OFF-LABEL DRUG USE Off-label drug use means a drug that’s approved by the FDA for one purpose is used for a different purpose that hasn’t yet been approved. However, a doctor can still use the drug for that purpose. This is because the FDA regulates the testing and approval of drugs, but not how doctors use drugs to treat their patients. So, your doctor can prescribe a drug however they think is best for your care.

Viagra for Women: How Does It Work, and Is It Safe?

Flibanserin (Addyi), a Viagra-like drug, was approved by the Food and Drug Administration (FDA) in 2015 for the treatment of female sexual interest/arousal disorder (FSIAD) in premenopausal women.

FSIAD is also known as hypoactive sexual desire disorder (HSDD).

Currently, Addyi is only available through certain prescribers and pharmacies. It’s prescribed by approved providers in agreement between the manufacturer and the FDA. A prescriber must be certified by the manufacturer to meet certain FDA requirements.

It’s taken once per day, at bedtime.

Addyi was the first HSDD drug to receive FDA approval. In June 2019, bremelanotide (Vyleesi) became the second. Addyi is a daily pill, while Vyleesi is a self-administered injectable that’s used as needed.

The FDA hasn’t approved Viagra (sildenafil) itself for women to use. However, it has been prescribed off-label for women with a low sex drive.

OFF-LABEL DRUG USE

Off-label drug use means a drug that’s approved by the FDA for one purpose is used for a different purpose that hasn’t yet been approved. However, a doctor can still use the drug for that purpose. This is because the FDA regulates the testing and approval of drugs, but not how doctors use drugs to treat their patients. So, your doctor can prescribe a drug however they think is best for your care.

Evidence of its effectiveness is mixed at best. A review of trials of Viagra in women speculates that positive results are observed in regard to physical arousal. However, this isn’t the case for the more complex nature of FSIAD.

For example, the review detailed a study that gave Viagra to 202 postmenopausal women with primary FSIAD.

Researchers observed an increased amount of arousal sensations, vaginal lubrication, and orgasm in study participants. However, women with secondary FSIAD-associated disorders (such as multiple sclerosis (MS) and diabetes) reported no increase in desire or enjoyment.

A second study discussed in the review found that both premenopausal and postmenopausal women reported no significant positive responses when using Viagra.

There are several reasons that women would seek out a Viagra-like pill. As they approach middle age and beyond, it’s not uncommon for women to observe a decrease in their overall sex drive.

A decrease in sex drive can also originate from daily stressors, significant life events, or chronic conditions such as MS or diabetes.

However, some women observe a decrease or absence in sex drive due to FSIAD. According to one expert panel and review, FSIAD is estimated to affect about 10 percent of adult women.

It’s characterized by the following symptoms:

• limited or absent sexual thoughts or fantasies
• loss of interest or inability to maintain interest in sexual activities
• significant feelings of frustration, incompetence, or worry at the lack of sexual interest or arousal

Flibanserin was originally developed as an antidepressant, but it was approved by the FDA for treatment of FSIAD in 2015.

Its mode of action as far as it relates to FSIAD isn’t well-understood. It’s known that taking flibanserin regularly raises levels of dopamine and norepinephrine in the body. At the same time, it lowers levels of serotonin.

Both dopamine and norepinephrine are important for sexual excitement. Dopamine has a role in boosting sexual desire. Norepinephrine has a role in promoting sexual arousal.

The FDA approval of flibanserin was based off the results of three phase III clinical trials. Each trial lasted 24 weeks and evaluated the efficacy of flibanserin compared to a placebo in premenopausal women.

The investigators and the FDA analyzed the results of the three trials. When adjusted for placebo response, about 10 percent of participants reported a “much improved” or “very much improved” status in trial weeks 8 to 24. This is a modest improvement when compared to Viagra.

A review published three years after Viagra’s FDA approval for treating erectile dysfunction (ED) summarizes the worldwide responses to treatment. In the United States, for example, 74 percent of participants responded positively. This is compared to a 19 percent positive response for those taking a placebo.

In postmenopausal women

Flibanserin isn’t FDA-approved for use in postmenopausal women. However, the efficacy of flibanserin in this population was assessed in a single trial.

The results were reported as similar to those reported in premenopausal women. This will need to be replicated in additional trials for it to be approved for postmenopausal women.