Viagra (sildenafil) is approved to treat sexual dysfunction in men by the U.S. Food and Drug Administration (FDA), but it is sometimes prescribed to women off-label, which means without approval by the FDA. Viagra is an effective drug for treating male erectile dysfunction, but it targets sexual performance, not sexual arousal. There is limited evidence that Viagra may be beneficial for women with sexual dysfunction, but the trials have been small and the results inconsistent.
In men, Viagra works by relaxing smooth muscle in the penis. This allows blood to flow into the penis which causes an erection.
In women, Viagra can increase blood flow to the clitoris and the labia of the vagina which may increase lubrication and sensation. This may help some women with sexual arousal and orgasm, especially in women after menopause with vaginal dryness. There have been only a few studies on the use of Viagra in women with sexual dysfunction. The results of these studies have not shown consistent benefits.
Viagra also has side effects, including:
- Headache
- Nasal congestion
- Nausea
- Visual disturbances.
According to the FDA, the safety of Viagra for women during pregnancy or breastfeeding has not been studied in humans. Viagra does pass into breast milk, and it is not known if it has any effects on breastfed babies.
Note that sildenafil, the active ingredient of Viagra, is also available as Revatio, which may be used to treat pulmonary hypertension in both men and women, albeit at a much smaller dose.
FSIAD
The most common sexual disorder in women is called female sexual interest and arousal disorder (FSIAD). Viagra has not proven to be helpful for this condition because FSIAD is more complex than erectile dysfunction in men. FSIAD can be diagnosed if a woman has reduced or lost her interest in sex, has reduced or lost desire, arousal, response or pleasure. These symptoms should be present for at least 6 months and not be caused by relationship problems, medications, substance abuse, stress or another medical condition.
To be considered FSIAD, the sexual dysfunction must be causing a woman a significant amount of distress. Low sexual desire is found in about 20% to 30% of women, but only about half of these women experience significant distress. FSIAD is most common in women who are in a relationship and would like to be more sexually active and responsive. Lack of interest in sex itself is not abnormal, especially in women who do not want to be in a relationship or who have lost interest in sex at older ages.
Addyi
There is one drug that has been approved by the FDA to treat women with low sexual desire. The name of the drug is Addyi (flibanserin). It was approved in 2015 for women before menopause.
It is not known how this drug works. It was developed as an antidepressant. Studies show that Addyi causes a small but significant increase in monthly satisfying sexual events compared to a placebo (about 1 to 2 more events).
It comes with significant side effects, and it must be taken every day. The side effects include:
- Dizziness
- Sleepiness
- Fatigue
- Insomnia
- Dry mouth
- Nausea
The drug is taken at bedtime to avoid these side effects during the day.
The FDA says women should stop taking Addyi if they do not have improvement in sexual desire after 8 weeks.
In 2019, the FDA issued a warning that alcohol must be avoided in women taking Addyi. Addyi taken with alcohol can cause a severe drop in blood pressure, which may cause syncope (passing out). The warning about alcohol and Addyi is a boxed warning. That means the warning must appear in a box at the top of the drug insert. A boxed warning is the highest warning given by the FDA.