Azithromycin API, despite its efficiency and low risk factors, also has side effects. That is why doctors are very cautious when prescribing this type of macrolide antibiotics. Some of the known side effects of Azithromycin API are nausea, abdominal discomfort, mild diarrhea, headache and dizziness. Also, people with liver problems should be cautious in medicating with Azithromycin API. In addition to that, a person must be at least 6 years of age and weigh at least 55 pounds before he or she is allowed to take this antibiotic. People who are allergic to macrolide antibiotics must not take Azithromycin API.