Isoniazid, pyrazinamide, and rifampin are antibiotics. They prevent tuberculous bacteria from multiplying in your body.

The combination of isoniazid, pyrazinamide, and rifampin is used to treat tuberculosis (TB).

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

Take this medication for the full prescribed length of time. Your symptoms may get better before your infection is completely cleared. Isoniazid, pyrazinamide, and rifampin will not treat a viral infection such as the common cold or flu.

Avoid drinking alcohol while taking isoniazid, pyrazinamide, and rifampin. Alcohol may increase your risk of liver damage.

Isoniazid, pyrazinamide, and rifampin can make birth control pills less effective. Ask your doctor about using a different method of birth control while taking isoniazid, pyrazinamide, and rifampin.

Avoid foods that are high in tyramine, listed in the "What should I avoid while taking isoniazid, pyrazinamide, and rifampin?" section of this leaflet. Tyramine can interact with this medication and cause unpleasant side effects.

You should not use this medication if you are allergic to isoniazid, pyrazinamide, or rifampin (Rifamate, Rifadin, Rimactane), or if you have:

• severe liver disease;

• active gout; or

• if you have ever had drug fever, chills, and arthritis caused by taking this medication.

If you have any of these other conditions, you may need a dose adjustment or special tests to safely use isoniazid, pyrazinamide, and rifampin:

• kidney disease;

• liver disease;

• HIV;

• porphyria;

• gout;

• diabetes; or

• if you drink alcohol daily.

FDA pregnancy category C. It is not known whether isoniazid, pyrazinamide, and rifampin is harmful to an unborn baby. Before taking this medication, tell your doctor if you are pregnant or plan to become pregnant during treatment.

Isoniazid, pyrazinamide, and rifampin can make birth control pills less effective. Ask your doctor about using a different method of birth control to prevent pregnancy while taking isoniazid, pyrazinamide, and rifampin.

Isoniazid, pyrazinamide, and rifampin can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.