Reversible Myopathy and Ophthalmoparesis After Low-Dose Finasteride Administration for Androgenic Alopecia

A 35-year-old man experienced sudden-onset weakness of the bilateral proximal-dominant extremities and associated muscle pain, as well as diplopia, after taking finasteride 1 mg per day for androgenic alopecia for 4 months. He was diagnosed with sub-acute-onset, progressive myopathy and partial ophthalmoparesis. After discontinuing the drug, his symptoms gradually improved and he fully recovered after 1 month. This is the first report of myopathy during use of low-dose (1 mg) finasteride. Physicians should consider 1 mg of finasteride as a possible cause when a patient complains of progressive myalgia or weakness.