阴茎不能获得和(或)维持充分的勃起以完成满意性交的病理状态称之为勃起功能障碍(erectile dysfunction,ED)。ED是一个广泛存在的健康问题,世界范围内的发病率约为10%~20%,其对病人及其伴侣的生活质量都带来了极大的困扰。1998年,磷酸二酯酶5抑制剂(phosphodiesterase type-5 inhibitors,PDE5-i)第一个代表药物西地那非的问世,使ED的治疗取得了突破性的进展。该类药 The erectile dysfunction (erectile dysfunction, ED) is the pathology in which the penis can not acquire and / or maintain adequate erection to achieve satisfactory sexual intercourse. ED is a widespread health problem with a worldwide incidence of about 10% to 20%, which has greatly disturbed the quality of life of patients and their partners. In 1998, the advent of sildenafil, the first representative of phosphodiesterase type-5 inhibitors (PDE5-i), made a breakthrough in the treatment of ED. Such drugs