Frequent Episodic Vertigo is an Unexpected Side Effect of Flutamide

An 82-year-old male suffered from prostatic cancer five years ago. Since then, he has taken flutamide and was bothered with episodic vertigo (EV) every morning. In order to treat prostatic cancer, flutamide was not discontinued, but conservative treatment and life-style change were recommended. Finally, EV actually subsided. Herein, we report the rare case, in which EV was an unexpected side effect of flutamide. Herein we review his whole history, physical examination, vestibular function test, electronystagmogram, caloric test, awake encephalogram, blood examinations, color-coded duplex ultrasonogram and magnetic resonance imaging/angiogram to suggest a mechanism of flutamide responsible for EV.