An article set for publication in the respected journal, Nature Medicine, says that while Acomplia (rimonabant) may turn out to be the "Prozac of obesity," it still faces the challenge of overcoming "skepticism about its side effects."

The article notes the troubled past of obesity drugs, ranging from misuse of amphetamines to the "fen-phen debacle of the mid-1990s, when one component of the popular pill combination was found—but only after several years on the market—to cause irreversible heart valve damage."

While the developer of Acomplia, Sanofi-Aventis, has two years of safety data from clinical trials that concluded last year, U.S. and European regulators currently weighing approval of the drug are thought to still be concerned about the possibility of adverse effects developing during long-term usage.

Participants who lost significant amounts of weight in clinical trials of Acomplia regained the weight when they stopped taking the pill, suggesting that to keep weight off, people will have to continue on Acomplia indefinitely.

The most common side effects reported during the Acomplia clinical trials were nausea, dizziness, diarrhea and joint pain, which researchers described as "mild and transient."

But Nature Medicine reports that when drugs target the central nervous system to control appetite, "how they influence peripheral function only comes out after people have been on the drugs for a period of time," according to Jeffrey Bland, president of Metagenics, a California-based maker of nutritional products.

The journal also took note of reports by researchers that ten participants taking Acomplia in the clinical trials dropped out because of depression, compared to two participants in the clinical trials taking placebos.

"In a 2005 survey of 142 doctors conducted by Decision Resources, a Massachusetts-based pharmaceutical market research firm, more than 80 percent listed depression triggered by the drug as their primary concern; insomnia ran a distant second at 45 percent," the journal reported.