Erythromycin stearate is administered orally. Optimal absorption occurs when the drug is administered in the fasting state or immediately before a meal.111
Dosage of erythromycin stearate is expressed in terms of erythromycin.
The usual adult dosage of erythromycin as the stearate is 250 mg every 6 hours or 500 mg every 12 hours.111 In severe infections, dosage in adults may be increased to 4 g or more daily.111 A twice-daily dosing schedule is not recommended when dosages greater than 1 g daily are administered;111 some clinicians believe the twice-daily schedule is inadequate for all but minor infections caused by highly susceptible organisms.
The usual erythromycin dosage in children is 30-50 mg/kg daily given in 2-4 equally divided doses.102,111 For more severe infections, this dosage may be doubled but should not exceed 4 g daily.111 An alternative pediatric dosage of 0.9-3 g/m2 daily given in 4 equally divided doses has been recommended. A twice-daily dosing schedule is not recommended when dosages greater than 1 g daily are administered;111 some clinicians believe the twice-daily schedule is inadequate for all but minor infections caused by highly susceptible organisms.
If erythromycin stearate is used for the treatment of pharyngitis and tonsillitis caused by Streptococcus pyogenes (group A β-hemolytic streptococci), the drug should be given in the usual dosage for 10 days or longer.104,111
Prophylaxis of Recurrent Rheumatic Fever
For continuous prophylaxis to prevent recurrences in patients with a history of rheumatic heart disease, the usual oral dosage of erythromycin is 250 mg twice daily.102,104,111
When selecting anti-infectives for prophylaxis of recurrent rheumatic fever, the current recommendations published by the American Heart Association (AHA) should be consulted.104
Prevention of Bacterial Endocarditis
Because of adverse GI effects and the complicated pharmacokinetics of the various erythromycin formulations, current recommendations of the AHA for prevention of bacterial endocarditis no longer include erythromycins as alternatives to penicillins in penicillin-allergic patients.112 However, the AHA states that practitioners who have successfully used an erythromycin for prophylaxis in individual patients may choose to continue using these agents.112 If erythromycin stearate is used for prophylaxis of bacterial endocarditis in penicillin-allergic patients at risk who are undergoing certain dental or upper respiratory procedures, the AHA recommends that adults receive 1 g of erythromycin as the stearate 2 hours before the procedure and 500 mg 6 hours later and that children receive 20 mg/kg 2 hours before the procedure and 10 mg/kg 6 hours later.113 Pediatric dosage should not exceed adult dosage.113
When selecting anti-infectives for prophylaxis of bacterial endocarditis, the current recommendations published by the AHA should be consulted.112
Although penicillin G is the drug of choice for all stages of syphilis,101,102 the manufacturer states that 30-40 g of oral erythromycin has been given in divided doses over 10-15 days for the treatment of primary syphilis.111 Erythromycin is no longer included in US Centers for Disease Control and Prevention (CDC) recommendations for the treatment of any form of syphilis in adults or adolescents (including primary, secondary, latent, or tertiary syphilis or neurosyphilis) and is not recommended for the treatment of congenital syphilis or syphilis in older infants and children.101 In addition, erythromycin is no longer recommended by the CDC or American Academy of Pediatrics (AAP) for the treatment of syphilis in pregnant women who are hypersensitive to penicillin since numerous treatment failures (including in the fetus) have been reported with the drug.101,102
Gonorrhea and Associated Infections
The AAP currently recommends that all children beyond the neonatal period being treated for uncomplicated vulvovaginal, urethral, or pharyngeal gonorrhea, epididymitis, proctitis, or disseminated gonococcal infections receive presumptive treatment for possible coexisting chlamydial infections.102 If oral erythromycin is used for presumptive treatment of chlamydial infection in children who weigh less than 45 kg, the AAP recommends a dosage of 50 mg/kg daily (maximum 2 g daily) given in 4 divided doses for 7 days.102
Although erythromycin is not included in the current CDC recommendations for the treatment of acute pelvic inflammatory disease (PID) caused by N. gonorrhoeae ,101 the manufacturer recommends a regimen of 500 mg of erythromycin (as the lactobionate) IV every 6 hours for 3 days followed by 500 mg of oral erythromycin every 12 hours or 333 mg every 8 hours for 7 days for the treatment of these infections.111 However, some clinicians believe this oral dosage is inadequate and recommend 500 mg every 6 hours for 7-10 days.
