• Basic Info
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What is isoniazid/pyrazinamide/rifampin?
Isoniazid, pyrazinamide, and rifampin are antibiotics. They prevent tuberculous bacteria from multiplying in your body. Isoniazid, pyrazinamide, and rifampin are used together to treat tuberculosis (TB). Isoniazid/pyrazinamide/rifampin may also be used for purposes other than those listed in this medication guide.

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What are the possible side effects of isoniazid/pyrazinamide/rifampin?

If you experience any of the following serious side effects, stop taking isoniazid/pyrazinamide/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;

• difficult or painful urination;

• numbness or tingling in your hands or feet;

• muscle or bone pain;

• painful or swollen joints;

• worsening gout;

• seizures;

• blurred vision;

• fever, chills, or a sore throat;

• a headache;

• a rash or itching; or

• confusion or abnormal behavior.

Other, less serious side effects may be more likely to occur. Continue to take isoniazid/pyrazinamide/rifampin and talk to your doctor if you experience

• red-orange coloration of tears, sweat, saliva, urine, or feces; or

• mild tiredness or weakness.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

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How should I take isoniazid/pyrazinamide/rifampin?
Take isoniazid/pyrazinamide/rifampin exactly as directed by your doctor. However, if you do not understand these instructions, ask your pharmacist, nurse, or doctor to explain them to you. Take each dose with a full glass (8 ounces) of water. Take isoniazid/pyrazinamide/rifampin on an empty stomach 1 hour before or 2 hours after a meal. Take all of the isoniazid/pyrazinamide/rifampin that has been prescribed for you even if you begin to feel better. Your symptoms may begin to improve before the infection is completely treated.

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What is the most important information I should know about isoniazid/pyrazinamide/rifampin?
Take all of the isoniazid/pyrazinamide/rifampin that has been prescribed for you even if you begin to feel better. Your symptoms may begin to improve before the infection is completely treated. Avoid alcohol while taking isoniazid/pyrazinamide/rifampin. Alcohol will increase the risk of damage to your liver during treatment with this medication. Call your doctor immediately if you experience a fever, chills, a sore throat, muscle and bone pain, painful or swollen joints, a headache, excessive tiredness or weakness, numbness or tingling in your hands or feet, loss of appetite, nausea and vomiting, yellowing of your skin or eyes, darkening of your urine, unusual bleeding or bruising, a rash, or itching.

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What happens if I miss a dose?
Take the missed dose as soon as you remember. If it is almost time for your next regularly scheduled dose, skip the missed dose and take the next one as directed. Do not take a double dose of this medication.

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What other drugs will affect isoniazid/pyrazinamide/rifampin?
Before taking isoniazid/pyrazinamide/rifampin, tell your doctor if you are taking any of the following drugs: antacids. Aluminum salts will decrease the action of isoniazid. Do not take antacids that contain aluminum for 1 to 2 full hours before or after taking a dose of isoniazid. allopurinol (Zyloprim). The effects of allopurinol may be decreased by pyrazinamide. ketoconazole (Nizoral), itraconazole (Sporanox), or fluconazole (Diflucan). Isoniazid/pyrazinamide/rifampin may decrease the action of the antifungal medicines. Therefore, a fungal infection may not be adequately treated.

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Can I take this if I am pregnant or trying to get pregnant or if I am breastfeeding?

It is not known whether isoniazid/pyrazinamide/rifampin will harm an unborn baby. Do not take this medication without first talking to your doctor if you are pregnant.

It is also not known whether isoniazid/pyrazinamide/rifampin will harm a nursing baby. Do not take this medication without first talking to your doctor if you are breast-feeding a baby.

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What does my medication look like?
Isoniazid/pyrazinamide/rifampin is available with a prescription under the brand name Rifater. Other brand or generic formulations may also be available. Ask your pharmacist any questions you have about this medication, especially if it is new to you. Rifater 50 mg isoniazid/300 mg pyrazinamide/120 mg rifampin--round, light-beige tablets

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What happens if I overdose?
Seek emergency medical attention. Symptoms of an isoniazid/pyrazinamide/rifampin overdose include nausea, vomiting, abdominal pain, tiredness, dizziness, slurring of speech, yellow skin or eyes, blurred vision, visual hallucinations, seizures, coma, and death.

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Who should not take isoniazid/pyrazinamide/rifampin?
Before taking this medication, tell your doctor if you have ever had an allergic reaction; kidney disease; liver disease; porphyria; gout; or diabetes mellitus. You may not be able to take isoniazid/pyrazinamide/rifampin, or you may require a lower dose or special monitoring during treatment if you have any of the conditions listed above. It is not known whether isoniazid/pyrazinamide/rifampin will harm an unborn baby. Do not take this medication without first talking to your doctor if you are pregnant.

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Can I stop taking the medication if I feel better?
If you have been diagnosed with a disease for which an antibiotic is needed, you must complete the prescribed course of treatment. Even if you start to feel better, do not skip any doses and remember to take the medication until it is all gone.

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I am on so many medications; do I have to take them all?
This is called polypharmacy—many different medications being used at the same time by one person. Sometimes, being on multiple medications is acceptable and appropriate but at other times it may be problematic. If you are receiving your medications from multiple physicians you need to ensure that they all know what medications you are taking. The best way to do this is to make a list of all the medications you are currently using, including all nutritional supplements, homeopathic remedies, vitamins and over-the-counter drugs (if possible, also include all the diseases you have been diagnosed with). Give a copy to every doctor who takes care of you so they have it on file, this way they can avoid duplicating medications and perhaps even try to consolidate some. After every doctor's visit remember to update the list accordingly. Also, as much as you possibly can, try to use the same pharmacy to fill all your prescriptions, this way any potential drug interactions can be caught and averted.

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