Targeting weight loss: Earlier this year, the FDA granted approval for two diet pills

Wednesday, December 5, 2012
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It's a stark reality: More than a third of Americans are obese. And, as we've all been told countless times, obesity contributes to a number of other health conditions, such high blood pressure and diabetes, among others.

As America combats this growing (no pun intended) epidemic, the Federal Drug Administration in July approved new weight-loss drugs for the first time in 13 years.

Belviq and Qysmia, which are now available by prescription, are both intended for long-term use. In essence, once a person begins taking one of the drugs, they must be taken for the rest of that person's life.

"These are the first drugs approved for chronic use," says Dr. Philip Tippen, an internal medicine physician with Saint Francis Medical Center. "Typically phentermine (a component of Qysmia) is used just for three to four months, as the FDA says it's for short-term use."

Tippen explains how the drugs work: "Belviq works by stimulating a specific type of serotonin receptor in the brain (the serotonin 2C receptor specifically). This appears to reduce one's appetite. Qysmia is a combination of two older drugs, phentermine and topirimate (Topamax, a drug used for headache prevention and epilepsy). Phentermine is a stimulant and reduces appetite due to its stimulant effects. Topirimate suppresses appetite, too, and thus was noted as a side effect in patients being treated for migraines or epilepsy."

Belviq and Qysmia aren't intended for just anyone. To be a candidate for either drug, a patient must be at least 18 years old and have a body mass index (BMI) of 30 or greater, or have a BMI of 27 or greater and at least one other weight-related condition. In addition, the FDA recommends discontinuing treatment after 12 weeks if a patient fails to lose 5 percent of her weight.

According the FDA, the average weight loss for patients in Belviq trials was 3 percent to 3.7 percent over those taking the placebo. In the case of Qysmia, the average weight loss ranged from 6.7 percent (lowest dose) to 8.9 percent (recommended dose) over those taking the placebo.

As with any drug, side effects are a concern, and the same is true for Belviq and Qysmia, Tippen says.

"Side effects are the main concern that I have with Belviq," he says. "Stimulation of serotonin receptors is how fenfluramine and dexfenfluramine worked, which affected and damaged heart valves (this was the 'fen' in Phen-fen). Supposedly Belviq is more specific for the serotonin receptors in the brain and that's why FDA approved it, but I would be cautious until the drug is used on a wider basis."

As for Qysmia, the phentermine can raise heart and blood pressure; it also can be abused as a stimulant drug. And, it's important to note, the drugs shouldn't be seen as a magic bullet for weight loss.

"All these drugs are supposed to be used as an adjunct to diet and exercise," Tippen says. "I don't plan on prescribing either one of these drugs. ... The majority of patients that I have seen regain the weight because they don't make the necessary lifestyle changes. It is a lifelong challenge to eat healthy and maintain a healthy lifestyle and just taking a pill doesn't do that."