Looks Like Best Week Ever for Maker of Female Libido Pill

— -- The company in North Carolina that received FDA approval this week for female libido drug Addyi may be having its best week ever. Two days after that milestone, it was just acquired today by a giant pharmaceutical company for $1 billion.

Valeant Pharmaceuticals International is paying about $500 million in cash for Sprout Pharmaceuticals, based in Raleigh, North Carolina, with the close of the acquisition deal and another $500 million early next year. The multi-national Valeant, which is based in Quebec and also owns Bausch + Lomb, said it will pay Sprout a share of future profits based on certain milestones.

The acquisition is sure to be a windfall for the husband-and-wife team that started Sprout and their small staff.

"I am extremely proud of the commitment and passion of our 34 employees who have been mission driven to get to this breakthrough first for women," Sprout CEO Cindy Whitehead said in a statement about the acquisition. "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."

Her husband, Robert, preceded her as CEO and serves as vice chairman of Sprout. Valeant said Sprout will stay headquartered in Raleigh and become a division of the publicly traded corporation.

Sprout, which received approval from the U.S. Food and Drug Administration for flibanserin, which will be marketed as Addyi in the United States, is the first of its kind in helping pre-menopausal women with hypoactive sexual desire disorder. Valeant said today it expects Addyi to be available in the fourth quarter of this year.

While sometimes referred to as the “female Viagra,” Addyi differs from that drug, which targets erectile dysfunction, a physiological problem. Flibanserin instead targets actual libido and sex drive. FDA's expert panel, which had twice rejected Addyi previously, had concerns about its risks.

Women using the drug can face rare but serious side effects, including nausea, dizziness, fatigue and fainting, according to the summary released by the FDA.

ABC News' Gillian Mohney contributed to this report.