Zithromax is an antibiotic related to erythromycin. It is prescribed for adults to treat certain mild to moderate skin infections; upper and lower respiratory tract infections, including pharyngitis (strep throat), tonsillitis, and pneumonia; sexually transmitted infections of the cervix or urinary tract; and genital ulcer disease in men. In children, Zithromax is used to treat middle ear infection, pneumonia, tonsillitis, and strep throat.

There is a possibility of rare but very serious reactions to Zithromax, including angioedema (swelling of the face, lips, and neck that impedes speaking, swallowing, and breathing), anaphylaxis (a violent, even fatal allergic reaction), and serious skin diseases. If you develop these symptoms, stop taking Zithromax and call your doctor immediately.

How should you take this medication?

Take Zithromax capsules or oral suspension at least 1 hour before or 2 hours after a meal. Zithromax tablets can be taken with or without food. Do not take any form with an antacid that contains aluminum or magnesium, such as Di-Gel, Gelusil, Maalox, and others.

If you are using single-dose packets of Zithromax powder for oral suspension, mix the entire contents of each packet with 2 ounces of water, drink immediately, then add an additional 2 ounces of water, mix again, and drink to make sure you've taken the entire dose. When giving the pediatric suspension, shake the bottle thoroughly before each use and measure the dose with the supplied calibrated dropper. Use the pediatric suspension within 10 days and throw out any that remains.

Be sure to take all the drug prescribed. If you stop taking Zithromax too soon, some germs may survive and the illness may return.

If you miss a dose...

Take the forgotten dose as soon as you remember. If you don't remember until the next day, skip the dose and go back to your regular schedule. Never try to "catch up" by doubling the dose.

Storage instructions...

Zithromax should be stored at room temperature.

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Zithromax.

More common side effects may include:

Abdominal pain, diarrhea or loose stools, nausea or vomiting

Less common side effects may include:

Blood in the stools, chest pain, dizziness, drowsiness, fatigue, gas, headache, heart palpitations, indigestion, jaundice (yellowing of the skin and the whites of the eyes), kidney infection, light sensitivity, rash, severe allergic reaction including swelling (as in hives), vaginal inflammation, vertigo, yeast infection

Other uncommon side effects sometimes seen in children include:

Agitation, constipation, feeling of illness, fever, insomnia, loss of appetite, nervousness, overactivity, pinkeye, stomach inflammation

The single large dose of Zithromax that is prescribed to treat sexually transmitted infection of the cervix or urinary tract is more likely to cause stomach and bowel side effects than the smaller doses prescribed for a skin or respiratory tract infection.

Do not take Zithromax if you have ever had an allergic reaction to it or to similar antibiotics such as erythromycin (E.E.S., PCE, and others).

Like certain other antibiotics, Zithromax may cause a potentially life-threatening form of diarrhea called pseudomembranous colitis. Pseudomembranous colitis may clear up spontaneously when the drug is stopped; if it doesn't, hospital treatment may be required. If you develop diarrhea, check with your doctor immediately.

If you have a liver problem, your doctor should monitor you very carefully while you are taking Zithromax.

If Zithromax is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Zithromax with antacids containing aluminum or magnesium, such as Maalox and Mylanta.

The following interactions can occur with erythromycin, a similar drug.

If you are pregnant or plan to become pregnant, inform your doctor immediately. You should take Zithromax during pregnancy only if it is clearly needed. It is not known whether Zithromax can make its way into breast milk. If the drug is essential to your health, your doctor may advise you to stop breastfeeding until your treatment is finished.

ADULTS

Respiratory Diseases, Tonsillitis, Strep Throat, and Skin Infections
The usual dose of Zithromax is 500 milligrams in a single dose the first day. This is followed by 250 milligrams once daily for the next 4 days.

Genital Ulcer Disease
The usual dose is a single gram (1,000 milligrams) one time only.

Sexually Transmitted Diseases
The usual dose is a single 2-gram (2,000 milligrams) dose.

CHILDREN

Middle Ear Infection and Pneumonia
For children aged 6 months and up, the usual dose is 10 milligrams of Zithromax suspension per 2.2 pounds of body weight in a single dose the first day, followed by 5 milligrams per 2.2 pounds for the next 4 days.

Strep Throat and Tonsillitis
For children aged 2 years and up, the usual dose is 12 milligrams per 2.2 pounds of body weight once daily for 5 days.

Although no specific information on Zithromax overdose is available, any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical attention immediately.