The mechanism of erectile dysfunction associated with psychotherapeutic medication is nt well defined. To determine whether psychotherapeutic drugs have a direct effect on penile cavernosal smooth muscle, the activity of 4 drugs from 4 major
classes of
psychotherapeutic agents, chlorpromazine, thioridazine, haloperidol and amitriptyline, was examined in vitro on isolated rabit corpus cavernosum. Strips of corpus cavernosum were mounted in organ baths for isometric tension studies. The effect of
the
drugs on resting tension, their relaxant effect on norepinephrine (NE0 precontracted tissue, and their effect on electrical field stimulated (EFS) relaxation of NE precontracted tissue were determined. Incubation with any of the drugs did not
affect
resting tension compared to a control. All drugs produced a dose-dependent relaxation in NE precontracted tissue which were significanlty greater than the water treated control (p<0.0001). None of the drugs inhibited EFS relaxation. These result
show
that these clssses of durgs do not affect the basal tone of the corpus cavernosum. All have intrinsic relaxant properties and none interfere with neurally stimulated relaxation. This study suggests tjat drugs from these 4 major classes of
psychotherapeutic agents do not adversely affect penile cavernosal smooth muscle relaxation at the level of the penis and its associated neural elements. It may be inferred that reports of impotence in patients treated with these classes of drugs
more
likely reflect a central or primary psychopathologic process rather than a local corpus cavernosum effect.
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