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How So-Called ‘Female Viagra’ is Quite Different from Actual Viagra

Before Addyi won FDA approval, there was no prescription drug available for the treatment of decreased sexual desire in women.

Before Addyi won FDA approval, there was no prescription drug available for the treatment of decreased sexual desire in women.

During the lengthy and ultimately successful campaign to win FDA approval for the first prescription drug to treat female sexual function, some headline writers and pundits took to calling the new drug “female Viagra” or “pink Viagra.” While both flibanserin — to be marketed under the brand name Addyi — and Viagra treat differing forms of sexual dysfunction, those labels for the female drug are inaccurate and misleading.

Viagra and the other male impotence drugs, known collectively as PDE5 inhibitors, help to increase blood flow to the penis in men who are experiencing erection problems caused by insufficient blood flow. With the exception of Cialis for Daily Use, these drugs are taken as needed, roughly an hour before sexual activity is likely to begin. Clinical testing of these male drugs has shown them to be both effective and safe for use in the vast majority of healthy men.

Addyi Must Be Taken Daily

Addyi, however, must be taken daily to be effective, and the drug is designed to increase sexual desire in premenopausal women who have lost their interest in and desire for sex. Sexologists and family therapists have been quick to point out that the drug will do nothing to repair a problematic relationship or counteract the effects of some other medication that may be causing a loss of sexual desire.

Moreover, the clinical tests conducted to win FDA approval for Addyi showed that the drug achieved only modest improvements in female sexual desire, when compared with the effects of placebos. In one such trial, according to The New York Times, women taking the drug reported 4.4. “satisfying sexual experiences a month,” which compared with a rate of 3.7 such experiences reported by women given a placebo.

Rejiggers Brain Chemistry

Unlike the PDE5 inhibitors, which help to temporarily increase blood flow to the pelvic region, Addyi attempts to fire up the female libido by rebalancing the levels of certain neurotransmitters in the brain. Specifically, it reduces levels of serotonin, believed to inhibit female sexual desire, while increasing levels of dopamine and norepinephrine, both of which tend to promote sexual desire.

Written out on the blackboard above is the chemical formula for flibanserin, the active ingredient in Addyi.

Written out on the blackboard above is the chemical formula for flibanserin, the active ingredient in Addyi.

These male and female drugs also differ significantly in the severity of their side effects. Common side effects of the male impotence drugs include headaches, body aches and pains, diarrhea, indigestion, runny or stuffy nose, dizziness, and facial flushing. These adverse effects often disappear altogether upon continued use of the drugs. More serious side effects of the male drugs include changes or loss of hearing or vision or an erection that lasts four hours or more. However, the incidence of these more serious side effect is relatively rare and was not sufficiently worrisome to the FDA to prompt boxed warnings or other precautionary measures.

Conditions Attached for Female Drug

When the FDA gave the green light to Addyi on August 18, 2015, it attached a couple of significant conditions to its approval. Both were prompted by concerns about the drug’s adverse side effects in some women. The most serious of these side effects are dangerously low blood pressure and possible loss of consciousness. The likelihood and intensity of such side effects can be increased if the drug is taken concurrently with alcohol or other drugs that interfere with the breakdown of flibanserin in the body.

Addyi, which is scheduled to come to market in October 2015, can only be prescribed and dispensed under the drug regulatory agency’s risk evaluation and mitigation strategy (REMS) program. Physicians and pharmacists will need to undergo REMS training and be certified in the REMS program before they can prescribe or dispense the drug.

Boxed Warning Required

On top of the REMS restrictions, the FDA ordered that a boxed warning be printed on the drug’s packaging inserts to advise consumers of the risks of severe hypotension and fainting in patients who drink alcohol or use moderate or strong CYP3A4 inhibitors. Such inhibitors include certain drugs as well as grapefruit and grapefruit juice, all of which can affect the metabolism of medications such as Addyi.

Under the terms of its conditional approval for Addyi, the FDA also required the company that owns Addyi “to conduct three well-designed studies in women to better understand the known serious risks of the interaction between Addyi and alcohol.”

While not exactly a "pink Viagra," Addyi may in time help some women to increase their interest in and desire for sex.

While not exactly a “pink Viagra,” Addyi may in time help some women to increase their interest in and desire for sex.

On a positive note, two days after the FDA approval, Sprout Pharmaceuticals — the drug’s patent holder — and Canadian-based Valeant Pharmaceuticals jointly announced that they had reached an agreement for Valeant to acquire Sprout for roughly $1 billion. This is widely seen as a vote of confidence in the new drug, which is Sprout’s only product.

Sprout to Remain in Raleigh

Under the terms of the acquisition agreement, Sprout will be acquired by a wholly owned subsidiary of Valeant but will continue to operate from its present home base in Raleigh, North Carolina. Of Sprout’s new relationship with Valeant, Sprout CEO Cindy Whitehead said, “This partnership with Valeant allows us the capacity to now ensure broader, more affordable access to all the women who have been waiting for this treatment. Beyond building this in the United States, Valeant also offers us a global footprint that could eventually bring Addyi to women across the globe.”

Although millions of American women lobbied for Addyi’s approval, not all women expect the drug to deliver on its promise to treat hypoactive sexual desire disorder, or HSDD, the most common form of sexual dysfunction in women. Many of the drug’s opponents argue that its severe side effects outweigh its relatively modest benefits. Addyi’s foes also decried the manufacturer-funded public relations campaign to get the drug approved.

Gender Bias Alleged  

The primary thrust of the PR campaign was to protest what the drug’s proponents described as the FDA’s gender inequality in approving 20-some drugs to treat male sexual dysfunction but not a single drug to help women counteract their sexual problems. Pro-flibanserin organizations such as Even the Score and Women Deserve campaigned tirelessly for the drug’s approval, operating slickly designed websites to drum up support — and gather petition signatures — for the drug.

Some of Addyi’s critics contend that the drug reflects a fundamental  misunderstanding of how sexual desire works in women. In a “Science of Us”  article posted at NYMag.com, writer Melissa Dahl draws a distinction between spontaneous sexual desire and responsive desire. The former, writes Dahl, works as follows: “You just want it, out of the clear blue sky, and that internal drive motivates you to go out and get some.” However, that type of sexual desire seems to be much more common in men and considerably less common in women.

Dutch sex researcher Ellen Laan gets credit for pioneering the study of responsive sexual desire, “where arousal emerges not in anticipation of pleasure but in response to it.” Dahl argues that testimony from some of the women in flibanserin’s clinical studies indicates that their increased desire was responsive in nature and probably not attributable to the drug.

Photo credit: Day Donaldson

Don Amerman is a freelance author who writes extensively about a wide array of nutrition and health-related topics.

Don Amerman has spent more than three decades in the business of writing and editing. During the last 15 years, his focus has been on freelance writing. For almost all of his writing, He has done all of his own research, both online and off, including telephone and face-to-face interviews where possible. Don Amerman on Google+