How long does azithromycin work?

The standard answer is that azithromycin is actively fighting infection for 10 days during a course of normal therapy, which includes both the 3 and 5 day dosing of the medication. This answer is based on the drugs long half life, which results from its uptake by phagocytes. (Both 3 and 5 day dosing schedules result in a total of 1.5 grams of azithromycin being delivered to the patient.)