α-ADRENERGIC AGONISTS: DEXMEDETOMIDINE
History
Adrenergic receptors were first differentiated into α and
β by Ahlquist based on their responses to various amines.[659]
α2
-Adrenergic agonists provide sedation, anxiolysis, and hypnosis,
as well as analgesia and sympatholysis. The initial impetus for the use of α2
-agonists
in anesthesia resulted from observations made in patients during anesthesia who were
receiving clonidine therapy.[659]
[660]
[661]
This was soon followed by a description of
the MAC reduction of halothane by clonidine.[662]
Dexmedetomidine is a far more selective α2
-agonist, with 1600-fold
greater selectivity
Figure 10-25
Chemical structure of dexmedetomidine.
for the α2
- than the α1
-receptor. It has recently
been approved for brief sedation (<24 hours).
