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(rifampin and isoniazid) Capsules USP
Severe and sometimes fatal hepatitis associated with isoniazid therapy may occur and may develop even after many months of treatment. The risk of developing hepatitis is age related. Approximate case rates by age are: 0 per 1,000 for persons under 20 years of age, 3 per 1,000 for persons in the 20-34 year age group, 12 per 1,000 for persons in the 35-49 year age group, 23 per 1,000 for persons in the 50-64 year age group, and 8 per 1,000 for persons over 65 years of age. The risk of hepatitis is increased with daily consumption of alcohol. Precise data to provide a fatality rate for isoniazid-related hepatitis is not available; however, in a U.S. Public Health Service Surveillance Study of 13,838 persons taking isoniazid, there were 8 deaths among 174 cases of hepatitis.
Therefore, patients given isoniazid should be carefully monitored and interviewed at monthly intervals. Serum transaminase concentration becomes elevated in about 10-20 percent of patients, usually during the first few months of therapy, but it can occur at any time. Usually enzyme levels return to normal despite continuance of drug, but in some cases progressive liver dysfunction occurs. Patients should be instructed to report immediately any of the prodromal symptoms of hepatitis, such as fatigue, weakness, malaise, anorexia, nausea, or vomiting. If these symptoms appear or if signs suggestive of hepatic damage are detected, isoniazid should be discontinued promptly, since continued use of the drug in these cases has been reported to cause a more severe form of liver damage.
Patients with tuberculosis should be given appropriate treatment with alternative drugs. If isoniazid must be reinstituted, it should be reinstituted only after symptoms and laboratory abnormalities have cleared. The drug should be restarted in very small and gradually increasing doses and should be withdrawn immediately if there is any indication of recurrent liver involvement. Treatment should be deferred in persons with acute hepatic diseases.
RIFAMATE (rifampin and isoniazid) is a combination capsule containing 300 mg rifampin and 150 mg isoniazid. The capsules also contain as inactive ingredients: colloidal silicon dioxide, FD&C Blue No. 1, FD&C Red No. 40, gelatin, magnesium stearate, sodium starch glycolate, and titanium dioxide.
Rifampin is a semisynthetic antibiotic derivative of rifamycin B. The chemical name for rifampin is 3-(4-methyl-1-piperazinyliminomethyl) rifamycin SV.
Isoniazid is the hydrazide of isonicotinic acid. It exists as colorless or white crystals or as a white, crystalline powder that is water soluble, odorless, and slowly affected by exposure to air and light.
What are the possible side effects of isoniazid and rifampin (Rifamate)?
If you experience any of the following serious side effects, stop taking isoniazid and rifampin and seek emergency medical attention or contact your doctor immediately:
- an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);
- excessive tiredness or weakness;
- nausea, vomiting, diarrhea, or loss of appetite;
- yellow skin or eyes;
- unusual bruising or bleeding;
- dark urine;
- little or no urine;
- numbness or tingling in your hands or feet;
- muscle or bone...
What are the precautions when taking rifampin and isoniazid (Rifamate)?
See also Warning section.
Before taking this product, tell your doctor or pharmacist if you are allergic to rifampin or isoniazid; or to other rifamycins (such as rifabutin, rifapentine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: previous severe reaction from isoniazid (such as liver disease), liver disease, kidney disease, alcohol use, HIV infection, diabetes, numbness/tingling of arms/legs (peripheral neuropathy), recent childbirth, a certain blood disorder (porphyria).
Before having surgery, tell your doctor or dentist about all the...
Last reviewed on RxList: 2/24/2009
This monograph has been modified to include the generic and brand name in many instances.
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