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Active ingredient: Erythromycin - Brands, Medical Use, Clinical Data

Brands, Medical Use, Clinical Data

Drug Category

  • Anti-bacterial Agents

Dosage Forms

  • Capsule
  • Capsule (enteric-coated)
  • Liquid
  • Ointment
  • Powder
  • Powder for solution
  • Solution
  • Suspension
  • Tablet
  • Tablet (enteric-coated)

Brands / Synonyms

Abboticin; Abomacetin; Ak-mycin; Akne-Mycin; Aknin; Benzamycin; Benzamycin Pak; Bristamycin; Dotycin; Dumotrycin; E-Base; E-Glades; E-Mycin; E-mycin E; E-Solve 2; E.E.S.; EM; Emgel; EMU; Eritrocina; Ermycin; Ery-Sol; ERY-TAB; Eryc; Eryc 125; Eryc Sprinkles; Erycen; Erycette; Erycin; Erycinum; Eryderm; Erygel; Erymax; Erypar; Eryped; Erythra-Derm; Erythro; Erythro-Statin; Erythrocin; Erythrocin Stearate; Erythrogran; Erythroguent; Erythromast 36; Erythromid; Erythromycin; Erythromycin A; Erythromycin and Benzoyl Peroxide Gel; Erythromycin B; Erythromycin Base; Erythromycin Delayed-Release; Erythromycin Estolate; Erythromycin Ethylsuccinate; Erythromycin Lactobionate; Erythromycin oxime; Erythromycin sodium lauryl sulfate; Erythromycin Stearate; Ethril 250; ETS; Ilocaps; Ilosone; Ilotycin; Ilotycin Gluceptate; IndermRetcin; Kesso-Mycin; Mephamycin; Pantomicina; PCE; Pediamycin; Pediazole; Pfizer-e; Propiocine; R-P Mycin; Robimycin; Sans-Acne; Sansac; Serp-AFD; Staticin; Stiemycin; T-Stat; Taimoxin-F; Theramycin Z; Torlamicina; Wemid; Wyamycin E; Wyamycin S


For use in the treatment of infections caused by susceptible strains of microorganisms in the following diseases: respiratory tract infections (upper and lower) of mild to moderate degree, pertussis (whooping cough), as adjunct to antitoxin in infections due to Corynebacterium diphtheriae, in the treatment of infections due to Corynebacterium minutissimum, intestinal amebiasis caused by Entamoeba histolytica, acute pelvic inflammatory disease caused by Neisseria gonorrhoeae, skin and soft tissue infections of mild to moderate severity caused by Streptococcus pyogenes and Staphylococcus aureus, primary syphilis caused by Treponema pallidum, infections caused by Chlamydia trachomatis, nongonococcal urethritis caused by Ureaplasma urealyticum, and Legionnaires' disease caused by Legionella pneumophila.


Erythromycin is produced by a strain of Streptomyces erythraeus and belongs to the macrolide group of antibiotics. After absorption, erythromycin diffuses readily into most body fluids. In the absence of meningeal inflammation, low concentrations are normally achieved in the spinal fluid, but the passage of the drug across the blood-brain barrier increases in meningitis. Erythromycin is excreted in breast milk. The drug crosses the placental barrier, but fetal plasma levels are low. Erythromycin is not removed by peritoneal dialysis or hemodialysis.

Mechanism of Action

Erythromycin acts by penetrating the bacterial cell membrane and reversibly binding to the 50 S subunit of bacterial ribosomes or near the “P” or donor site so that binding of tRNA (transfer RNA) to the donor site is blocked. Translocation of peptides from the “A” or acceptor site to the “P” or donor site is prevented, and subsequent protein synthesis is inhibited. Erythromycin is effective only against actively dividing organisms. The exact mechanism by which erythmromycin reduces lesions of acne vulgaris is not fully known: however, the effect appears to be due in part to the antibacterial activity of the drug.


Orally administered erythromycin base and its salts are readily absorbed in the microbiologically active form. Topical application of the ophthalmic ointment to the eye may result in absorption into the cornea and aqueous humor.


Symptoms of overdose include diarrhea, nausea, stomach cramps, and vomiting.

Biotrnasformation / Drug Metabolism

Hepatic. Extensively metabolized - after oral administration, less than 5% of the administered dose can be recovered in the active form in the urine.


Erythromycin is contraindicated in patients with known hypersensitivity to this antibiotic. Erythromycin is contraindicated in patients taking terfenadine, astemizole, or cisapride. Topical Ery 2% Pads are contraindicated in those individuals who have shown hypersensitivity to any of its components.

Drug Interactions

Erythromycin use in patients who are receiving high doses of theophylline may be associated with an increase in serum theophylline levels and potential theophylline toxicity. In case of theophylline toxicity and/or elevated serum theophylline levels, the dose of theophylline should be reduced while the patient is receiving concomitant erythromycin therapy.

Concomitant administration of erythromycin and digoxin has been reported to result in elevated digoxin serum levels. There have been reports of increased anticoagulant effects when erythromycin and oral anticoagulants were used concomitantly. Increased anticoagulation effects due to interactions of erythromycin with various oral anticoagulents may be more pronounced in the elderly.

Concurrent use of erythromycin and ergotamine or dihydroergotamine has been associated in some patients with acute ergot toxicity characterized by severe peripheral vasospasm and dysesthesia.

Erythromycin has been reported to decrease the clearance of triazolam and midazolam and thus may increase the pharmacologic effect of these benzodiazepines.

The use of erythromycin in patients concurrently taking drugs metabolized by the cytochrome P450 system may be associated with elevations in serum levels of these other drugs. There have been reports of interactions of erythromycin with carbamazepine, cyclosporine, tacrolimus, hexobarbital, phenytoin, alfentanil, cisapride, disopyramide, lovastatin, bromocriptine, valproate, terfenadine, and astemizole. Serum concentrations of drugs metabolized by the cytochrome P450 system should be monitored closely in patients concurrently receiving erythromycin.

Erythromycin has been reported to significantly alter the metabolism of nonsedating antihistamines terfenadine and astemizole when taken concomitantly. Rare cases of serious cardiovascular adverse events, including electrocardiographic QT/QTc interval prolongation, cardiac arrest, torsades de pointes, and other ventricular arrhythmias have been observed. In addition, deaths have been reported rarely with concomitant administration of terfenadine and erythromycin.

There have been postmarketing reports of drug interactions when erythromycin is coadministered with cisapride, resulting in QT prolongation, cardiac arrythmias, ventricular tachycardia, ventricular fibrulation, and torsades de pointes, most like due to inhibition of hepatic metabolism of cisapride by erythromycin. Fatalities have been reported.

Patients receiving concomitant lovastatin and erythromycin should be carefully monitored; cases of rhabdomyolysis have been reported in seriously ill patients.

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