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What should I avoid while taking isoniazid and rifampin?

Do not wear contact lenses while taking isoniazid and rifampin. Rifampin may turn your tears, sweat, saliva, urine, feces, and contact lenses a red-orange color. This effect may be permanent on contact lenses.

This medication may decrease the effectiveness of birth control pills. Talk to your doctor about using another form of birth control during treatment. Avoid alcohol while taking isoniazid and rifampin. Alcohol will increase the risk of damage to your liver during treatment with this medication.

Use caution with the foods listed below. They can interact with isoniazid and rifampin and cause a reaction that includes a severe headache, large pupils, neck stiffness, nausea, vomiting, diarrhea, flushing, sweating, itching, irregular heartbeats, and chest. A reaction will not necessarily occur, but eat these foods with caution until you know if you will react to them. Call your doctor immediately if you experience any of these symptoms.

Eat the following foods with caution:

• cheeses, including american, blue, boursault, brick, brie, camembert, cheddar, emmenthaler, gruyere, mozzarella, parmesan, romano, roquefort, stilton, and swiss;

• sour cream and yogurt;

• beef or chicken liver, fish, meats prepared with tenderizer, bologna, pepperoni, salami, summer sausage, game meat, meat extracts, caviar, dried fish, herring, shrimp paste, and tuna;

• avocados, bananas, figs, raisins, and sauerkraut;

• soy sauce, miso soup, bean curd, and fava beans;

• yeast extracts;

• ginseng;

• chocolate;

• caffeine (coffee, tea, cola, etc.); and

• beer (alcoholic and nonalcoholic), red wine (especially Chianti), sherry, vermouth, and other distilled spirits.

What are the possible side effects of isoniazid and rifampin?

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 pain;

• 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 and 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.