CAVEATS: Side effects and study funding are worth noting
Side effects. Significantly more participants in the sildenafil group vs the placebo group experienced the following side effects: headache (43% vs 27%), visual disturbance (14% vs 2%), dyspepsia (12% vs 0%), flushing (24% vs 0%), nasal congestion (37% vs 6%), and palpitations (8% vs 2%). Nausea was the only side effect that was more common in the placebo group, reported by only 2% of those in the intervention group but 16% of those on placebo.
No serious adverse events occurred, however, and the medication appears to have been well tolerated overall, despite relatively high rates of side effects. Participants in the intervention group used an average of 5 doses of sildenafil per 2-week interval, the same number as those in the placebo group.
Small treatment effect. The difference in response between sildenafil and placebo was not large: 0.8 points on a 7-point scale. But this difference is likely a clinically meaningful effect to the women with this problem.
Drug company funding. Pfizer, the maker of Viagra, funded this study through an investigator-initiated grant. Some researchers argue that female sexual dysfunction has been defined, or even invented, by drug companies seeking to create new markets for their products.16 This concern, coupled with the fact that this is the only double-blind randomized trial to show that sildenafil benefits women with antidepressant-associated sexual impairment, raises the question of whether this finding will be replicated in future trials.
We were reassured by the authors’ statement that Pfizer had no role in the study design, implementation, analysis, or manuscript preparation. And we know from clinical practice that women do suffer from SRI-induced sexual side effects, and sometimes stop taking much-needed antidepressants because the medication interferes with their ability to have a satisfying sex life. We believe this study was well done and offers a promising new therapy that deserves consideration. We hope that additional trials will follow and that investigators and journals will not hesitate to publish negative results.
Not for all women with sexual dysfunction
It’s a safe bet that these findings will be used to market sildenafil to women. It is therefore important for physicians and patients to keep in mind that this trial focused on a well-defined subset of women with sexual dysfunction: those on a stable dose of an SRI, with depression in remission, who were otherwise healthy and not pregnant, breastfeeding, or planning pregnancy, and who were motivated to be sexually active. Although this study does support the use of sildenafil for women in this subset, it does not support the use of PDE-5 inhibitors such as sildenafil for all women with sexual difficulties.
CHALLENGES TO IMPLEMENTATION: You have to ask!
Studies have repeatedly found that many women who experience sexual problems do not broach the subject with their doctors.17 So don’t wait for your female patients to bring it up. Sexual side effects are common enough with SRI antidepressants that all prescribers should mention the possibility in advance. Tell patients to let you know if they develop medication-related sexual dysfunction, and reassure them that there are treatments that can help.
Acknowledgment
The PURLs Surveillance System is supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.
This study was selected and evaluated using FPIN’s Priority Updates from the Research Literature (PURL) Surveillance System methodology. The criteria and findings leading to the selection of this study as a PURL can be accessed at www.jfponline.com/purls.
