"Bicycle kickstand" phenomenon: prolonged erections associated with antipsychotic agents.

The purpose of this paper is to draw attention to the ability of some antipsychotic agents to produce sustained erection short of priapism. They appear to have this effect consistently over time in some individuals. The effect is rapidly reversible on discontinuation of the drug, and appears to be dose-dependent. In one of our patients, the "active metabolite" of that same drug could not duplicate the effect. Prevalence and mechanism require clarification. If even a small proportion of patients with the sustained erection phenomenon are found to progress to priapism, this would have profound ramifications. If this phenomenon could be confidently predicted or safely and readily implemented, the benefits for some patients with impotence or premature ejaculation might be considerable. Given all the potential adverse side effects of antipsychotics, it should be appreciated that the potential direct effects on male sexual function are not always adverse.