Abstract
Doxepin caused a fall in blood pressure accompanied by an increase of peripheral blood flow in dogs. Doxepin potentiated the effect of norepinephrine (NE) on blood pressure and nictitating membrane of cats but reduced the effect of epinephrine (E). The pharmacological properties of doxepin resemble those of amitriptyline but differ from imipramine which exhibits a dual effect on blood pressure and a potentiating effect to both NE and E. Doxepin, however, showed less pronounced anticholinergic effects than amitriptyline in the following experiments; spasmolytic action on acetylcholine induced contraction in isolated guinea pig ileum, mydriatic action in mice and protective action against methacholine death in mice. These results suggest that in clinical use, doxepin causes less anticholinergic side effects than amitriptyline.
