Dexmedetomidine

Dexmedetomidine (Precedex®), a pharmacologically active dextroisomer of medetomidine, is a selective α₂-adrenergic receptor agonist. It is indicated in the US for the sedation of mechanically ventilated adult patients in an intensive care setting and in non-intubated adult patients prior to and/or during surgical and other procedures. This article reviews the pharmacological properties, therapeutic efficacy and tolerability of dexmedetomidine in randomized, double-blind, placebo-controlled, multicentre studies in these indications.

Post-surgical patients in an intensive care setting receiving dexmedetomidine required less rescue sedation with intravenous propofol or intravenous midazolam to achieve and/or maintain optimal sedation during the assisted ventilation period than placebo recipients, according to two randomized, double-blind, multinational studies. Moreover, significantly more dexmedetomidine than placebo recipients acquired and/or maintained optimal sedation without rescue sedation. Sedation with dexmedetomidine was also effective in terms of the total dose of morphine administered, with dexmedetomidine recipients requiring less morphine than placebo recipients; with regard to patient management, dexmedetomidine recipients were calmer and easier to arouse and manage than placebo recipients.

Intravenous dexmedetomidine was effective as a primary sedative in two randomized, double-blind, placebo-controlled, multicentre studies in adult patients undergoing awake fibre-optic intubation or a variety of diagnostic or surgical procedures requiring monitored anaesthesia care. In one study, significantly fewer dexmedetomidine than placebo recipients required rescue sedation with intravenous midazolam to achieve and/or maintain optimal sedation; conversely, in another study, rescue sedation with intravenous midazolam was not required by significantly more dexmedetomidine than placebo recipients. Primary sedation with intravenous dexmedetomidine was also effective in terms of the secondary efficacy endpoints, including the mean total dose of midazolam and fentanyl administered and the percentage of patients requiring further sedation (in addition to dexmedetomidine or placebo and midazolam), with, for the most part, significant between-group differences observed in favour of dexmedetomidine over placebo. In general, no significant differences were observed between the dexmedetomidine and placebo treatment groups in the anaesthesiologists’ assessment of ease of intubation, haemodynamic stability, patient cooperation and/or respiratory stability.

Intravenous dexmedetomidine is generally well tolerated when utilized in mechanically ventilated patients in an intensive care setting and for procedural sedation in non-intubated patients. Dexmedetomidine is associated with a lower rate of postoperative delirium than midazolam or propofol; it is not associated with respiratory depression. While dexmedetomidine is associated with hypotension and bradycardia, both usually resolve without intervention.

Thus, intravenous dexmedetomidine provides a further option as a short-term (<24 hours) primary sedative in mechanically ventilated adult patients in an intensive care setting and in non-intubated adult patients prior to and/or during surgical and other procedures.