• Basic Info
• Top Questions
• Clinical Info

What is this medicine?

ISONIAZID is used to prevent or to treat tuberculosis. This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:

• diabetes
• HIV positive
• if you frequently drink alcohol-containing beverages
• kidney disease
• liver disease
• malnutrition
• tingling of the fingers or toes, or other nerve disorder
• an unusual or allergic reaction to isoniazid, other medicines, foods, dyes or preservatives
• pregnant or trying to get pregnant
• breast-feeding

How should I use this medicine?

Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. Take this medicine on an empty stomach, at least 30 minutes before or 2 hours after food. Do not take with food. Take your medicine at regular intervals. Do not take your medicine more often than directed. For your therapy to work as well as possible, take each dose exactly as prescribed. Do not skip doses or stop your medicine even if you feel better. Skipping doses may make the TB resistant to this medicine and other medicines. Do not stop taking except on your doctor's advice. Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed. Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once. NOTE: This medicine is only for you. Do not share this medicine with others.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medicine?

Do not take this medicine with any of the following medications:

• entacapone
• green tea
• levodopa
• MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate
• procarbazine
• ranolazine
• tolcapone

• acetaminophen
• alcohol
• antacids
• medicines for diabetes
• medicines for fungal infections like ketoconazole and itraconazole
• medicines for seizures like carbamazepine, phenobarbital, phenytoin, valproic acid
• theophylline
• zalcitabine

What should I watch for while using this medicine?

Visit your doctor or health care professional for regular check ups. You will need blood work done regularly. You may need to take vitamin supplements while on this medicine. Talk to your doctor about the foods you eat and the vitamins you take. Avoid antacids for 2 hours before and after taking a dose of this medicine. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks. If you are diabetic check your blood sugar as directed. Also, you may get a false-positive result for sugar in your urine. Talk with your doctor.