Adults

Rarely used for adults in suspension form; adult dosage for azithromycin (as tablets/capsules) is typically 500 mg once daily for 3 days, or 500 mg on day 1 followed by 250 mg once daily for 4 days.

Elderly

Similar to adult dosage for azithromycin; no dose adjustment is generally required for elderly patients with normal renal and hepatic function. For suspension, follow pediatric guidelines if applicable for specific indications.

Renal_impairment

No dosage adjustment needed for mild to moderate renal impairment (creatinine clearance >10 mL/min). Caution is advised in severe renal impairment.

Onset

Onset of action typically occurs within 1-2 hours after administration.

Excretion

The primary route of excretion is biliary, with a small portion (approximately 6-11%) excreted unchanged in the urine over 72 hours.

Half life

The terminal elimination half-life is prolonged, ranging from 2 to 4 days, allowing for once-daily dosing.

Absorption

Rapidly absorbed from the gastrointestinal tract, but bioavailability is approximately 37% due to extensive tissue distribution. Absorption is generally unaffected by food for the suspension.

Metabolism

Primarily metabolized in the liver, but limited metabolism occurs. It undergoes demethylation in the liver.

Digoxin

May increase serum digoxin levels. Monitor digoxin levels if co-administered.

Warfarin

May enhance the anticoagulant effects of warfarin. Close monitoring of prothrombin time is recommended.

Nelfinavir

Increased azithromycin serum concentrations. No dosage adjustment is recommended.

Antacids (containing aluminum or magnesium)

Decreased peak plasma concentration of azithromycin when co-administered. Administer azithromycin at least 1 hour before or 2 hours after antacids.