Sildenafil and Female Sexual Response
While sildenafil does increase genital blood flow in women, current NCCN guidelines explicitly do not recommend its use for female sexual dysfunction due to contradictory clinical trial results and lack of proven effectiveness on meaningful sexual outcomes. 1
The Evidence on Physical Genital Response
Yes, sildenafil does increase physical genital blood flow in women. Multiple studies demonstrate measurable improvements in clitoral and vaginal blood flow:
- Clitoral blood flow: Sildenafil significantly increases peak systolic velocity and reduces resistance in clitoral arteries within 1 hour of administration 2, 3, 4
- Uterine blood flow: Also improves with reduced resistance and pulsatility indexes 3
- Physiologic measurements: Post-stimulation genital blood flow, vaginal lubrication, and intravaginal pressure-volume changes all improved significantly compared to baseline 5
These physiologic effects are consistent with sildenafil's mechanism as a PDE-5 inhibitor, which increases cGMP in vascular smooth muscle, causing vasodilation 6.
The Problem: Blood Flow ≠ Sexual Function
Here's the critical disconnect: While sildenafil reliably increases genital blood flow, this does not consistently translate into improved sexual arousal or function in women. The NCCN guidelines explicitly state that PDE-5 inhibitors "showed contradictory results in randomized clinical trials of various noncancer populations of women being treated for sexual arousal disorder." 1
Why Guidelines Recommend Against Use
The 2014 NCCN Survivorship Guidelines are clear: "Currently, the panel does not recommend the use of oral phosphodiesterase type 5 inhibitors (PDE5i) for female sexual dysfunction because of the lack of data regarding their effectiveness in women." 1
This recommendation persists despite the drug being "thought to increase pelvic blood flow to the clitoris and vagina" because clinical trials showed inconsistent results on actual sexual function outcomes. 1
What About Subjective Arousal?
Some smaller studies suggest subjective improvements:
- One pilot study showed improvements in arousal, desire, satisfaction, and orgasm after 6 weeks 5
- Another found improvements in arousal, orgasm, and sexual enjoyment in diabetic women 7
However, these are small, uncontrolled studies. The guideline authors reviewed the totality of evidence, including larger randomized controlled trials that showed contradictory results, and concluded the evidence is insufficient to recommend use.
The Bottom Line for Clinical Practice
Sildenafil increases genital blood flow but should not be prescribed for female sexual arousal disorder. The 2016 NCCN guidelines mention PDE5 inhibitors only in the context of male sexual dysfunction, not female 8.
Recommended Alternatives for Women
Instead, evidence-based options include:
- Vaginal lubricants and moisturizers for dryness
- Pelvic floor physical therapy for arousal, lubrication, and orgasm issues
- Vaginal estrogen for postmenopausal symptoms
- Flibanserin for hypoactive sexual desire disorder (though controversial)
- Referral to sexual medicine specialist for persistent concerns 8, 1
Common Pitfall to Avoid
Don't assume that because sildenafil works for male erectile dysfunction (which is primarily a vascular problem), it will work for female sexual arousal disorder. Female sexual response is more complex, involving psychological, hormonal, and relationship factors beyond just genital blood flow. The lack of correlation between increased blood flow and improved sexual function in women demonstrates this complexity.