Standard dosage	5 mg/kg up to 300 mg daily in a single dose.
Contraindications	Hypersensitivity to the drug including history of a previous isoniazid-associated hepatic injury.
Major side effects	Peripheral neuropathy, hepatic dysfunction, gastrointestinal symptoms, hematological disturbances, hypersensitivity reactions, and pyridoxine deficiency.
Major drug interactions	May interact with acetaminophen, carbamazepine, ketoconazole, phenytoin, theophylline, and valproate.
Special points	Category C drug in pregnancy.
Cost	Inexpensive.