The US Food and Drug Administration (FDA) has finally approved the libido-enhancing pill for women, colloquially known as "female Viagra", after being rejected twice.

Accompanied by a strong warning, the US regulator has said Flibanserin, produced by Sprout Pharmaceuticals, will be made available only through certified channels due to safety concerns. The drug, to be marketed as Addyi, is also the first FDA-approved treatment to increase sexual desire in women.

"Today's approval provides women distressed by their low sexual desire with an approved treatment option," said Janet Woodcock, 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."

The pill is specifically designed for pre-menopausal women, who are diagnosed with the condition known as hypoactive sexual desire disorder (HSDD), to regain the drive by stimulating brain chemicals. Though the drug was submitted to the FDA twice, it was not approved due to the side-effects which include nausea and dizziness.

Woodcock added: "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."

It's different for women

Although the drug is often dubbed as "Viagra for women", it is strikingly different from the blue pill for men. Addyi is more likened to anti-depressants such as dopamine and serotonin, and women are advised to take the pill each night.

On the other hand, Viagra, which boosts the blood flow to certain areas of the male body, is meant for men and is taken before indulging in sexual activity. While Viagra is primarily intended to treat the physical problem of erectile dysfunction, Addyi is aimed at activating certain brain pathways by working on the central nervous system.

The pink pill has sparked serious debates among experts, with some strongly against the drug.

"Women's sexuality is very complicated. It's not a matter of just taking that pill, by the way, and then all of a sudden the lights go on. You have to feel good about your body. You have to feel good about yourself. You have to feel the guy really loves you. ... It's complex. It's not the same as a man taking a pill," Judy Kuriansky, a clinical psychologist and certified sex therapist, told CNN.