US regulators have approved the first 'female Viagra', a drug known as Addyi that works on the brain to boost younger women's libido if they have lost interest in sex.
Made by North Carolina-based Sprout Pharmaceuticals, Addyi, also known as flibanserin, received the nod from the US Food and Drug Administration, on the condition that extra care is taken to ensure women do not take it with alcohol due to the risk of serious side effects.
"Today's approval provides women distressed by their low sexual desire with an approved treatment option," said Janet Woodcock, director of the Food and Drug Administration's Center for Drug Evaluation and Research.
The FDA approved Addyi specifically for a condition known as 'acquired, generalised hypoactive sexual desire disorder (HSDD)', or sudden and severe loss of libido.
"Prior to Addyi's approval, there were no FDA-approved treatments for sexual desire disorders in men or women," the agency said.
The disorder can develop in women who previously were sexually active, causing distress and relationship problems, "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."
The drug must not be taken with alcohol, and will only be available at certified pharmacies because of the potentially serious interaction with alcohol, including risks such as fainting and severely low blood pressure.
"Patients and prescribers should fully understand the risks associated with the use of Addyi before considering treatment," Woodcock added.
In June, an advisory panel to the Food and Drug Administration urged regulators to approve flibanserin, after previously voting against it twice in years past. The FDA is not required to follow the advice of the panel, but it often does.
Attempts to bring the drug to market failed in 2010 and 2013, given what experts described as inconclusive advantages when compared to a placebo.
According to documents on the FDA website, women taking flibanserin reported on average 4.4 sexually satisfying encounters per month, compared to 3.7 in a placebo group and 2.7 before beginning the study.
"It has been a remarkable journey to get to this breakthrough moment. Today, we celebrate what this approval means for all women who have long awaited a medical treatment option for this life impacting condition," said Cindy Whitehead, chief executive officer of Sprout.
"We applaud the FDA for putting the patient voice at the center of the conversation and for focusing on scientific evidence."
The drug is a non-hormonal agent that acts on neurotransmitters in the brain, and aims to treat HSDD among women who have not yet entered menopause. Rebecca Zucconi, an assistant professor of medical sciences at the Frank H. Netter School of Medicine at Quinnipiac University, said the condition is the most commonly diagnosed sexual dysfunction in women.
"Until now, physicians have been limited to recommending education, counseling, psychotherapy and, in some cases, off-label usage of testosterone and estrogen therapy as treatment options for otherwise healthy women with HSDD," Zucconi said.
Addyi can have significant side effects including nausea, dizziness and sleepiness.
Safety concerns include sleepiness, fainting, low blood pressure and the potential for hormonal contraceptives and alcohol use to make side effects worse. Experts also raised questions about the increased risk of breast cancer seen in one of two studies on lab animals.