Given the CDC estimate that over one-third of the U.S. adult population is obese, the availability of weight-loss drugs has been a controversial topic. According to the Mayo Clinic, weight-loss drugs are generally prescribed for patients with Body Mass Indices (BMIs) above 30. Some proponents of weight-loss drugs claim that for certain patients, these medications are necessary in order to reduce their weight, while others argue that weight-loss medications may substitute for strict exercise and diet regimens. However, few weight-loss drugs on the market have actually been proven to be effective.
Among the over-the-counter (OTC) drugs available, only Alli (the OTC form of Orlistat) has been shown to be truly effective, while other OTC treatments such as bitter orange and guar gum are listed as “probably ineffective” on the Mayo Clinic’s website. Among prescription drugs, diethylpropion (Tenuate) and phentermine (Adipex) are FDA-approved only for short-term use (up to 12 weeks). According to the Mayo Clinic, the sole FDA-approved drug for long-term obesity treatment is Orlistat (prescription drug Xenical). According to PubMed Health, Orlistat is prescribed in combination with a low-fat, low-calorie diet and exercise program in order to help people lose weight. In addition, the drug can be taken to avoid regaining weight that has already been lost, according to PubMed Health. However, the paucity of drugs on the market raises an important question: have pharmaceutical companies been unable to find more drugs to target obesity, or has the FDA been too cautious in regulating these medications?
First, it is important to recognize that weight-loss drugs often cause unpleasant and sometimes serious side effects. The prescription drugs Tenuate and Adipex decrease appetite and increase both blood pressure and heart rate, according to the Mayo Clinic website. Even the only FDA-approved drug, Orlistat, works by acting as a lipase inhibitor, blocking the absorption of fat in the intestine but also causing patients to lose control over bowel movements, according to the Mayo Clinic website and an article in the International Journal of Obesity. Moreover, according to a 2008 article in the New England Journal of Medicine entitled the “Nonsurgical Management of Obesity in Adults,” those taking prescription weight-loss drugs will only see up to a 5% increase in weight reduction compared to a placebo. The researchers cited that patients who take such drugs that affect hormones and neurological pathways may also experience drug dependence, which represents another potential health risk. These side effects highlight the inherent risks of weight-loss drugs, which the FDA must evaluate before approving a drug for use on the market.
Recently, in fact, the FDA experienced an infamous drug crisis following its approval of the drug Fen-phen. In the 1990s, Fen-phen (fenfluramine/phentermine) was marketed heavily as a powerful weight-loss drug, according to a Frontline article. However, after reports of heart valve dysfunction and pulmonary hypertension in patients taking Fen-phen surfaced, and once a 1997 piece in the New England Journal of Medicine found that the drug may be associated with cardiac valve dysfunction, the FDA banned the drug in 1997, according to the FDA website.
The Fen-phen crisis is now being discussed once again as the FDA decides whether or not to approve the drug Qnexa, which the FDA previously rejected in 2010 due to cardiovascular side effects, according to a recent New York Times article entitled “Advisory Panel Favors Approval for Weight-Loss Drug.” According to a briefing document, a federal advisory panel approved the drug this past February with a vote of 20-2. According to the New York Times article, if approved by the FDA, Qnexa could become the “first new prescription drug to treat obesity in 13 years.” The article points out that the drug is particularly well-touted for leading to an average of a 10% weight loss in clinical trials, nearly twice that of the drugs currently on the market.
In spite of Qnexa’s promising prospects, it remains to be seen whether the FDA will approve Qnexa for use in U.S. drug markets. “The consequence of making a mistake here is huge,” Dr. Michael S. Lauer, a cardiologist at the National Heart, Lung and Blood Institute, told the Times. Indeed, the regulation of weight-loss drugs is a difficult issue to navigate not only due to its economic ramifications but also since the FDA must weigh the medical benefits and risks of these drugs. Ultimately, the debate over Qnexa reflects the larger role of the government—simultaneously ensuring the protection of its citizens while affording them the consumer freedom necessary to improve their health through the pharmaceutical treatment they deem best.