Clinically important drug interactions with intravenous anaesthetics in older patients.

There is a continuously growing population of older surgical patients who require an increasing number of anaesthetics and sedation. Pharmacokinetic and pharmacodynamic changes associated with increasing age are often not appreciated enough. Dose requirements for midazolam, a benzodiazepine commonly used for outpatient procedures, have been demonstrated in prospective studies to decrease with increasing age. On the other hand, rigorous prospective studies investigating the effect of age on the induction doses of other intravenous anaesthetics, such as thiopental sodium or propofol, are missing. In addition, many of those patients take multiple drugs for medical problems often not related to the procedure. Drug interactions with anaesthetics are likely to occur, but are not well documented. In this review we have summarised the documented and clinically relevant drug interactions with anaesthetics in the elderly population. We have identified a significant lack of scientific and outcome data and the need for more studies and education.