Azithromycin Injection Adult Dose
For severe community-acquired pneumonia requiring hospitalization, administer azithromycin 500 mg IV once daily for 2-5 days, then transition to oral 500 mg daily to complete a total course of 7-10 days. 1
Standard IV Dosing for Hospitalized Patients
- The recommended IV dose is 500 mg once daily for patients with severe bacterial infections requiring parenteral therapy 1
- After clinical improvement (typically 2-5 days of IV therapy), switch to oral azithromycin 500 mg daily to complete the full treatment course 1
- The total duration of therapy (IV plus oral) should be 7-10 days for most severe respiratory infections 1
Alternative Dosing for Legionnaires' Disease
- For hospitalized patients with Legionnaires' disease, use 500 mg IV daily for 2-7 days, then switch to oral to complete 7-10 days total 2
- For outpatients with Legionnaires' disease, use oral therapy: 500 mg on day 1, followed by 250 mg daily for 4 days 2
Critical Administration Considerations
- Do not administer azithromycin IV as a bolus or intramuscular injection - it must be given as an IV infusion over at least 60 minutes to avoid local reactions 3
- Obtain baseline ECG before initiating therapy in patients with cardiac risk factors; avoid if QTc >450 ms (men) or >470 ms (women) 4, 1
- Check baseline liver function tests, especially if prolonged therapy is anticipated 1
Common Clinical Pitfalls
- Never use azithromycin as monotherapy for suspected gonococcal infections due to widespread resistance - must combine with ceftriaxone 4, 1
- Azithromycin is NOT first-line for streptococcal pharyngitis due to increasing macrolide resistance in Group A Streptococcus 4
- Separate administration from aluminum- or magnesium-containing antacids by at least 2 hours, as they reduce absorption by up to 50% 2, 4