Dispatch: What's Up With All These Drug Combos?

An experimental obesity pill that combines the anti-addiction drug naltrexone and the anti-depressant bupropion has resulted in substantial reductions in body weight among participants in a clinical trial, the Lancet reports. Those on Orexigen Therapeutic's drug, Contrave, lost an average of 5 to 6 percent of their body weight over 56 weeks, compared to a 1.3 percent average weight loss among those taking placebos. Both groups had been advised to eat less and exercise more.

"Nobody knows why the treatment seems to be effective for obesity," says ACSH's Gilbert Ross. "We're seeing a rash of these combination drugs. We had Qnexa, combining topimerate and phentermine, and now we have this. How come all of a sudden we're seeing all these drug combinations for obesity?"

ACSH's Jeff Stier wonders if combinations of existing drugs are being tested because pharmaceutical companies are afraid the standard of safety has been set so high for new products. But pointing out the case of Fen-phen, Dr. Ross notes just because two drugs can be used safely separately doesn't mean they should be combined. ACSH staffers promise to make further inquiries for our curious readers.