Sun14November1246PM 14

Are the following true or false concerning dexmedetomidine?

True / False

When used as sedation on critical care, is more likely to cause delirium than midazolam Correct

Reduces heart rate and blood pressure in a dose-response fashion Correct

Has a high oral bioavailability Incorrect answer selected

May be used as a sole agent for total intravenous anaesthesia Correct

Acts as an agonist at alpha-2 adrenoreceptors Correct

Explanation

In 2011 dexmedetomidine gained marketing approval in the UK. It is already widely used in the US for sedation, both procedurally and in critical care.

It is a centrally acting selective alpha-2 adrenoreceptor agonist, acting on receptors in the brainstem (locus caeruleus) and the spinal cord.

It has been shown to reduce the incidence of delirium when compared with benzodiazepines.

It causes sedation but is not licensed in the U.K. for use as a sole anaesthetic agent. It has been used as an alternative to remifentanil when used as part of a TIVA technique with propofol.

It is completely cleared by first pass hepatic metabolism and is only available as an IV infusion. Blood pressure and heart rate will fall in a dose-response fashion.

It is a negative chronotrope and acts to reduce peripheral sympathetic tone.

A large randomised control trial published in the Journal of the American Medical Association (JAMA) showed a shorter time to extubation and less delirium than midazolam1.

Reference:

Riker RR, Shehabi Y, Bokesch PM, et al. Dexmedetomidine vs midazolam for sedation of critically ill patients: a randomized trial. JAMA. 2009;301:489-99.

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Times answered: 247