PRECAUTIONS: Tell your doctor if you have: other illnesses, allergies (especially drug allergies), liver disease, colitis or other stomach problems, kidney disease. Use of this medication for prolonged or repeated periods may result in a secondary infection (e.g., oral, bladder or vaginal yeast infection). Tell your doctor if you are pregnant before taking this medication. It is not known if azithromycin appears in breast milk. Consult with your doctor before breast-feeding.

DRUG INTERACTIONS: See also the How to Use section. Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: aluminum- and magnesium-containing antacids, digoxin, live vaccines, lovastatin, nelfinavir, warfarin. This medication may decrease the effectiveness of combination-type birth control pills. This can result in pregnancy. You may need to use an additional form of reliable birth control while using this medication. Consult your doctor or pharmacist for details. Other drugs besides azithromycin which may affect the heart rhythm (QTc prolongation in the EKG) include dofetilide, pimozide, procainamide, quinidine, sotalol, and sparfloxacin among others. QTc prolongation can infrequently result in serious, rarely fatal, irregular heartbeats. Consult your doctor or pharmacist for details. Ask for instructions about whether you need to stop any other QTc-prolonging drugs you may be using in order to minimize the risk of this effect. Do not start or stop any medicine without doctor or pharmacist approval.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly. Symptoms of overdose may include nausea, vomiting, and diarrhea.