Get emergency medical help if you have any of these signs of an allergic reaction to Zithromax: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have a serious side effect such as:

    *      diarrhea that is watery or bloody;
    *      chest pain, uneven heartbeats;
    *      nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
    *      fever, sore throat, and headache with a severe blistering, peeling, and red skin rash.

Less serious Zithromax side effects may include:

    *      mild nausea, vomiting, diarrhea, constipation;
    *      stomach pain or upset;
    *      dizziness, tired feeling, or headache;
    *      nervous feeling, sleep problems (insomnia);
    *      vaginal itching or discharge;
    *      mild itching or skin rash;
    *      ringing in your ears, problems with hearing; or
    *      decreased sense of taste or smell.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.