According to MedlinePlus, azithromycin is an antibiotic prescribed for common bacterial infections, including sexually transmitted diseases; bronchitis; pneumonia; skin conditions; and ear, sinus and throat infections. It is also used to treat and prevent Mycobacterium avium complex, a lung infection common in those with the human immunodeficiency virus. Less common uses include treating gastrointestinal infections, pertussis, Legionnaires' disease and babesiosis, and preventing heart infections and sexually transmitted diseases.
MedlinePlus maintains that azithromycin works by preventing the growth of bacteria. It is ineffective against viruses. The medication is available as a tablet, liquid and extended-release liquid. All are taken by mouth once a day at the same time each day to treat infection. The tablets and regular liquid can be taken with food and are usually prescribed for one to five days. The extended-release liquid needs to be taken on an empty stomach and is usually prescribed as a single dose. When the tablets or regular liquid are prescribed to prevent infection, the standard dosage is once a week. The extended-release version is not typically used for infection prevention.
MedlinePlus states that azithromycin is similar to clarithromycin, erythromycin and telithromycin, and is contraindicated in patients with allergies to any of those medications. Common side effects include nausea, diarrhea, vomiting, stomach pain and headache. Serious side effects, such as heartbeat irregularities and dizziness, need to be reported to a medical professional.