A Case of Dose-Dependent Lamotrigine-Induced Priapism in a Patient with Bipolar Disorder

Priapism is defined as a prolonged and persistent erection of the penis without sexual stimulation. Priapism can be caused either by organic factors or as a side effect of drugs. Mood stabilizer induced priapism has been reported less frequently compared to other psychotropic agents. This paper reports a case of lamotrigine induced priapism.

A 24-year-old patient had a diagnosis of bipolar disorder for 4 years. He had been treated with lamotrigine (200 mg/day), sertraline (25 mg/day) and risperidone (2 mg/day) for last year. He developed priapism one week after the lamotrigine dose was increased to 300 mg/day during a depressive episode. Priapism improved the day after the lamotrigine dose was reduced to 250 mg/day.

Epilepsy patients with lamotrigine-induced sexual dysfunction or priapism have been reported previously. In this case, a patient diagnosed with bipolar disorder developed dose dependent lamotrigine-induced priapism. In clinical practice, the possible risk of priapism should be taken into consideration in patients using lamotrigine, especially during dose increases.