Pharmacokinetics and Pharmacodynamics of Oral Transmucosal Dexmedetomidine.

The alpha2-adrenoceptor agonist, dexmedetomidine, was originally developed as a sedative and analgesic drug for use in intensive care. However, it has a number of unique pharmacodynamic properties, which also make it useful in anesthesia including; decreased MAC, analgesia without respiratory depression and a significant reduction in catecholamine secretion. Also it has been used off-label as an adjunctive agent for sedation and analgesia in patients in the critical care unit and for sedation during non-invasive procedures in radiology. It also has a potential role as part of anesthesia care to prevent emergence delirium and post-anesthesia shivering.

Oral trans-mucosal administration is relatively easy and convenient, it also reduces first pass metabolism and has been used successfully for fentanyl, ketamine, and midazolam premedication.

The current literature is focused in studying the sedative and analgesic effects of intravenously administered dexmedetomidine. Pharmacodynamics and pharmacokinetic studies undertaken on alternative routes of dexmedetomidine administration are lacking. The pharmacokinetic properties of trans-mucosal administration of dexmedetomidine have been demonstrated in one study only, and the clinical effects of non-parenteral administration of dexmedetomidine have been described in anecdotal case reports.

Inclusion criteria

• ASA physical status I - II.
• Aged between 20 and 60 years.
• Scheduled for modified radical mastectomy

Exclusion criteria

• Cardiac disease.
• Hepatic disease.
• Renal disease.
• History of alcohol or drug abuse.
• Patients with a known allergy to the study drug