• Tuberculosis (pulmonary and extrapulmonary)
  • Part of modified regimens when Rifampicin is contraindicated
  • Often used in continuation phase in rifampicin-intolerant patients

Typical Adult Dosage (weight-based):

  • 30–37 kg:2 tablet
  • 38–54 kg:3 tablets
  • 55–70 kg:4 tablets
  • >70 kg:5 tablets

Given once daily, usually for 6–9 months, depending on the regimen

  • Ethambutol: 275 mg
  • Isoniazid: 75 mg

(Other formulations may vary depending on country and availability.)

  • Take on an empty stomach or with food if GI upset occurs

  • Take at the same time each day

  • Pyridoxine (Vitamin B6) is recommended with isoniazid to prevent neuropathy

  • Monitor vision regularly due to ethambutol risk

  • Ethambutol: Bacteriostatic; inhibits arabinosyl transferase → interferes with mycobacterial cell wall synthesis

  • Isoniazid: Bactericidal; inhibits mycolic acid synthesis, critical for the cell wall of Mycobacterium tuberculosis

  • GI upset, nausea, fatigue

  • Peripheral neuropathy (isoniazid)

  • Visual disturbances: blurred vision, red-green color blindness (ethambutol)

  • Optic neuritis or known visual impairment

  • Hepatic disease or acute liver injury

  • Hypersensitivity to ethambutol or isoniazid

  • Isoniazid:

    • ↑ levels of phenytoin, carbamazepine, valproate

    • ↑ hepatotoxicity with alcohol, rifampicin, or pyrazinamide

                                   Drug Status

Availability
Pregnancy
Breastfeeding
Schedule
BRAND NAME STRENGTH FORMULATION PACK SIZE MANUFACTURER DISTRIBUTOR
Ethizide 400mg/150mg Tablet 100’s Cosmos Ltd Cosmos Ltd