Drug class: Erythromycins
CAS number: 114-07-8

Medically reviewed by Drugs.com on Dec 22, 2023. Written by ASHP.

Introduction

Erythromycin is a macrolide antibiotic.

Erythromycin Dosage and Administration

Administration

Erythromycin base is administered orally. The manufacturers of erythromycin delayed-release tablets state that these tablets are well absorbed and may be given without regard to meals.¹²⁴ The manufacturers of erythromycin delayed-release capsules (containing enteric-coated pellets)¹²³ and erythromycin film-coated tablets¹²⁵ state that optimal absorption generally occurs when these preparations are administered in the fasting state (at least 30 minutes and, preferably, 2 hours before or after meals). Delayed-release tablets containing enteric-coated particles are well absorbed in most patients and may be given without regard to meals, but the manufacturer states that optimal absorption still occurs if such tablets are administered in the fasting state (at least 30 minutes and, preferably, 2 hours before meals).¹⁰⁴

The commercially available delayed-release capsules containing enteric-coated pellets of erythromycin (ERYC) may be swallowed intact or the entire contents of a capsule(s) may be sprinkled on a small amount of applesauce immediately prior to administration; subdividing the contents of a capsule is not recommended. The enteric-coated pellets contained in the capsules should not be chewed or crushed. If the capsule contents are administered by sprinkling on applesauce, the patient should drink some water after swallowing the applesauce to ensure that the pellets are swallowed. If the pellets are accidentally spilled, the dose preparation should be started over with a new capsule.

Dosage

The usual adult oral dosage of erythromycin is 250 mg every 6 hours,^{123 124 125} 333 mg every 8 hours,^{104 124 125} or 500 mg every 12 hours.^{104 123 124 125} In severe infections, dosage may be increased up to 4 g daily; however, a twice-daily dosing schedule is not recommended when dosages exceeding 1 g daily are administered.^{104 123 124}

The usual oral erythromycin dosage in children is 30–50 mg/kg daily given in 2–4 equally divided doses.^{104 107 123 124 125} For more severe infections, this dosage may be doubled but should not exceed 4 g daily.^{104 123 124 125} A twice-daily dosing schedule is not recommended when dosages exceeding 1 g daily are administered.^{104 123 124}

Pharyngitis and Tonsillitis

If erythromycin 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.^{102 104 107 124 125}

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.^{102 104 107 123 124 125}

When selecting anti-infectives for prophylaxis of recurrent rheumatic fever, the current recommendations published by the American Heart Association (AHA) should be consulted.¹⁰²

Syphilis

Although penicillin G is the drug of choice for all stages of syphilis,^{100 101 107} the manufacturers state that 30–40 g of oral erythromycin has been given in divided doses over 10–15 days for the treatment of primary syphilis.^{104 123 124 125} 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.^{101 107}

Lyme Disease

For the treatment of early localized or early disseminated Lyme disease^{† [off-label]} associated with erythema migrans (but without neurologic involvement or third-degree AV heart block) in adults who are allergic to or intolerant of penicillins and cephalosporins and in whom tetracyclines are contraindicated, the Infectious Diseases Society of America (IDSA) suggests an oral erythromycin dosage of 500 mg 4 times daily for 14–21 days.¹⁰³ For the treatment of early localized or early disseminated Lyme disease^{† [off-label]} associated with erythema migrans (but without neurologic involvement or third-degree AV heart block) in children who are allergic to or intolerant of penicillins or cephalosporins and cannot receive a tetracycline (e.g., younger than 8 years of age), the IDSA suggests an oral erythromycin dosage of 12.5 mg/kg (maximum dose: 500 mg) 4 times daily for 14–21 days.¹⁰³ Some clinicians suggest that if erythromycin is used in the treatment of early Lyme disease, adults should receive 250 mg 4 times daily for 14–21 days and children should receive 30 mg/kg daily in 3 divided doses (or 250 mg 3 times daily) for 14–21 days.¹¹¹ However, erythromycin may not be as effective as other recommended agents (e.g., oral doxycycline, oral amoxicillin) for the treatment of Lyme disease,^{107 108 109 110} and patients treated with macrolides should be monitored closely.¹⁰³

Gonorrhea and Associated Infections

When an oral erythromycin is indicated for the treatment of coexisting chlamydial infections in conjunction with therapy of uncomplicated or disseminated gonococcal infections, the CDC recommends that adults and adolescents receive 500 mg of erythromycin orally 4 times daily for 7 days.¹⁰¹ Erythromycins generally are indicated for these infections in pregnant women and in other adults when tetracyclines are contraindicated or not tolerated.¹⁰¹

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 including meningitis or endocarditis receive presumptive treatment for possible coexisting chlamydial infections.¹⁰⁷ 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.¹⁰⁷

Although erythromycin is not included in the current CDC recommendations for the treatment of acute pelvic inflammatory disease (PID) caused by N. gonorrhoeae,¹⁰¹ some manufacturers recommend a regimen of 500 mg of erythromycin (as the lactobionate) IV every 6 hours for 3 days followed by an oral regimen of 333 mg of erythromycin (as the base or stearate) every 8 hours for 7 days or 500 mg every 12 hours for 7 days for the treatment of these infections.^{104 124 125} However, some clinicians believe this oral dosage is inadequate and recommend 500 mg every 6 hours for 7–10 days.

