related fractures (hip, wrist, spine).
Instruct patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care provider before taking any new medications, especially St. John's wort, clopidogrel, or rifampin.
Advise patient to avoid alcohol, products containing aspirin or NSAIDs, and foods that may cause an increase in GI irritation.
Advise patient to report onset of black, tarry stools; diarrhea; abdominal pain; or persistent headache to health care provider promptly.
Instruct patient to notify health care provider of onset of black, tarry stools; diarrhea; abdominal pain; or persistent headache or if fever and diarrhea develop, especially if stool contains blood, pus, or mucus. Advise patient not to treat diarrhea without consulting health care provider.
Rep: Advise women of reproductive potential to notify health care provider if pregnancy is planned or suspected or if breastfeeding.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