Effects of dexmedetomidine, a selective α2-adrenoceptor agonist, on hemodynamic control mechanisms

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Abstract
Dexmedetomidine, a selective α2‐adrenoceptor agonist, was administered to five healthy male volunteers in single intravenous doses of 12.5, 25, 50, and 75 µg as part of a placebo‐controlled study. The drug caused dose‐dependent decreases in systolic and diastolic blood pressure. A small initial hypertensive response was observed after injection of the two highest doses. Heart rate was decreased. The concentration of norepinephrine in plasma was decreased significantly (by up to 92%), and the decrease was dose‐dependent. No significant drug‐induced alterations were observed in plasma renin activity or in the concentrations of atrial natriuretic peptide and arginine vasopressin in plasma. Other drug effects included dose‐dependent impairment of vigilance and stimulation of growth hormone secretion. Plasma Cortisol levels were unaffected. Dexmedetomidine is a potentially useful tool for studies of the physiology and pharmacology of α2‐adrenoceptors in human beings and may have therapeutic applications in clinical conditions in which sedative and sympatholytic effects are considered beneficial, such as premedication for anesthesia and surgery. Clinical Pharmacology and Therapeutics (1989) 46, 33–42; doi:10.1038/clpt.1989.103