Clarithromycin (kla-RITH-roe-mye-sin ) is used to treat bacterial infections in many different parts of the body. It works by killing bacteria or preventing their growth. It is also used to treat and prevent Mycobacterium avium complex (MAC) infection, and to treat duodenal ulcers caused by Helicobacter pylori. However, this medicine will not work for colds, flu, or other virus infections. Clarithromycin also may be used for other problems as determined by your doctor.

Clarithromycin is available only with your doctor's prescription.

Special precautions

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For Clarithromycin , the following should be considered:

Allergies - tell your doctor if you have ever had any unusual or allergic reaction to Clarithromycin or to any related medicines, such as erythromycin. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy - Clarithromycin has not been studied in pregnant women. However, studies in animals have shown that Clarithromycin causes birth defects and other problems. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding - Clarithromycin passes into breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast feeding. Mothers who are taking this medicine and who wish to breast feed should discuss this with their doctor.

Children - Studies on this medicine have not been done in children up to 6 months of age. In effective doses, the medicine has not been shown to cause different side effects or problems in children over the age of 6 months than it does in adults.

Older adults - this medicine has been tested in a limited number of elderly patients and has not been shown to cause different side effects or problems in older people than it does in younger adults.

• Other medicines - although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary.

Other medical problems - the presence of other medical problems may affect the use of Clarithromycin . Make sure you tell your doctor if you have any other medical problems, especially:

•  Kidney disease - Patients with severe kidney disease may have an increased chance of side effects

Side effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Check with your doctor as soon as possible if any of the following side effects occur:

•  Incidence less frequent

• Cough;  fever or chills;  hoarseness;  lower back or side pain ;  painful or difficult urination 

•  Rare

• Abdominal tenderness;  fever;  nausea and vomiting;  severe abdominal or stomach cramps and pain;  shortness of breath;  skin rash and itching;  unusual bleeding or bruising;  watery and severe diarrhea, which may also be bloody;  yellow eyes or skin 

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

•  Less common

• Acid or sour stomach;  belching;  bloated, full feeling;  change in sensation of taste;  diarrhea (mild);  excess air or gas in stomach or intestines;  headache ;  heartburn ;  indigestion ;  passing gas;  stomach discomfort, upset, or pain 

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Keep all appointments with your doctor and the laboratory.

Do not let anyone else take your medicine.