The effect of age on the relative potency of midazolam and diazepam for sedation in upper gastrointestinal endoscopy.

Diazepam and midazolam are considered safe and effective sedative agents for diagnostic procedures. However, there have been recent reports of deaths in older patients receiving midazolam for sedation. We examined the relative potency of diazepam compared with midazolam as a function of age in two large groups of patients receiving intravenous benzodiazepines for upper gastrointestinal endoscopy. While midazolam and diazepam are approximately equivalent before age 60, after age 60 the relative potency of midazolam compared with diazepam increases markedly. The rapid decline in dose necessary to sedate older patients with midazolam may explain deaths occurring in older patients who have received this drug. Until this problem receives definitive study, we advise that diazepam be preferred over midazolam for intravenous sedation in patients over 60.