Baylor University Medical Center Proceedings January 2014, Volume 27, Number 1 | Page 13

Invited commentary
Role of alpha-2 agonists for postoperative pain relief
cute postoperative pain is a complex and difficult problem to manage in the perioperative period. In addition
to causing patient discomfort, it stimulates the sympathetic nervous system, increases myocardial oxygen
demand, delays mobilization, impairs the immune system, and
may potentially lead to chronic pain. Multimodal analgesia
appears to be a very attractive method for postoperative pain
management, as it decreases opioid requirements and thus associated complications such as nausea, emesis, and respiratory
depression. The use of alpha-2 agonists for multimodal analgesia
in the postoperative period has several potential benefits and is
worth investigating.
Several studies have looked at the risks and benefits associated with the use of dexmedetomidine, an alpha-2 agonist, for
postoperative pain. A recent meta-analysis demonstrated that
postoperative dexmedetomidine administration reduced the
average cumulative morphine equivalents by 6.0 mg at 12 hours
and 14.5 mg at 24 hours, as well as pain scores by 1.4 at 1 hour
and 0.6 at 24 hours. The same study showed that dexmedetomidine was more effective than acetaminophen but less effective
than ketamine or nonsteroidal antiinflammatory medications.
Alpha-2 agonists also seem to decrease postoperative nausea
and vomiting, presumably by reducing the sympathetic tone;
it has been suggested that postoperative nausea and vomiting
may be triggered by high catecholamine concentrations. The
main risk for using dexmedetomidine was the increased risk of
postoperative bradycardia (1, 2). An animal study showed that a
single intraperitoneal dose of dexmedetomidine had a long-term
antinoci