The Federal Drug Administration approved two drugs for long-term weight loss, but researchers from the Dartmouth Institute for Health Policy and Clinical Practice are now questioning their safety after one-year trials.
The trials showed that randomization to either drug, in addition to a calorie-restricted diet and increased exercise, was associated with more weight loss than patients' randomization to placebos (3 percent more weight loss with lorcaserin; 7 percent more with phentermine/topiramate).
Both drugs have been associated with serious harms; both drugs' labels include warnings about memory, attention or language problems and depression.
The trials for both drugs could not exclude important cardiovascular harms. This is why neither drug is on the market in Europe, the researchers said.
The European Medicines Agency reported that it was unlikely to approve lorcaserin because of concerns about possible cancers, psychiatric disorders and heart valve problems, prompting the manufacturer to withdraw its application. The EMA explicitly rejected phentermine/topiramate twice - first in 2012 and again in 2013.
The researchers said the FDA shared many of these concerns and the agency did not approve either drug on their initial applications. On reapplication, some of the concerns were resolved but not those about serious cardiovascular harms. Nevertheless, the FDA approved the drugs and required the companies to conduct post-approval trials to assess the harms.
The study has been published in the JAMA Internal Medicine.
