Enteric coated tablets, 250 mg (as stearate or ethylsuccinate)
Oral suspension, 125 mg (as stearate or ethylsuccinate)/5 ml

Erythromycin is a macrolide antimicrobial produced by Streptomyces erythreus. It has selective bacteriostatic activity against both streptococci and staphylococci and some Gram-positive bacilli. Because it is inactivated by gastric juices, oral formulations are enteric-coated. It diffuses rapidly into all tissues except the brain and cerebrospinal fluid, and readily crosses the placental barrier. The plasma half life is approximately 90 minutes. It is partially demethylated in the liver and excreted largely via the bile and faeces.

Uses: Streptococcal pharyngitis in penicillin-allergic patients.

Dosage:
Primary prophylaxis of rheumatic fever

Adults: 40 mg/kg/day (max. 1.5 g/day), 3 times daily.

Children: 20-40 mg/kg/day (max. 1.0 g/day) 3 times daily.

Secondary prophylaxis of rheumatic fever

250 mg twice daily.

Contraindications: Known hypersensitivity to erythromycin.

Precautions: Hepatic function should be monitored in patients with a previous history of liver disease.

Adverse effects: Erythromycin is well tolerated by most patients at the dosages suggested. Large oral doses may produce nausea, vomiting and diarrhoea.

Cholestatic hepatitis, which may present with symptoms suggestive of acute cholecystitis, occasionally complicates prolonged courses of treatment. Symptoms resolve rapidly when the drug is withdrawn.

Anaphylaxis and other hypersensitivity reactions are rare.

Drug interactions: Erythromycin, chloramphenicol, and clindamycin have a similar bacteriostatic action and may be antagonistic when administered together. Erythromycin decreases the rate of metabolism of carbamazepine and warfarin in the liver to a degree that can warrant readjustment of dosage.

Storage: Capsules and tablets should be stored in tightly closed containers.