Number Needed to Harm
NNHDéfinition
The number of patients who need to be treated with a drug for one additional patient to experience a specific adverse effect compared to a control. A higher NNH indicates a safer drug for that particular side effect. Comparing NNT and NNH helps assess the overall benefit-risk ratio.
Exemple
If an NSAID has an NNT of 3 for pain relief and an NNH of 50 for GI bleeding, the benefit-risk ratio is favorable for most patients.