Aripiprazole-induced priapism

Priapism is a urologic emergency representing a true disorder of penile erection that persists beyond or is unrelated to sexual interest or stimulation. A variety of psychotropic drugs are known to produce priapism, albeit rarely, through their antagonistic action on alpha-1 adrenergic receptors. We report such a case of priapism induced by a single oral dose of 10 mg aripiprazole, a drug with the least affinity to adrenergic receptors among all atypical antipsychotics. Polymorphism of alpha-2A adrenergic receptor gene in schizophrenia patients is known to be associated with sialorrhea while on clozapine treatment. Probably, similar polymorphism of alpha-1 adrenergic receptor gene could contribute to its altered sensitivity and resultant priapism. In future, pharmacogenomics-based approach may help in personalizing the treatment and effectively prevent the emergence of such side effects.