Drug Name

Isoniazid

Drug Uses

Isoniazid is used for treating or preventing tuberculosis (TB). If you are using Isoniazid to treat TB, it should always be used along with another medicine.

How Taken

Use Isoniazid as directed by your doctor. Check the label on the medicine for exact dosing instructions.

Isoniazid is usually given as an injection at your doctor's office, hospital, or clinic.

Do not use Isoniazid if it contains particles, is cloudy or discolored, or if the vial is cracked or damaged.

Keep this product, as well as syringes and needles, out of the reach of children and pets. Do not reuse needles, syringes, or other materials. Ask your health care provider how to dispose of these materials after use. Follow all local rules for disposal.

Continue to use Isoniazid even if you feel well. Do not miss any doses.

Drug Class and Mechanism

Isoniazid is an antibacterial. It works by killing TB organisms.

Missed Dose

If you miss a dose of Isoniazid , use it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not use 2 doses at once.

Storage

Store Isoniazid between 68 and 77 degrees F (20 and 25 degrees C). Brief storage at temperatures between 59 and 86 degrees F (15 and 30 degrees C) is permitted. Store away from heat, moisture, and light. Do not store in the bathroom. Keep Isoniazid out of the reach of children and away from pets.

Warnings/Precautions

Do not use Isoniazid if:

• you are allergic to any ingredient in Isoniazid or have had severe side effects from Isoniazid, such as drug fever, chills, or arthritis;
• you have severe liver damage, active liver disease, or liver disease from previous use of Isoniazid.

Contact your doctor or health care provider right away if any of these apply to you.

Some medical conditions may interact with Isoniazid . Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have diabetes, kidney problems, nerve problems (eg, neuropathy) or risk of nerve problems, HIV, or a history of liver problems
• if you have a history of alcohol or other substance abuse, have unsanitary injectable drug habits, or drink alcohol daily
• if you are older than 35 years old, you have recently given birth, or you have previously taken Isoniazid

Some MEDICINES MAY INTERACT with Isoniazid . Tell your health care provider if you are taking any other medicines, especially any of the following:

• Acetaminophen, anticoagulants (eg, warfarin), carbamazepine, hydantoins (eg, phenytoin), rifampin, theophylline, or valproic acid because the risk of their side effects may be increased by Isoniazid
• Ketoconazole because its effectiveness may be decreased by Isoniazid

Possible Side Effects

Check with your doctor if any of these most common side effects persist or become bothersome:

• Mild stomach upset.

Seek medical attention right away if any of these severe side effects occur:

• Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); bloody stools; changes in vision; chills or fever; dark urine; general feeling of discomfort; joint pain or swelling; loss of appetite; memory problems; mental or mood changes; nausea; seizures; severe diarrhea; stomach pain; tingling or numbness in the hands or feet; unusual bruising or bleeding; unusual tiredness or weakness; vomiting; yellowing of the skin or eyes.

More Information

If you have any questions about Isoniazid , please talk with your doctor, pharmacist, or other health care provider.

Isoniazid is to be used only by the patient for whom it is prescribed. Do not share it with other people.

If your symptoms do not improve or if they become worse, check with your doctor.