pyridine-4-carbohydrazide

Absorption
T max is 1 to 2 h.

Distribution
Diffuses readily into cerebrospinal, pleural, and ascitic fluids, tissues, organs, saliva, sputum, feces, placental barrier, and in breast milk.

Metabolism
Primarily by acetylation and dehydrazination.

Elimination
50% to 70% excreted in the urine in 24 h.

Aluminum salts
May reduce oral absorption of isoniazid; give isoniazid 1 to 3 h before aluminum salts.

Carbamazepine
May result in carbamazepine toxicity or isoniazid hepatotoxicity. Monitor carbamazepine concentrations and liver function.

Disulfiram
May result in increased incidence of CNS effects (eg, coordination difficulties, confusion, irritability, aggressiveness).

Enflurane
May result in high-output renal failure in rapid acetylators. Monitor renal function.

Hydantoins
May increase serum hydantoin levels.

Rifampin
May result in higher rate of hepatotoxicity.