Nongonococcal Urethritis

When oral erythromycin is used as an alternative to azithromycin or doxycycline for the treatment of nongonococcal urethritis in adults and adolescents, the CDC and others recommend a regimen of 500 mg of erythromycin 4 times daily for 7 days.^{100 101} Alternatively, a regimen of 666 mg of erythromycin may be given every 8 hours for at least 7 days.^{104 124}

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

Chlamydial Infections

For the treatment of uncomplicated urethral, endocervical, or rectal infections caused by Chlamydia trachomatis in nonpregnant adults and adolescents when azithromycin or doxycycline cannot be used, the CDC and others recommend oral erythromycin in a dosage of 500 mg 4 times daily for 7 days.^{100 101 104 107 123 124 125} Alternatively, a dosage of 666 mg every 8 hours for 7 days can be used.^{104 124} The dosage of oral erythromycin recommended by the 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 or 666 mg every 8 hours for at least 7 days.^{100 101 104 123 124 125} Women who cannot tolerate this regimen may receive a dosage of 500 mg every 12 hours, 333 mg every 8 hours, or 250 mg 4 times daily for at least 14 days.^{104 124}

For the treatment of pneumonia caused by C. trachomatis in infants, the recommended dosage of oral erythromycin is 50 mg/kg daily given in 4 divided doses for 14 days;^{100 101 107} follow-up is recommended and a second course of therapy may be necessary.^{101 107}

For the treatment of ophthalmia neonatorum caused by C. trachomatis, the recommended dosage of oral erythromycin is 50 mg/kg daily given in 4 divided doses for 14 days;^{100 101 107} follow-up is recommended and a second course of therapy may be necessary.^{101 107}

If erythromycin is used as an alternative to doxycycline for the treatment of genital, inguinal, or anorectal infections caused by a lymphogranuloma venereum serotype of C. trachomatis ^{† [off-label]}, the CDC and others recommend that adults and adolescents receive an oral dosage of 500 mg 4 times daily for 21 days.^{100 101 107}

Chancroid

For the treatment of chancroid^{† [off-label]} (genital ulcers caused by Haemophilus ducreyi), the CDC and others recommend that adults receive an oral erythromycin dosage of 500 mg 3–4 times daily for 7 days.^{100 101}

The CDC recommends that patients with chancroid be examined 3–7 days after initiation of anti-infective therapy.¹⁰¹ If the regimen was effective, symptomatic improvement in the ulcers is evident within 3 days and objective improvement is evident within 7 days.¹⁰¹ The time required for complete healing is related to the size of the ulcer; large ulcers may require more than 2 weeks to heal.¹⁰¹ Healing of ulcers may be slower in uncircumcised men who have ulcers under the foreskin.¹⁰¹ Resolution of fluctuant lymphadenopathy is slower than that of ulcers, and needle aspiration or incision and drainage may be necessary even during otherwise effective anti-infective therapy.¹⁰¹ While needle aspiration of buboes is a simpler procedure, incision and drainage of buboes may be preferred.¹⁰¹ If clinical improvement is not evident within 3–7 days, consideration should be given to the possibility that the diagnosis was incorrect, there is coinfection with another sexually transmitted disease, the patient was noncompliant with the regimen, the strain of H. ducreyi is resistant to the anti-infective agent used, or the patient is HIV seropositive.¹⁰¹

Granuloma Inguinale (Donovanosis)

When oral erythromycin is used as an alternative to co-trimoxazole or doxycycline for the treatment of granuloma inguinale^{† [off-label]} (Donovanosis) caused by Calymmatobacterium granulomatis (e.g., in pregnant or lactating women), the CDC recommends a dosage of 500 mg orally 4 times daily for at least 3 weeks.¹⁰¹ If lesions do not respond within the first few days of therapy, some experts recommend that a parenteral aminoglycoside (e.g., 1 mg/kg of gentamicin IV every 8 hours) be added to the regimen.¹⁰¹ Addition of an aminoglycoside should be strongly considered when treating donovanosis in pregnant or lactating women or in patients with human immunodeficiency virus (HIV) infection.¹⁰¹ Despite effective anti-infective therapy, donovanosis may relapse 6–18 months later.¹⁰¹

