Pharmacology of commonly used analgesics and sedatives in the ICU: benzodiazepines, propofol, and opioids.

The ideal sedative or analgesic agent should have a rapid onset of activity, a rapid recovery after drug discontinuation, a predictable dose response, a lack of drug accumulation,and no toxicity. Unfortunately, none of the earlier analgesics, the benzodiazepines,or propofol share all of these characteristics. Patients who are critically ill experience numerous physiologic derangements and commonly require high doses and long durations of analgesic and sedative therapy. There is a paucity of well designed clinical trials evaluating the safety and efficacy of earlier sedative and analgesic agents in the ICU. In addition, the ever-changing dynamics of patients who are critically ill makes the use of sedation a continual challenge during the course of each patient’s admission. To optimize care, clinicians should be familiar with the many pharmacokinetic, pharmacodynamic, and pharmacogenetic variables that can affect the safety and efficacy of sedatives and analgesics.