Effect of clonidine and yohimbine on sleep in healthy men: a double-blind, randomized, controlled trial.

Abstract

To study the acute effect of clonidine, an alpha 2-adrenoceptor agonist, and yohimbine, an alpha 2-adrenoceptor antagonist, on nocturnal sleep in healthy men. McGuire Veteran Affairs Medical Center, Richmond, Virginia, USA. Eight healthy male volunteers. Each subject slept in the sleep laboratory for 2 consecutive nights on three separate sessions, at 3-week intervals. On the 2nd night of each session, the subjects received yohimbine (5.4 mg), clonidine (0.1 mg), or placebo in a double-blind, randomized, placebo-controlled, crossover design. There were no apparent effects of yohimbine. In contrast, clonidine completely suppressed rapid eye movement (REM) sleep in one subject and reduced REM sleep in the remaining seven subjects. Our study confirms that clonidine markedly decreases REM, even at a low single dose, and supports the hypothesis of the important role of alpha 2-receptors in controlling REM sleep.