Indications

Erythromycin is the drug of choice in the following indications-

Alternative to a penicillin in penicillin-sensitive patients, penicillin-resistant staphylococcal infections, alternative to a tetracycline in mycoplasma pneumonia

Pertussis diphtheria-especially in treatment of the carrier state

Rheumatic fever prophylaxis

Chronic bronchitis

Otitis media

Chronic prostatitis.

Therapeutic Class

Anti-diarrhoeal Antimicrobial drugs, Macrolides

Pharmacology

Erythromycin inhibits microsomal protein synthesis in susceptible organisms by inhibiting the translocation process. Specific binding to the 50S subunit or 70S ribosome occurs in these organisms but there is no binding to the stable 80S mammalian ribosome. Erythromycin is active against many Grampositive bacteria, some Gram-negative bacteria and against mycoplasmas and chlamydia.

Dosage & Administration

Adults: The usual dose is 1-2 gm daily in divided doses. This may be increased up to 4 gm per day according to the severity of the infection.

Children: The usual regimen is 30-50 mg/kg/day. In severe cases the dose may be doubled.

Interaction

Theophylline: Intravenous theophylline reduces the mean steady state erythromycin concentration after oral dosing by 37%. The clearance of intravenous theophylline is reduced by 83% in subjects currently taking oral erythromycin.

Carbamazepine: Several patients receiving treatment with carbamazepine showed two or three fold increases in their steady state plasma concentrations when erythromycin was given.

Digoxin: 12% of patients receiving digoxin metabolize up to 40% of an oral dose into cardioinactive metabolites in their guts. This microbiological conversion may be inhibited by erythromycin , resulting in increases in the serum digoxin level of up to 200%.

Warfarin: There have been several case reports of prolongation of the prothrombin time and bleeding in patients on warfarin given erythromycin.

Ergotamine: A single case report describes ergotamine toxicity in a patient under treatment with ergotamine.

Contraindications

Erythomycin is contraindicated in patients hypersensitive to erythromycin.

Side Effects

Erythromycin is one of the safer antibiotics. Nausea, gastrointestinal disturbances and allergy being the commonest (0.5-5%) adverse effects.

Pregnancy & Lactation

There is no evidence that the use of erythromycin is hazardous in pregnancy though it does cross the placental barrier.

Precautions & Warnings

Erythromycin should be given with care in patients with impaired hepatic function.

Overdose Effects

In case of overdosage, Erythromycin should be discontinued. Overdosage should be handled with the prompt elimination of unabsorbed drug and all other appropriate measures should be instituted. Erythromycin is not removed by peritoneal dialysis or haemodialysis.

Reconstitution

Direction for reconstitution of suspension: Shake the bottle to loosen powder. Add 60 ml or 100 ml of boiled and cooled water to the dry powder of the bottle. For ease of preparation, add water to the bottle in two proportions. Shake well after each addition until all the powder is in suspension.

Note: Shake the suspension well before each use. Keep the bottle tightly closed. The reconstituted suspension should be stored in a cool and dry place, preferably in refrigerator and unused portion should be discarded after 7 days.

Storage Conditions

Keep below 25°C temperature, away from light & moisture. Keep out of the reach of children.