Intravenous midazolam for upper gastrointestinal endoscopy: a study of 800 consecutive cases relating dose to age and sex of patient

Abstract

In many endoscopy units midazolam is replacing diazepam as the intravenous sedative of first choice. Midazolam is approximately twice as potent as diazepam. Although generally considered a safe drug, there have been a number of recent reports, particularly in the elderly, of the drug causing hypotension, respiratory depression and even death. There have been at least ten studies comparing diazepam with midazolam for upper gastrointestinal endoscopy but many have involved relatively small numbers and none have adequately addressed the question of dosage in the elderly. We have carefully recorded the dose of intravenous midazolam used to produce adequate sedation prior to upper gastrointestinal endoscopy in 800 consecutive patients. The dose of midazolam decreased markedly with age in both male and female patients. There was a highly significant correlation in both sexes between age and the dose of midazolam (rho -0.787, P less than 0.001 for males and rho -0.768, P less than 0.001 for females). There was only a small difference in dose in men and women, an average of 1 mg; and no difference in dose over the age of 70 years. In patients over 70 years of age the dose of midazolam necessary for endoscopy is often so small that overdosage is all too easy.