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Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.


(riff-AM-pin WITH eye-so-NYE-uh-zid)


WARNING: This medication has caused severe, even fatal, liver problems (e.g., hepatitis). Liver problems increase with age and with daily use of alcohol. Hepatitis can develop with use of this drug at any time during treatment. Stop using this medication and notify your doctor immediately if you develop unusual fatigue, weakness, loss of appetite, nausea, vomiting, dark urine, yellowing of the eyes or skin, or stomach or abdominal pain. Your doctor may decide to slowly restart isoniazid after these symptoms disappear and lab tests return to normal. People with active (acute) liver problems should not use this medication for preventative treatment until after the liver problems have stopped. Your doctor will monitor your liver function tests at least every month to discuss your progress.


This medication is used in the treatment of tuberculosis.

How To Use

Take this medication by mouth on an empty stomach (one hour before or two hours after meals) as directed. Take all this medication as prescribed. Do not skip doses or stop taking this without your doctor's approval. Stopping therapy too soon may result in ineffective treatment. For best results, take this medication at evenly spaced intervals throughout the day and night to keep your blood level constant. Antacids may reduce the absorption of rifampin. Take this drug at least one hour before taking any antacids.

Side Effects

Stomach upset, heartburn, gas, diarrhea, sore mouth, drowsiness, dizziness or flushing may occur the first several days as your body adjusts to the medication. If any of these effects continue or become bothersome, inform your doctor. This medication may cause urine, saliva, tears and sweat to turn red-orange in color. Do not be alarmed. This will disappear when the medication is stopped. Notify your doctor if you develop: weakness, unusual bruising or bleeding, headache, nausea, vomiting, yellowing of the eyes or skin, dark urine, pale stools, numbness or tingling of the hands or feet, changes in vision, confusion, memory trouble, fever, sore throat, fever, chills. In the unlikely event you have an allergic reaction to this drug, seek immediate medical attention. Symptoms of an allergic reaction include: rash, itching, swelling, dizziness, trouble breathing. If you notice other effects not listed above, contact your doctor or pharmacist.


Tell your doctor if you have: liver disease, kidney problems, blood disorders, history of alcohol use, allergies (especially drug allergies). Alcohol can reduce the effectiveness of this medication and increase side effects. Limit alcohol consumption while taking this medication. Use caution operating machinery or participating in activities requiring alertness if this medication makes you feel drowsy or dizzy. Soft contact lenses may be permanently discolored by this medication. This medication should be used only if clearly needed during pregnancy or while breast-feeding. Discuss the risks and benefits with your doctor.

Drug Interactions

This drug is not recommended for use with: delavirdine. Ask your doctor or pharmacist for more details. Inform your doctor about all the medicines you may use (both prescription and nonprescription) especially of: other MAO inhibitors (e.g., furazolidone, linezolid, moclobemide, phenelzine procarbazine, selegiline, isocarboxazid, tranylcypromine), adrenaline-like drugs (e.g., sympathomimetics such as ephedra, pseudoephedrine, phenylpropanolamine), serotonin-type drugs (including SSRI antidepressants and triptans such as sumatriptan), warfarin, oral medicines for diabetes, azole antifungals (e.g., itraconazole, ketoconazole), theophylline, halothane, verapamil, certain protease inhibitors (e.g., nelfinavir), corticosteroids, (e.g., prednisone), disopyramide, beta-blockers (e.g., metoprolol), isoniazid, digitoxin, quinidine, mexiletine, phenytoin, cyclosporine, zidovudine, live vaccines. It is very important that you follow special dietary restrictions in order to limit the amount of tyramine in your diet while you are taking this medicine. Foods and beverages high in tyramine should be avoided (see list below). Excessive amounts of coffee, chocolate, sour cream, or avocados have also produced symptoms of high blood pressure in some cases. High tyramine content foods include: aged cheeses (cheddar, camembert, emmenthaler, brie, stilton blue, gruyere, gouda, brick, bleu, roquefort, boursault, parmesan, romano, provolone, liederdranz, colby, edam), aged/dried/fermented/salted/smoked/pickled/processed meats and fish (includes bacon, summer sausage, liverwurst, hot dogs, corned beef, pepperoni, salami, bologna, ham, mortadella, pickled or dried herring), banana peel, beef and chicken liver (stored, not fresh), bouillon cubes, commercial gravies, concentrated yeast extracts (marmite), fava beans, Italian green beans, broad beans, fermented bean curd, homemade yeast-leavened bread, kim chee (Korean fermented cabbage), miso, orange pulp, overripe or spoiled fruits, packaged soups, red wine, sauerkraut, sherry, snow pea pods, sourdough bread, soy sauce, soya bean, soya bean paste, tap beer and ale, vermouth. Moderate-to-low tyramine content foods include: alcohol-free beer, avocados, bananas, bottled beer and ale, chocolate and products made with chocolate, coffee, cola, cultured dairy products (e.g. buttermilk, yogurt, sour cream), distilled spirits, eggplant, canned figs, fish roe (caviar), green bean pods, pate, peanuts, port wine, raisins, raspberries, red plums, spinach, tomatoes, white wine. Tell your doctor or pharmacist immediately if you notice symptoms of high blood pressure such as fast or slow heartbeat, vomiting, sweating or headache, chest pain, sudden vision changes, one-sided weakness or slurred speech. Contact your healthcare professional (e.g., doctor, pharmacist or dietician) for more information, including recommendations for your diet. Rifampin can decrease the effectiveness of oral contraceptives. Discuss the use of other birth control methods with your doctor. Also report drugs which cause drowsiness such as: sedatives, tranquilizers, psychiatric medicines, anti-seizure or anti-anxiety drugs, narcotic pain relievers, certain antihistamines (e.g., diphenhydramine). Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include nausea, vomiting, stomach pain, dizziness, slurred speech, blurred vision, unusually slow breathing, loss of consciousness, and seizures.


Laboratory tests will be done frequently to monitor the effectiveness of this medication and to prevent side effects. You may need to take pyridoxine (vitamin B-6) while taking this, ask your doctor. You should get regular eye exams also.

Missed Dose

Try to take each dose at the scheduled time. If you miss a dose, take it as soon as remembered; do not take it if it is near the time for the next dose, instead, skip the missed dose and resume your usual dosing schedule. Do not "double-up" the dose to catch up.


Store this medication at room temperature between 59 and 86 degrees F (15 and 30 degrees C), away from heat and light. Do not store in the bathroom. Keep this and all medications out of the reach of children.