ViagraThe US Food and Drug Administration (FDA) has approved Addyi (flibanserin) for the treatment of acquired generalised hypoactive sexual desire disorder (HSDD) in premenopausal women.

The approval means flibanserin is the first drug to be FDA-approved for the treatment of sexual desire disorders in men or women.

HSDD is characterised by low sexual desire that causes marked distress or interpersonal difficulty and is not due to a co-existing medical or psychiatric condition, problems within the relationship or the effects of a medication or other drug substance. HSDD is acquired when it develops in a patient who previously had no problems with sexual desire. HSDD is generalised when it occurs regardless of the type of sexual activity, the situation or the sexual partner.

However, the approval came with a number of warnings. Flibanserin can cause severely low blood pressure (hypotension) and loss of consciousness (syncope). These risks are increased and more severe when patients drink alcohol or take flibanserin with medicines that interfere with the breakdown of Addyi in the body (known as moderate or strong CYP3A4 inhibitors). Due to the alcohol interaction, the use of alcohol is contraindicated while taking flibanserin. Healthcare professionals must assess the likelihood of the patient reliably abstaining from alcohol before prescribing flibanserin.

 “[This] approval provides women distressed by their low sexual desire with an approved treatment option,” said Janet Woodcock, MD, director of the FDA’s Center for Drug Evaluation and Research (CDER). “The FDA strives to protect and advance the health of women, and we are committed to supporting the development of safe and effective treatments for female sexual dysfunction.

“Because of a potentially serious interaction with alcohol, treatment with Addyi will only be available through certified health care professionals and certified pharmacies. Patients and prescribers should fully understand the risks associated with the use of Addyi before considering treatment.”

The effectiveness of the 100mg bedtime dose of flibanserin was evaluated in three 24-week randomised, double-blind, placebo-controlled trials in about 2,400 premenopausal women with acquired, generalised HSDD. The average age of the trial participants was 36 years, with an average duration of HSDD of about 5 years.

In these trials, women counted the number of satisfying sexual events, reported sexual desire over the preceding four weeks (scored on a range of 1.2 to 6.0) and reported distress related to low sexual desire (on a range of 0 to 4). On average, treatment with flibanserin increased the number of satisfying sexual events by 0.5 to one additional event per month over placebo, increased the sexual desire score by 0.3 to 0.4 over placebo, and decreased the distress score related to sexual desire by 0.3 to 0.4 over placebo.

Additional analyses explored whether the improvements with flibanserin were meaningful to patients, taking into account the effects of treatment seen among those patients who reported feeling much improved or very much improved overall. Across the three trials, about 10% more flibanserin-treated patients than placebo-treated patients reported meaningful improvements in satisfying sexual events, sexual desire or distress. Flibanserin has not been shown to enhance sexual performance.

The 100mg bedtime dose of Addyi has been administered to about 3,000 generally healthy premenopausal women with acquired, generalised HSDD in clinical trials, of whom about 1,700 received treatment for at least 6 months and 850 received treatment for at least 1 year.