🦠microbiology review

Isoniazid

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Isoniazid is an antibiotic used primarily to treat and prevent tuberculosis. It works by inhibiting the synthesis of mycolic acids, essential components of the bacterial cell wall.

5 Must Know Facts For Your Next Test

  1. Isoniazid specifically targets Mycobacterium tuberculosis.
  2. It is often used in combination with other antibiotics to prevent drug resistance.
  3. The drug can cause side effects like liver toxicity and peripheral neuropathy.
  4. Isoniazid is a prodrug that requires activation by a bacterial enzyme called KatG.
  5. The development of resistance to isoniazid can occur through mutations in the katG gene or alterations in the target site.

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