BACKGROUND: Sildenafil has been proved an effective oral pill for erectile dysfunction in men. Synthesis and releases of nitric oxide may also regulate clitoral corpus cavernousum smooth muscle tone. Thus, the same mechanism that regulates male erections may play a role in female sexual arousal disorder. Sexual arousal disorder is the persistent or recurrent inability to attain or maintain sufficient sexual excitement, expressed as a lack of genital lubrication or swelling response.
POPULATION STUDIED: Study subjects included 53 volunteer women ages 22 to 38 years seen in a sexual arousal disorders clinic in Italy for an inability to attain orgasm. Eligible women were healthy, with a subjectively normal sexual desire, not taking any known medications that could effect sexual arousal, had not experienced any clitoral and vaginal sensation or were slow to respond, and had not lubricated for a minimum of 6 months; they were all in stable, satisfying heterosexual relationships.
STUDY DESIGN AND VALIDITY: Subjects were randomized in a double-blind, 3 crossover periods fashion (allocation assignment concealed) to each of 6 possible sequences, each consisting of 3 medication series: (1) sildenafil 25 mg; (2) sildenafil 50 mg; and (3) placebo. Each participant took either dose of sidenafil or placebo 1 hour before planned intercourse. Each drug was used for a 4-week period, with a 1-week washout period between treatment periods. Patients were followed monthly for a total of 3 months. Since the study subjects were those seen in a tertiary care center they may not reflect similar patients seen by family physicians.
OUTCOMES MEASURED: The authors used a 5-point Likert Personal Experience Questionnaire to detect changes in sexual behavior, measuring scores at baseline and at the conclusion of each 4-week period. No documentation was given regarding reproducibility and internal validity of the findings. The primary outcome measured was arousal score. Secondary outcomes included an ability to achieve an orgasm, sexual enjoyment, frequency of intercourse, and the number of sexual fantasies.
RESULTS: Of the 53 women who initiated treatment, complete follow-up information was available on 51. Sexual arousal scores (sexual enjoyment, feeling of satisfaction, and frequency of sexual fantasies) improved with both doses of sildenafil, compared with placebo: Average score of 4.2 from a maximum of 5 for either dose versus 2.6 for placebo, compared with 1.5 at baseline (P <.001). The frequency of orgasm also improved significantly with both doses of sildenafil compared with placebo: average score of 3.8 for sildenafil and 2.4 for placebo compared with 1.0 at baseline (P <.001). There were no statistically significant differences between the 2 doses of sildenafil in any of the outcomes measured and the order in which the treatments were allocated did not show any effect. Four women (7.8%) stopped taking sildenafil 50 mg, 2 women (3.9%) stopped taking sildenafil 25 mg, and 2 women (3.9%) stopped taking placebo. Reasons given for discontinuing treatment included vision problems, headache and fear of adverse reactions.
This is a small, well-designed study showing a benefit of sildenafil treatment for young women with sexual arousal disorder, including an increased ability to lubricate, achieve orgasm, and experience sexual satisfaction. Women participating in this study had normal sexual desire, which was not altered by sidenafil use. The old-time myth that the sexual response is “all in one’s head” is rapidly being disproved. Consideration should be given in certain circumstances to prescribing sildenafil for both women and men.