When erythromycin is used as an alternative to azithromycin or doxycycline for the treatment of nongonococcal urethritis† in adults and adolescents, the CDC recommends an oral erythromycin dosage of 500 mg 4 times daily for 7 days.101
Patients with recurrent and persistent urethritis who were not compliant with the full course of erythromycin therapy or who were reexposed to untreated sexual partner(s) should receive a second course of oral erythromycin.101 If the patient has recurrent and persistent urethritis, was compliant with the regimen, and reexposure can be excluded, the CDC recommends a regimen of 500 mg of oral erythromycin 4 times daily for 7 days given in conjunction with a single 2-g dose of oral metronidazole.101
For the treatment of uncomplicated urethral, endocervical, or rectal infections caused by Chlamydia trachomatis in nonpregnant adults and adolescents, the CDC recommends oral erythromycin in a dosage of 500 mg 4 times daily for 7 days.101 The dosage of oral erythromycin recommended by CDC for the treatment of these infections in children weighing 45 kg or less is 50 mg/kg daily given in 4 divided doses for 14 days.101
For the treatment of chlamydial urogenital infections during pregnancy, the recommended dosage of oral erythromycin is 500 mg 4 times daily for 7 days; for women who cannot tolerate this regimen, a dosage of 250 mg 4 times daily for 14 days may be used.101,102,111
Although erythromycin is not considered a drug of choice for the treatment of intestinal amebiasis caused by Entamoeba histolytica ,102 the manufacturers state that adults may receive 250 mg of erythromycin as the stearate 4 times daily for 10-14 days, and children may receive 30-50 mg/kg daily in divided doses for 10-14 days.111
Although the optimum dosage and duration of erythromycin for the treatment of pertussis or prevention in susceptible contacts have not been established, a dosage of 1 g daily in adults and 40-50 mg/kg daily (maximum 2 g daily) in children given in divided doses for 14 days usually is recommended.105,106,107,108,109,110,114,117 While a shorter duration of erythromycin therapy (e.g., 7 or 10 days) may be effective in some patients, 102,115 prophylaxis failures and bacteriologic relapse of pertussis have been reported with erythromycin regimens shorter than 14 days.105,106,107,108,109,110,114 Therefore, the CDC,103 US Public Health Service Advisory Committee on Immunization Practices (ACIP),117 AAP,102 and some clinicians105,106,108,109,110 recommend that a 14-day course of erythromycin therapy be used for treatment or prevention of pertussis.
Although data from controlled studies are lacking, the CDC recommends that all household and other close contacts of individuals with pertussis receive a 14-day regimen of prophylaxis (regardless of age and vaccination status) since this may prevent or minimize transmission of the disease.103 In addition, all close contacts younger than 7 years of age who are not fully immunized against pertussis should receive the remaining required doses of a preparation containing pertussis vaccine (using minimal intervals between doses) and those who are fully immunized but have not received a vaccine dose within the last 3 years should receive a booster dose of a pertussis vaccine preparation.103
Although the optimum dosage and duration of erythromycin for the treatment of Legionnaires' disease have not been established, dosages of 1-4 g daily in divided doses have been given alone or in conjunction with rifampin.102,115,116 A parenteral regimen usually is necessary for the initial treatment of severe Legionnaires' disease and the addition of rifampin is recommended during the first 3-5 days of therapy in severely ill and/or immunocompromised patients; after a response is obtained, rifampin can be discontinued and therapy changed to oral erythromycin.102,115,116 The duration of therapy in patients with Legionnaires' disease usually is 10-21 days;102,115,116 some clinicians recommend 14 days of therapy for patients with mild disease and 21 days for those who are immunocompromised or have severe disease. 102