Pharmacology of sedation agents and reversal agents.

Sedation for gastrointestinal endoscopies is obtained by opioids, benzodiazepines, propofol, ketamine and/or droperidol. The pharmacokinetic profile of some sedatives/anesthetics renders them advantageous over others. Opioids, mainly pethidine and fentanyl, are the most popular. Though newer opioids provide a faster recovery, fentanyl is safe and advantageous due to its lower cost. Remifentanil, due to its pharmacokinetic profile (elimination half-life: 9 min), is advantageous for ambulatory patients, though it is not known whether the high cost compensates the benefits. Midazolam is the benzodiazepine of choice as it has a shorter duration of action and a better pharmacokinetic profile than diazepam. Propofol, an intravenous anesthetic, has become very popular for gastrointestinal endoscopies in sedative doses. The opioid and benzodiazepine antagonists, naloxone and flumazenil, are indicated only in particular circumstances, like deep sedation with threatening respiratory depression. Ketamine and droperidol are not popular agents for sedation in the modern endoscopic practice.