Acomplia, which was rejected last year by an FDA panel, was linked to five deaths by the UK’s Medicines and Healthcare products Regulatory Agency since the pill went on sale two years ago.

There were 720 reports of adverse drug reactions, some of which involved more than one side effect, bringing the total to more than 2,100. Five cases were fatal, including one suicide. The data, covering reports from the June 2006 introduction to May 9, was released on the MHRA web site.

“We are working closely with the FDA to match the requirements,” Alexandre Moreau, a Sanofi vice president who oversees the marketing of diabetes products, tells Bloomberg News. “We’ve been in close contact with them. Acomplia is not for everybody so we’re working to identify the right patient target.”

The Acomplia news could damp the prospects for a similar diet pill Merck is developing, called taranabant, which is linked to psychiatric side effects. Tony Butler, a Lehman Brothers analyst, handicaps the chances the FDA will approve taranabant at 25 percent. “I think there’s this ‘How do we let a drug out onto the market that may cause some depressive symptoms,’ feeling at the FDA, and they don’t have an answer to that yet,” he tells The Wall Street Journal.

Sanofi doesn’t have similar data from other countries, a Sanofi spokesman tells Bloomberg. The UK, Germany and France are the biggest consumers of the medicine, according to the MHRA.

The UK agency said that depressive reactions may occur in as many as 10 percent of patients. After regulators reviewed data last year, the pill’s label was strengthened to warn about use in patients with major depressive disorder or on antidepressants, and doctors were told treatment should be stopped if patients became depressed, Bloomberg notes.

According to the National Health Service, which provides medical care to citizens in England and Wales, there were 101,000 prescriptions written for the 20-milligram dose of Acomplia last year in England. That doesn’t include use in Wales, Scotland or Northern Ireland.

UK medical advisers backed restricted funding for Acomplia in March, saying the drug shouldn’t be used for longer than six months unless a patient lost at least 5 percent of his or her body weight in that time and not for longer than 2 years in total without assessment