Azithromycin is used to treat many different types of infections caused by bacteria, including infections of the lungs, sinus, throat, tonsils, skin, urinary tract, cervix, or genitals.

Azithromycin may also be used for purposes not listed in this medication guide.

You should not use azithromycin if you are allergic to it, or if you have ever had:

• jaundice or liver problems caused by taking azithromycin; or
• a severe allergic reaction to similar drugs such as clarithromycin, erythromycin, or telithromycin.

Azithromycin oral should not be used to treat pneumonia in people who have:

• cystic fibrosis;
• an infection after being in a hospital;
• an infection in the blood;
• a weak immune system (caused by diseases such as HIV/AIDS or cancer); or
• in older adults and those who are ill or debilitated.

Tell your doctor if you have ever had:

• pneumonia;
• liver or kidney disease;
• myasthenia gravis;
• low levels of potassium in your blood;
• a heart rhythm disorder; or
• long QT syndrome (in you or a family member).

It is not known whether this medicine is effective in treating genital ulcers in women.

Tell your doctor if you are pregnant or breastfeeding. Taking azithromycin while breastfeeding may cause diarrhea, vomiting, or rash in the nursing baby.

Azithromycin is not approved for use by anyone younger than 6 months old. Azithromycin should not be used to treat a throat or tonsil infection in a child younger than 2 years old.

Use Zithromax Z-Pak (Oral) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Get emergency medical help if you have signs of an allergic reaction (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, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes.

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, vomiting, loss of appetite, stomach pain (upper right side), tiredness, itching, 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 side effects may include:

• nausea, vomiting; or
• stomach pain.

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.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor before using anti-diarrhea medicine.

Azithromycin could make you sunburn more easily. Avoid sunlight or tanning beds. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.