The influence of age on the onset of anaesthesia with midazolam.

There was a considerable individual variation in response to a standard induction dose of 0.3 mg/kg midazolam in unpremedicated patients. This is shown by variations in time to onset of sleep and the fact that about one quarter of subjects did not lose consciousness in 3 minutes. In 166 fit patients a good negative correlation was demonstrated between the age of the patients and time to loss of consciousness. Patients over 50 years differed from younger patients in a greater reliability of effect and significantly shorter induction time. In elderly patients midazolam is a more reliable induction agent than in the young.