isoniazid, pyrazinamide, and rifampin

Pronunciation: EYE soe NYE a zid, PIR a ZIN a mide, and rif AM pin

Brand: Rifater

What is the most important information I should know about this medicine?

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You should not use this medication if you have severe liver disease, an attack of gout, a history of fever/chills and joint pain or stiffness when taking isoniazid, or if you also take certain antiviral medicines to treat HIV.

Serious and sometimes fatal liver problems may occur during treatment with isoniazid, pyrazinamide, 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.

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

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Avoid drinking alcohol. It may increase your risk of liver damage while you are taking this medicine.

What is isoniazid, pyrazinamide, and rifampin?

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

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

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

What should I discuss with my healthcare provider before taking this medicine?

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You should not use this medication if you are allergic to isoniazid, pyrazinamide, or rifampin, or if you have:

  • severe liver disease;
  • an attack of gout;
  • a history of fever, chills, and joint pain or stiffness caused by taking isoniazid; or
  • if you also take certain antiviral medicines--atazanavir, darunavir, fosamprenavir, tipranavir, or saquinavir.

To make sure isoniazid, pyrazinamide, and rifampin is safe for you, tell your doctor if you have:

  • liver disease, cirrhosis, a history of alcoholism, or if you drink more than 3 alcoholic beverages per day;
  • gout;
  • diabetes;
  • kidney disease;
  • if you take phenytoin (Dilantin); or
  • if you take antiviral medication to treat HIV or hepatitis.
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FDA pregnancy category C. In animal studies, this medicine caused birth defects. However, it is not known whether these effects would occur in people. Taking this medicine during the last few weeks of pregnancy may increase your risk of bleeding during delivery. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.

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This medicine can make birth control pills less effective. Ask your doctor about using non hormonal birth control (condom, diaphragm with spermicide) to prevent pregnancy while taking this medicine.

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Isoniazid, pyrazinamide, and rifampin can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.

How should I take this medicine?

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Before and during your treatment with isoniazid, pyrazinamide, and rifampin, your doctor may perform tests to make sure your tuberculosis is not resistant to this medicine. During treatment you may need frequent blood tests to check your liver function, and eye examinations to check your vision.

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Take this medicine on an empty stomach, at least 1 hour before or 2 hours after a meal. Take each dose with a full glass of water.

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Use this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Isoniazid, pyrazinamide, and rifampin will not treat a viral infection such as the common cold or flu.

This medication can also cause unusual results with certain lab urine tests, and may cause you to have a false positive drug screening test. If you provide a urine sample for drug screening, tell the laboratory staff that you are taking isoniazid, pyrazinamide, and rifampin.

Your doctor may have you take extra vitamin B6 while you are taking isoniazid, pyrazinamide, and rifampin. Take only the amount of vitamin B6 that your doctor has prescribed.

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Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

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Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of isoniazid, pyrazinamide, and rifampin can be fatal, especially when this medicine is combined with alcohol.

The first signs of an overdose may include nausea, vomiting, stomach pain, lack of energy, headache, and itching. Later symptoms may include severe stomach pain, yellowing of your skin or eyes, brown or red-orange colored body fluids (tears, sweat, saliva, urine, stools), swelling in your face, fast heartbeats, seizures (convulsions) or loss of consciousness.

What should I avoid while taking this medicine?

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Avoid drinking alcohol. It may increase your risk of liver damage while you are taking this medicine.

Avoid taking an antacid within 1 hour before or after you take isoniazid, pyrazinamide, and rifampin. Some antacids can make it harder for your body to absorb isoniazid, pyrazinamide, and rifampin.

Do not wear soft contact lenses while taking isoniazid, pyrazinamide, and rifampin. This medicine may turn certain body fluids a red color (including tears, saliva, urine, and sweat). While this is a harmless side effect, it may permanently stain contact lenses.

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Avoid foods that are high in tyramine or histamine, listed below. Tyramine or histamine can interact with this medication and cause unpleasant side effects. These foods include:

  • beer (alcoholic and nonalcoholic), wine (especially red wine);
  • cheese, especially aged or processed cheeses (American, blue, brie, cheddar, gruyere, mozzarella, parmesan, romano, Swiss, and others);
  • sour cream and yogurt;
  • tuna, skipjack, pickled or smoked fish, anchovies, dried fish, herring, caviar, shrimp paste, or other tropical fish;
  • soy sauce, miso soup, bean curd, fava beans; or
  • yeast extracts.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, stop taking isoniazid, pyrazinamide, and rifampin and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

What are the possible side effects of this medicine?

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Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

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Isoniazid, pyrazinamide, and rifampin can cause severe liver symptoms, especially in people who are 35 and older. Call your doctor at once if you have any of these early signs of liver damage: nausea, vomiting, upper stomach pain, tired feeling, or loss of appetite.

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Also tell your doctor right away if you have:

  • signs of liver or pancreas problems --dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes), severe pain in your upper stomach spreading to your back;
  • side effects on the brain or nervous system --vision problems, pain behind your eyes, unusual thoughts or behavior, seizure (convulsions);
  • blood cell disorders --fever, chills or other flu symptoms, pale skin, confusion or weakness, easy bruising, unusual bleeding;
  • joint pain or swelling;
  • severe skin rash;
  • little or no urinating;
  • diarrhea that is watery or bloody; or
  • shortness of breath, feeling like you might pass out.

Common side effects may include:

  • numbness, tingling, or burning pain in your hands or feet;
  • mild nausea or decreased appetite;
  • mild rash or itching; or
  • mild joint or muscle pain.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect this medicine?

Many drugs can interact with isoniazid, pyrazinamide, and rifampin. Not all possible interactions are listed here. Tell your doctor about all your medications and any you start or stop using during treatment with isoniazid, pyrazinamide, and rifampin, especially:

  • antifungal medication--fluconazole, itraconazole, ketoconazole, voriconazole;
  • birth control pills or hormone replacement therapy;
  • a blood thinner (warfarin, Coumadin) or other medication to prevent blood clots (clopidogrel, dabigatran, Plavix, Pradaxa, rivaroxaban, ticagrelor, and others);
  • vitamin D; or
  • steroids (prednisone and others) or thyroid medication.

This list is not complete and many other drugs can interact with isoniazid, pyrazinamide, and rifampin. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.

Where can I get more information?

Your pharmacist can provide more information about isoniazid, pyrazinamide, and rifampin.


Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

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