dexmedetomidin

Dexmedetomidine is a sedative and analgesic agent used in anesthesia and critical care. It is a highly selective alpha-2 adrenergic receptor agonist, acting mainly in the locus coeruleus and spinal cord to produce sedation and anxiolysis with analgesic-sparing effects. Unlike many sedatives, it tends to preserve spontaneous respiration at customary doses.

Medical uses include short-term sedation of adults in intensive care units, particularly for mechanically ventilated patients, and as an adjuvant during general anesthesia to provide intraoperative and postoperative sedation. It is also used for procedural sedation in adults and, with varying experience, in pediatric patients. By reducing opioid requirements, it may contribute to smoother recovery in some settings.

Administration and dosing are by intravenous infusion. Some regimens use a loading dose (for example about 1 mcg/kg over 10 minutes) but this can provoke hypotension and bradycardia, so many guidelines recommend starting without a loading dose. Maintenance infusion typically ranges from about 0.2 to 0.7 mcg/kg per hour, titrated to the desired level of sedation and usually limited to the duration of the procedure or ICU stay. Dexmedetomidine is metabolized in the liver and excreted as metabolites.

Pharmacokinetics: it is highly selective for alpha-2 receptors, with a rapid distribution phase and an elimination half-life of about 2 hours; the context-sensitive half-life increases with longer infusions.

Adverse effects and safety: the most common are bradycardia and hypotension; dry mouth and nausea may occur, and respiratory depression is uncommon but possible at high doses or with other depressants. Caution is warranted in patients with significant bradyarrhythmias, advanced heart block, severe hypotension, or hepatic impairment, and when combined with other agents that lower heart rate or blood pressure. Dexmedetomidine is approved in many markets under the brand name Precedex.