Anticholinergic side-effects of antidepressants: studies of the inhibition of salivation.

Studies of the peripheral anticholinergic effects of antidepressants initiated by Ole J. Rafaelsen are reviewed. They were all cross-over trials, either in patients who received continuous medication or in which continuous medication was temporarily discontinued, or in volunteers given single doses. Anticholinergic effects were evaluated from the inhibition of salivation rate measured by a tampon method. In essence, the studies revealed that 1) the method was sufficiently reliable and sensitive, 2) inhibition of salivation by tricyclic antidepressants persisted during long-term treatment, and 3) the newer antidepressants Nomifensine, Zimeldine, Mianserin, Citalopram, and Femoxetine were less potent as to anticholinergic effects than tricyclic antidepressants. The results of the studies reviewed have generally been in good agreement with similar studies of other centers and with clinical between-group studies. Other authors have found a sufficient specificity of salivation rate measurements for anticholinergic effects, but other methods, for instance based on heart rate measurements, may prove to be more specific.