Azithromycin is an antibiotic useful for the treatment of a number of bacterial infections. This includes middle ear infections, strep throat, pneumonia, traveler's diarrhea, and certain other intestinal infections. It may also be used for a number of sexually transmitted infections including chlamydia and gonorrhea infections. Along with other medications, it may also be used for malaria. It can be taken by mouth or intravenously with doses once per day.
Common side effects include nausea, vomiting, diarrhea and upset stomach. An allergic reaction such as anaphylaxis, QT prolongation, or a type of diarrhea caused by Clostridium difficile is possible. No harm has been found with its use during pregnancy. Its safety during breastfeeding is not confirmed, but it is likely safe. Azithromycin is an azalide, a type of macrolide antibiotic. It works by decreasing the production of protein, thus stopping bacterial growth.
Azithromycin was first discovered in 1980. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. It is available as a generic medication and is sold under many trade names worldwide. The wholesale cost in the developing world is about US$0.18 to US$2.98 per dose. In the United States it is about US$4 for a course of treatment as of 2018. In 2016 it was the 49th most prescribed medication in the United States with more than 15 million prescriptions.