Pharmacology · single question
A patient is on long-term isoniazid (INH) for tuberculosis. What is a recognized long-term side effect of isoniazid therapy?
Show answer and explanation
Correct answer: C. Hepatotoxicity (hepatitis)
- A. INCORRECT. Nephrotoxicity is not a primary concern with isoniazid. It is more associated with aminoglycosides (e.g., streptomycin, gentamicin) used in TB regimens.
- B. INCORRECT. Cardiotoxicity is not a recognized major side effect of isoniazid. Peripheral neuropathy (due to pyridoxine/B6 depletion), hepatotoxicity, and lupus-like syndrome are the main concerns.
- C. CORRECT. Hepatotoxicity (drug-induced hepatitis) is the most significant and potentially fatal long-term side effect of isoniazid. Patients on INH require regular monitoring of liver enzymes (AST, ALT). The risk increases with age, alcohol use, and pre-existing liver disease. Patients should be counseled to report symptoms of jaundice, dark urine, and fatigue.
- D. INCORRECT. Ototoxicity (hearing loss and vestibular damage) is associated with aminoglycosides (e.g., streptomycin, amikacin) used in TB treatment, not with isoniazid.