Get emergency medical help if you have signs of an allergic reaction to azithromycin: (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).
Seek medical treatment if you have a serious drug reaction that can affect many parts of your body. Symptoms may include: skin rash, fever, swollen glands, flu-like symptoms, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes. This reaction may occur several weeks after you began using azithromycin.
Call your doctor at once if you have:
severe stomach pain, diarrhea that is watery or bloody;
fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out); or
liver problems - nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).
Call your doctor right away if a baby taking azithromycin becomes irritable or vomits while eating or nursing.
Older adults may be more likely to have side effects on heart rhythm, including a life-threatening fast heart rate.
Common azithromycin side effects may include:
diarrhea;
nausea, vomiting, stomach pain; or
headache.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Azithromycin side effects (more detail)
