Commentary: pharmacological agents for erectile dysfunction and the human sexual response cycle.

Public interest following the approval of sildenafil (Viagra), for the treatment of erectile dysfunction (ED), provides sex therapists with an unprecedented opportunity to educate both lay and professional audiences about the importance of psychosocial factors in the evaluation and treatment of sexual dysfunction. My commentary here briefly summarizes how all four phases of the Human Sexual Response (HSR) cycle are affected by sildenafil.