This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti Microbial, Subject name: Pharmacology
All the following anti-tubercular drugs are hepatotoxic except 
Select and explain. 
A. Rifampicin, B. INH, C. Ethambutol, D. Pyrazinamide
C: Ethambutol
Answer: C: Ethambutol 
Explanation: Ans. c (Ethambutol). (Ref. Harrison's Medicine - 18th/Table 168-3; KD Tripathi 5th/- 703)# Hepatotoxic AKT drugs- INH- Rifampicin- Pyrazinamide (most toxic)# Nephrotoxic AKT drug- Streptomycin# Neurotoxic drugs- Cyclosporin- INH# Drug Contraindicated in AIDS- ThiacetazoneOptic neuritis, the most serious adverse effect of ethambutol.