Isoniazid

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.

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

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.

• 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

• 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

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

• Mild stomach upset.

• 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.

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.