The Number Needed to Harm (NNH) for a drug causing liver toxicity is 200. This means:
- A On average, one additional case of liver toxicity occurs for every 200 patients treated ✓
- B 200 patients must be treated to prevent one case of liver toxicity
- C The drug causes liver toxicity in 1 out of every 200 doses administered
- D 200 patients need to be followed to observe one case of drug withdrawal
Correct answer: A. On average, one additional case of liver toxicity occurs for every 200 patients treated
Explanation
NNH = 1/Attributable Risk Increase. An NNH of 200 means that for every 200 patients treated with the drug (compared to control), one additional patient will experience the harm (liver toxicity). A higher NNH indicates a safer drug. NNT (Number Needed to Treat) is the reciprocal of absolute risk reduction and refers to benefit. These metrics are essential for clinical decision-making and communication of drug safety.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.