Addyi, the pink pill for women with low libido, was approved by the Food and Drug Administration last month even though at least three FDA reviewers recommended rejecting it.
They warned about possible side effects and expressed concern that "the marginal clinical benefits do not outweigh the serious risks," according to a memo posted online that summarized the analysis within the U.S. regulatory agency.
More than a dozen offices reviewed the drug, though the memo doesn't make clear how many people raised concerns. One reviewer particularly wanted more study of the interaction between Addyi and alcohol because the tests were conducted almost exclusively with men.
While such disagreement isn't typical, "it does happen," said Ira Loss, a pharmaceutical analyst with Washington Analysis, a research company that evaluates the impact of public-policy change on financial markets. The FDA had rejected the drug, chemically known as flibanserin, in 2010 and 2013 before approving it in August, so the dissenters were "not alone in their view. FDA gives them the right to say what they feel, and higher-ups make the decision."
Two years ago, there was internal dissent when the FDA approved Bristol-Myers Squibb Co. and Pfizer Inc.'s blood thinner Eliquis. A decade ago, there also was division over the safety of Merck & Co.'s Vioxx painkiller, which has since been taken off the market, and Sanofi's antibiotic Ketek.
"The FDA encourages robust scientific discussions among our staff," Andrea Fischer, an FDA spokeswoman, said in an e-mail. "In most cases, alignment on a decision is achieved through discussion as reviews proceed," but the official administrative file will reflect "differences of opinion if they exist."