Risks associated with peri-operative use of alpha2-adrenoceptor agonists

Experimentally, α2-agonists keep intact the reactivity of the circulatory system to hypotension or hypovolaemia. These findings have been reproduced in humans outside the anaesthesia/critical care setting. Within the anaesthesia/critical care setting, no studies directly tackle the problem of circulatory reactivity to hypotension. Poor circulatory tolerance (hypotension, bradycardia and low cardiac output) to systemic α2-agonists has been reported in the anaesthetic setting. In contrast, however, most reports in the literature suggest good tolerance. This discrepancy may be a function of the intravascular volume status, the dosage of the anaesthetic/sedative agents co-administered or the specific opiate used. The opinion of the authors is that (a) the administration of α2-agonists should be restricted to hypertensive/coronary patients or patients presenting to or recovering from minor or major surgery in whom a high benefit-to-risk ratio is expected, (b) appropriate volume loading before the induction of anaesthesia or intra-hospital transport should be considered, and (c) a reduction in anaesthetic/sedative and vasopressor requirements should be considered. Key studies are lacking