Intestinal Amebiasis

Although erythromycin is not considered a drug of choice for the treatment of intestinal amebiasis caused by Entamoeba histolytica,¹⁰⁷ the manufacturers state that adults may receive 250 mg of erythromycin every 6 hours,^{104 123 125} 333 mg every 8 hours,¹⁰⁴ or 500 mg every 12 hours^{104 125} for 10–14 days and that children may be given 30–50 mg/kg daily in divided doses for 10–14 days.^{104 123 124 125}

Diphtheria

Treatment

When used as an adjunct to diphtheria antitoxin for the treatment of diphtheria, the usual dosage of erythromycin is 40–50 mg/kg daily (maximum 2 g daily) for 14 days.^{107 126} Patients usually are no longer contagious 48 hours after initiation of anti-infective therapy.¹²⁶ Eradication of the organism should be confirmed by 2 consecutive negative cultures following completion of therapy.^{107 126}

Prophylaxis

For prevention of diphtheria in household or intimate contacts of patients with respiratory or cutaneous diphtheria, the CDC and US Public Health Service Advisory Committee on Immunization Practices (ACIP) recommend that children receive erythromycin in a dosage of 40 mg/kg daily and that adults receive 1 g daily for 7–10 days.^{106 126} The American Academy of Pediatrics (AAP) recommends that these contacts receive an erythromycin dosage of 40–50 mg/kg daily (maximum 2 g daily) for 7 days.¹⁰⁷

Household or intimate contacts of patients with diphtheria should receive anti-infective prophylaxis regardless of their immunization status and should be closely monitored for symptoms of diphtheria for 7 days.^{106 107 126} In addition, contacts who are inadequately immunized against diphtheria (i.e., have previously received fewer than 3 doses of diphtheria toxoid) or whose immunization status is unknown should receive an immediate dose of an age-appropriate diphtheria toxoid preparation and the primary series should be completed according to the recommended schedule.^{107 126} Contacts who are fully immunized should receive an immediate booster dose of an age-appropriate diphtheria toxoid preparation if it has been 5 years or longer since their last booster dose.^{107 126}

Diphtheria Carrier State

When erythromycin is used to eliminate the diphtheria carrier state in identified carriers of toxigenic Corynebacterium diphtheriae, the ACIP and AAP recommend that adults and children receive 7–10 days of the drug in the dosages specified above for prevention of diphtheria.^{106 107} Follow-up cultures should be obtained at least 2 weeks after completion of therapy; if cultures are positive, an additional 10-day course of oral erythromycin should be given and additional follow-up cultures obtained.^{106 107}

Pertussis

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.^{106 107} While a shorter duration of erythromycin therapy (e.g., 7 or 10 days) may be effective in some patients, ^{107 112} prophylaxis failures and bacteriologic relapse of pertussis have been reported with erythromycin regimens shorter than 14 days.^{112 113 114 115 116 117 118} Therefore, the CDC,¹²⁶ ACIP,¹⁰⁶ AAP,¹⁰⁷ and some clinicians^{113 114 115 116 117 118} 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.¹²⁶ 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.¹²⁶

Legionnaires’ Disease

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 combination with rifampin.^{104 107 119 122 123 124 125} 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.^{107 119 122} The duration of therapy in patients with Legionnaires’s disease usually is 10–21 days;^{107 119 122} some clinicians recommend 14 days of therapy for patients with mild disease and 21 days for those who are immunocompromised or have severe disease.¹⁰⁷

Preoperative Intestinal Antisepsis

For preoperative intestinal antisepsis in patients undergoing colorectal surgery, oral erythromycin is usually given in conjunction with oral neomycin sulfate as an adjunct to mechanical cleansing of the large intestine. It is generally recommended that if surgery is scheduled for 8 a.m., 1 g of erythromycin and 1 g of neomycin sulfate should be administered at 1 p.m., 2 p.m., and 11 p.m. on the day preceding surgery.^{105 124}

Chemistry and Stability

Chemistry

Erythromycin occurs as a white or slightly yellow, odorless or practically odorless, bitter, crystalline powder. The drug has a solubility of approximately 1 mg/mL in water and is soluble in alcohol at 25°C.

Stability

Erythromycin delayed-release capsules (containing enteric-coated pellets),¹²³ delayed-release tablets (containing enteric-coated particles),¹⁰⁴ delayed-release (enteric coated) tablets,¹²⁴ and film-coated tablets¹²⁵ should be stored at a temperature not exceeding 30°C.¹⁰⁴ The delayed-release capsules should be protected from moisture and excessive heat.¹²³

Additional Information

For further information on chemistry, mechanism of action, spectrum, resistance, pharmacokinetics, uses, cautions, drug interactions, laboratory test interferences, and dosage and administration of erythromycin, see the Erythromycins General Statement 8:12.12.04.

Preparations

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.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

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