IsonaRif

Isoniazid and rifampin are antibiotics that fight bacteria.

Isoniazid and rifampin is a combination medicine used to treat tuberculosis (TB).

Isoniazid and rifampin may also be used for purposes not listed in this medication guide.

You should not use isoniazid and rifampin if you have active liver disease (including hepatitis or cirrhosis), or a history of liver problems caused by taking isoniazid.

Serious and sometimes fatal liver problems may occur during treatment with isoniazid and rifampin or after you stop taking this medication, even months after stopping. The risk of liver problems is highest in adults between the ages of 35 and 65. Your liver function may need to be checked every month while you are taking this medicine.

Call your doctor right away if you have: nausea, upper stomach pain, loss of appetite, and feeling weak or tired.

Avoid drinking alcohol. It may increase your risk of liver damage while you are taking isoniazid and rifampin.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Do not wear soft contact lenses while taking isoniazid and rifampin. Rifampin may turn your tears a red-orange color. This effect could permanently discolor soft contact lenses.

Avoid drinking alcohol. It may increase your risk of liver damage while you are taking isoniazid and rifampin.

It is very important that your doctor check your progress at regular visits. In addition, you should check with your doctor immediately if blurred vision or loss of vision, with or without eye pain, occurs during treatment. He or she may want you to have your eyes checked by an ophthalmologist (eye doctor).

If your symptoms do not improve within 2 to 3 weeks, or if they become worse, check with your doctor.

Oral contraceptives (birth control pills) containing estrogen may not work properly if you take them while you are taking rifampin and isoniazid combination. Unplanned pregnancies may occur. You should use a different means of birth control while you are taking this medicine. If you have any questions about this, check with your health care professional.

Liver problems may be more likely to occur if you drink alcoholic beverages regularly while you are taking this medicine. Also, the regular use of alcohol may keep this medicine from working properly. Therefore, you should strictly limit the amount of alcoholic beverages you drink while you are taking this medicine.

Certain foods such as cheese (Swiss or Cheshire) or fish (tuna, skipjack, or Sardinella) may rarely cause reactions in some patients taking isoniazid-containing medicines. Check with your doctor if redness or itching of the skin, hot feeling, fast or pounding heartbeat, sweating, chills or clammy feeling, headache, or lightheadedness occurs after eating these foods while you are taking this medicine.

This medicine will cause the urine, stool, saliva, sputum, sweat, and tears to turn reddish-orange to reddish-brown. This is to be expected while you are taking this medicine. This effect may cause soft contact lenses to become permanently discolored. Standard cleaning solutions may not take out all the discoloration. Therefore, it is best not to wear soft contact lenses while taking this medicine. This condition will return to normal once you stop taking this medicine. Hard contact lenses are not discolored by this medicine. If you have any questions about this, check with your doctor.

If this medicine causes you to feel very tired or very weak; or causes clumsiness; unsteadiness; a loss of appetite; nausea; numbness, tingling, burning, or pain in the hands and feet; or vomiting, stop taking it and check with your doctor immediately. These may be early warning symptoms of more serious liver or nerve problems that could develop later.

Rifampin and isoniazid combination may cause blood problems. These problems may result in a greater chance of certain infections, slow healing, and bleeding of the gums. Therefore, you should be careful when using regular toothbrushes, dental floss, and toothpicks. Dental work should be delayed until your blood counts have returned to normal. Check with your medical doctor or dentist if you have any questions about proper oral hygiene (mouth care) during treatment.

Rx Only

WARNING

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.

Rifampin/Isoniazid is a combination capsule containing 300 mg rifampin and 150 mg isoniazid. Each capsule for oral administration, contain the following inactive ingredients: colloidal silicon dioxide, corn starch, lactose monohydrate,magnesium stearate, and pregelatinized starch.

Capsule shell contains: FD&C blue #1, FD&C red #40, gelatin and titanium dioxide.

The printing ink contains: ammonium hydroxide, isopropyl alcohol, N-butyl alcohol, pharmaceutical glaze, propylene glycol, simethicone, 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 powderthat is water soluble, odorless and slowly affected by exposure to air and light.

In general, therapy should be continued until bacterial conversion and maximal improvement have occurred.

Adults: Two Rifampin and Isoniazid Capsules, USP (600 mg rifampin, 300 mg isoniazid) once daily, administeredone hour before or two hours after a meal.

Concomitant administration of pyridoxine (B6) is recommended in the malnourished, in those predisposed toneuropathy (e.g., diabetic), and in adolescents.

Susceptibility Testing, Rifampin

Rifampin susceptibility powders are available for both direct and indirect methods of determining the susceptibility of strains of mycobacteria. The MIC's of susceptible clinical isolates when determined in 7H10 or other non-eggcontainingmedia have ranged from 0.1 to 2 mcg/mL. Quantitative methods that require measurement of zonediameters give the most precise estimates of antibiotic susceptibility. One such procedure has been recommendedfor use with discs for testing susceptibility to rifampin. Interpretations correlate zone diameters from the disc testwith MIC (minimal inhibitory concentration) values for rifampin.