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Drug Info for isoniazid

Isoniazid is used with other drugs to treat tuberculosis (TB; a serious infection that affects the lungs and sometimes other parts of the body). Isoniazid is also used with other drugs to treat people with latent (resting or nongrowing) TB including those in close contact with people who have active TB, a positive tuberculin skin test, human immunodeficiency virus (HIV), and those with pulmonary fibrosis (scarring of the lungs with an unknown cause). Isoniazid is in a class of medications called antituberculosis agents. It works by killing the bacteria that cause tuberculosis.

Isoniazid is a generic drug used treat patients with Tuberculosis (TB). The average cost of Isoniazid is around $15 for a supply of 30, 300 mg oral tablets. You can use our OptionRx savings offer to get an average Isoniazid discount of up to 80% off of the retail price at participating pharmacies near you.

Your doctor will tell you how much medicine to take and how often. It is very important to take this medicine on a regular schedule.

You may need to take isoniazid for several weeks or months. Keep taking it even if you have no symptoms. Your doctor will tell you when you can stop taking it.

Take on an empty stomach (1 hour before or 2 hours after a meal). May be taken with food to avoid stomach upset.

Shake the oral liquid well just before each use. Measure the dose using a marked measuring spoon or medicine cup.

You should not use this medicine if you have ever had an allergic reaction to isoniazid or reactions such as fever, chills, or arthritis from taking this medicine. You should not use isoniazid if you have liver damage from taking it before, or if you have severe liver disease of any type.

If you are pregnant or breastfeeding, talk to your doctor before taking this medicine.

Check with your doctor before taking if you have kidney or liver disease, or if you are being treated for seizures.

Isoniazid can cause liver problems. It is very important that you see your doctor on a regular schedule and have blood tests done as ordered.

Isoniazid can affect the results of some urine sugar tests. If you have diabetes do not change your medicine or diet unless you have checked with your doctor.

If you notice tingling, numbness, or pain in your hands or feet, contact your doctor.


Do not drink alcohol while taking isoniazid.

Make sure your doctor knows if you are taking blood thinners (such as Coumadin®), birth control pills, Dilantin®, or Antabuse®.

If you take antacids (such as Mylanta®, Maalox®, or Amphojel®), wait at least 1 hour after taking them before taking your isoniazid dose.

Foods such as cheese (Swiss, Cheshire, or Gruyere) or fish (tuna or skipjack) may cause headache, flushing, pounding heartbeat, sweating, dizziness, chills, or diarrhea. If you have these symptoms, call your doctor.

If you notice tingling, numbness, or pain in your hands or feet, contact your doctor.

  • Yellow skin or eyes
  • Dark or amber-colored urine
  • Weakness
  • Blurred vision, eye pain
  • Severe stomach pain, nausea and vomiting
  • Fever
  • Diarrhea
  • Stomach pain
Frequently Asked Questions

Isoniazid is an antibiotic medication that comes in tablet form, and it is used to treat patients with Tuberculosis (TB). This medication also prevents Tuberculosis (TB).

Isoniazid is available under the brand name Nydrazid. Consult with your doctor for more information about these drugs and to determine the best treatment for you.

The average Isoniazid price without insurance ranges from between about $13 and $362, depending on dosage, supply needed, and pharmacy location.

Isoniazid is a generic drug. A similar brand-name drug is Nydrazid. Our free coupon may be used for savings on Isoniazid and alternative brand-name drugs for savings of up to 80%.

Isoniazid oral tablets are available in the following strengths: 100 mg and 300 mg. Isoniazid is also available as an intramuscular solution and oral syrup. Follow your doctor's instructions for the use of this medication.

There is not an Isoniazid manufacturer coupon or patient assistance program currently available, but you can save on your prescription cost by using our free Isoniazid coupon card. Our customers typically find that they save more by using our coupons instead of manufacturer coupons.