Hello, azithromycin is taken for a limited time only because it acts even for days after the last dose. You haven t described your problem or your current symptoms, so I can t give you a very specific answer. I ll try to explain what might have happened though. Although the antibiotic acts for a long time, the infection needs some time to heal completely. Sometimes the infection may be caused by viruses, so the antibiotics have no effect on it. Your improvement could be related to other factors like having taken paracetamol (acetaminophen) for example. I ll be glad to comment on your situation if you d like to provide more details! Kind Regards!