Adults

Typical dosage is 500 mg once daily for 3 days, or 500 mg on day 1 followed by 250 mg once daily for 4 days. For specific STIs, a single 1000 mg dose may be given. Azinil 250 mg is often used in a longer course (e.g., 250 mg daily for 6 days).

Elderly

No specific dose adjustment is required for elderly patients with normal renal and hepatic function.

Renal_impairment

No dosage adjustment is needed for mild to moderate renal impairment (creatinine clearance >10-80 mL/min). Use with caution in severe renal impairment (creatinine clearance <10 mL/min).

Onset

Bactericidal effects typically begin within 2-3 hours.

Excretion

Primarily excreted unchanged in the bile; a small portion is excreted in the urine (about 6%).

Half life

Prolonged terminal elimination half-life of 68-72 hours, allowing for once-daily dosing.

Absorption

Rapidly absorbed from the gastrointestinal tract; bioavailability is approximately 37%. Peak plasma concentrations occur 2-3 hours after administration.

Metabolism

Undergoes minimal hepatic metabolism, primarily by N-demethylation.

Digoxin

May increase digoxin concentrations; monitor digoxin levels.

Warfarin

Potentiates the anticoagulant effect; monitor INR.

Nelfinavir

Increases azithromycin serum concentrations; no dose adjustment needed, but monitor for known adverse reactions.

QTc-prolonging drugs

Increased risk of cardiac arrhythmias; avoid co-administration if possible.

Antacids containing aluminum or magnesium

Reduce peak serum levels of azithromycin; take azithromycin at least 1 hour before or 2 hours after antacids.