Maximum Recommended Dose of Azithromycin
The maximum recommended dose of azithromycin is 500 mg per day for standard bacterial infections in adults, with the notable exception of a single 1 gram dose for chlamydial infections and certain other sexually transmitted infections. 1, 2
Standard Adult Maximum Dosing
For most bacterial infections, the maximum daily dose is 500 mg, typically given as 500 mg on day 1, followed by 250 mg daily for 4 additional days (total 5-day course). 1, 2, 3
A single 1 gram (1000 mg) dose is the maximum for single-dose regimens, specifically approved for non-gonococcal urethritis and cervicitis caused by Chlamydia trachomatis. 1, 2, 3
For severe community-acquired pneumonia requiring hospitalization, 500 mg IV daily is the maximum, given for 2-5 days followed by oral 500 mg daily to complete 7-10 days total. 3, 4
Pediatric Maximum Dosing
The maximum pediatric dose is 500 mg per day, calculated as 10 mg/kg on day 1 (maximum 500 mg), followed by 5 mg/kg once daily on days 2-5 (maximum 250 mg/day). 2, 3, 4
For streptococcal pharyngitis in children, higher doses of 12 mg/kg/day for 5 days (maximum 500 mg/day) are more effective than the standard 10 mg/kg regimen, with 60 mg/kg total course showing superior bacterial eradication compared to 30 mg/kg total course. 5, 6
For pertussis in infants under 6 months, 10 mg/kg once daily for 5 days is the maximum. 3
Special High-Dose Situations
For immunocompromised patients with babesiosis, doses up to 600-1000 mg daily may be used, representing the highest therapeutic doses in clinical practice. 2
For disseminated MAC disease in AIDS patients, 1200 mg once weekly is used for prophylaxis, though this is a weekly rather than daily maximum. 3
For bronchiectasis prophylaxis, 500 mg three times weekly is the maximum chronic dosing regimen. 3, 4
Critical Safety Considerations
Never exceed 500 mg per day for standard infections without specific indication, as higher doses increase risk of gastrointestinal adverse effects and QT prolongation. 3, 4
The 1 gram single dose should only be used for specific indications (chlamydia, certain travelers' diarrhea), not as a general approach to bacterial infections. 1, 2
Obtain baseline ECG before initiating therapy if QTc prolongation is a concern, particularly with doses ≥500 mg daily or in patients on other QT-prolonging medications. 3
Common Pitfalls to Avoid
Do not confuse total course dose with daily maximum dose: A 5-day course totaling 1500 mg (500 mg day 1, then 250 mg days 2-5) is standard, but the daily maximum remains 500 mg. 2, 3
Do not use the 1 gram single dose for streptococcal pharyngitis: This indication requires either the standard 5-day regimen or higher-dose regimens (12 mg/kg/day for 5 days in children). 1, 6
Avoid assuming all liquid formulations have the same concentration: Verify mg/mL strength before calculating doses, as concentrations vary between 100 mg/5 mL and 200 mg/5 mL. 2
Do not administer with aluminum- or magnesium-containing antacids simultaneously, as they reduce absorption by up to 50%; separate by at least 2 hours. 2, 4