Recommended Dosage of Azithromycin for Bacterial Infections
For bacterial infections in adults, azithromycin is typically administered as 500 mg on day 1, followed by 250 mg once daily for days 2 through 5, or alternatively as 500 mg once daily for 3 days, depending on the infection type. 1
Standard Adult Dosing Regimens
For community-acquired pneumonia (mild severity), pharyngitis/tonsillitis (second-line therapy), and uncomplicated skin/skin structure infections: 500 mg as a single dose on day 1, followed by 250 mg once daily on days 2 through 5 1
For acute bacterial exacerbations of chronic obstructive pulmonary disease (mild to moderate) and acute bacterial sinusitis: 500 mg once daily for 3 days OR 500 mg as a single dose on day 1, followed by 250 mg once daily on days 2 through 5 1
For genital ulcer disease (chancroid) and non-gonococcal urethritis/cervicitis: One single 1 gram dose 1
For gonococcal urethritis and cervicitis: One single 2 gram dose 1
Pediatric Dosing Regimens
For acute otitis media: 30 mg/kg as a single dose OR 10 mg/kg once daily for 3 days OR 10 mg/kg on day 1 followed by 5 mg/kg/day on days 2 through 5 1
For acute bacterial sinusitis: 10 mg/kg once daily for 3 days 1
For community-acquired pneumonia: 10 mg/kg as a single dose on day 1 followed by 5 mg/kg on days 2 through 5 1
For pharyngitis/tonsillitis: 12 mg/kg once daily for 5 days 1, 2
Specific Infection-Based Recommendations
For community-acquired lower respiratory tract infections managed in the hospital: oral azithromycin 500 mg daily for 3 days OR 500 mg on day 1 then 250 mg daily for 5 days 3
For community-acquired pneumonia managed in the hospital: oral azithromycin 500 mg daily for 3 days OR 500 mg on day 1 then 250 mg daily for 5 days 3
For atypical pneumonia syndrome: a single 1.5 g dose has been shown to be as effective as 500 mg once daily for 3 days 4
For Mycobacterium avium complex (MAC) disease in HIV-infected children: azithromycin 5 mg/kg body weight (maximum 250 mg) by mouth daily plus ethambutol 3
Special Population Considerations
No dosage adjustment is recommended for patients with renal impairment (GFR ≤80 mL/min), though caution should be exercised in patients with severe renal impairment (GFR <10 mL/min) 1
No dosage adjustment recommendations can be made for patients with impaired hepatic function as pharmacokinetics in this population have not been established 1
No dosage adjustment is recommended based on age or gender 1
Clinical Efficacy and Tolerability
Azithromycin achieves clinically relevant concentrations at infection sites, is slowly eliminated from the body, and has few drug interactions 2
In clinical studies, a 3-day regimen of azithromycin (500 mg once daily) was as effective as a 10-day regimen of co-amoxiclav (625 mg three times daily) in treating lower respiratory tract infections 5
Azithromycin is generally well-tolerated with mostly mild to moderate gastrointestinal adverse events 2, 6
Important Considerations
Azithromycin can be taken with or without food, though absorption may be reduced by up to 50% when taken with a large meal 7
The long half-life of azithromycin (up to 5 days) allows for shorter treatment courses compared to other antibiotics 7
When treating streptococcal pharyngitis in children, a higher dose of 12 mg/kg/day for 5 days is recommended due to potential for recurrence of infection with lower dosing 2