Azithromycin (Zithromax®, Pfizer) is a commonly used antibiotic which is FDA-approved for treatment of acute otitis media, bacterial sinusitis, and community-acquired pneumonia in children. It binds to a ribosomal subunit of susceptible organisms and interferes with microbial protein synthesis.  It has demonstrated effectiveness in clinical studies against a number of gram-positive and gram-negative organisms.

Recent trials have focused on higher doses over fewer days to improve overall treatment completion and new uses, e.g., pertussis. The use of higher doses over fewer days is based on its good tissue penetration and long half-life (over 50 hours in children).  For example, in manufacturer-sponsored trials, the effectiveness of one or three-day courses of oral azithromycin compared favorably with a ten-day course of amoxicillin-clavulanate for otitis media.

Food does not interfere with the absorption of oral azithromycin (suspension, capsule or tablet).  The medication penetrates well into tissues, including tonsils and middle ear fluid.  It is generally well tolerated although diarrhea, abdominal pain, nausea/vomiting or headache were reported (up to six percent) in clinical trials. Severe allergic reactions, jaundice and nephritis have been reported.  Accepted oral dosing regimens for otitis media in children are: 1) 10 mg/kg single dose on day one, with 5 mg/kg daily for four more days, 2) 10 mg/kg once daily for three days, or 3) single 30 mg/kg. The recommended dose for treating bacterial sinusitis is 10 mg/kg once daily for three days.

(Buck M. Pediatr Pharmacotherapy 2005;11(4):1-4) -- J.O.