Belviq (Lorcaserin)

On June 27, 2012, the FDA approved a drug for the treatment of obesity. This is the the first drug that has been approved by the FDA for this problem since 1999. Many promising drugs were expected to be released and not approved for various safety concerns. In addition, one drug, sibutramine (Meridia), which had been approved previously, was withdrawn two years ago.

The fact that this is the first drug to be approved in 13 years is astounding. Obesity has increased dramatically. It is estimated that 65% of American adults, and 25% of teenagers, are overweight or obese.

We in the Medical Weight Loss community feel that the FDA has been overly stringent in the regulation of compounds to help treat obesity. All medications have some potential side effects, but the FDA doesn’t seem to care about the side effect of not treating the problem at all. Obesity leads to Diabetes, Heart Disease, breathing problems, arthritis, infertility, depression, and many cancers. Besides ruining millions of people’s lives with medical issues Obesity may be costing the Health care system between 100 and 500 billion dollars annually, and is a huge part of the reason that health care costs are out of control.

Belviq is a selective seratonin agonist. Specifically it has affinity for the 5-HT2c receptor. Stimulation of 5-HT receptors in certain brain cells causes a feeling of satiety and decreases caloric intake.

Belviq is chemically somewhat similar to fenfluramine. Fenfluramine was the second “fen” in “fen-fen”. Fenfluramine stimulates a slightly different receptor than Beliq,namely the 5-Ht2b receptor. This is critical, because it was shown that stimulation of the 5-HT2b receptor in heart cells could lead to heart valve problems, and this lead to the withdrawal of fenfluramine from the market in 1997.

The other “fen” in fen-fen is Phentermine, which increases levels of norepinephrine ( adrenaline). It is still available and in fact is the weight loss medication that I prescribe most frequently.

The FDA made the manufacturers of Belviq do many safety studies to prove that there were no heart valve effects of the drug. In a two year study, subjects had echocardiograms done every 3 months . The rates of people who developed cardiac valvular abnormalities were equal in the belviq and the placebo groups.

The most common side effect of belviq was headache. For some reason, people were also slightly more likely to develop colds on belviq. There was mild nausea. There seemed to be very few reports of insomnia or people feeling over stimulated, as can happen with other weight loss drugs.

My main concern with belviq is that there is no data looking at people trying both Phentermine and belviq in combination. After all, fenfluramine, the discontinued drug with some similarities to belviq, had been around since 1973, but the problems with it did not surface until it was combined with Phentermine as Phen -Fen in 1987. It is not unreasonable to assume that some Physicians will prescribe Phentermine and belviq together. I can even see a scenario where patients who want to be on both may see different doctors for the different prescriptions, and intentionally deceiving their doctors in order to be on both medications. A trial is urgently needed evaluating patients on both drugs.

At any rate, it is a good thing to finally have a new bullet in the chamber in the battle against Obesity.

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