Antimicrobials
Isoniazid

Isoniazid

None
Excellent

Dosing

General Information

  • Active Tuberculosis
  • Latent Tuberculosis

Contraindicated in patients with acute liver disease or previous isoniazid-associated hepatic injury.

Laboratory

  • LFTs in patients with underlying liver disease or comorbidities
  • For ALT or AST >3 times the ULN: discontinue or temporarily withhold treatment

Clinical

  • Monitor for signs of hepatic dysfunction

>10%:

  • Hepatic: Increased serum transaminases (mild and transient 10% to 20%)
  • Multiple CYP Interactions
  • Review with clinical pharmacist on call for any doubt of drug drug interaction

Food reduces the rate and extent of absorption, Isoniazid should be taken at least 1hr before or 2hrs after meal.

Absorption readily absorbed 

Distribution widely distributed in all fluids and tissue, pleural and ascitic fluid 

Therapeutic level is attained in CSF 

Pregnancy category C 

Breastfeeding compatible

Adapted from the UCLA Health Antimicrobial Stewardship Program