Isoniazid

Please note: This is for information only.

Refer to local guidelines for treatment recommendations.


  • Antituberculosis agent, used in combination with other antituberculosis agents (exception prophylaxis)
  • Good oral bioavailability
  • Excellent tissue (including brain) and CSF penetration
  • Adjust dose in severe renal impairment
  • Usual combination dose is 2 tablets of Rifinah – 300 once a day (if wt>50kg). (This is a combination agent with rifampicin)
  • Check liver function tests prior to starting therapy. Caution in patients with pre-existing liver disease.

Main indications

  • Mycobacterial disease as part of combination therapy

Active against most strains of:

  • M.tuberculosis
  • Varying activity against atypical mycobacteria

Not active against most strains of:

  • Non-mycobacterial bacteria