One-third of our patients are obese. Perhaps more than any other group, primary care clinicians are painfully aware of the staggering health and financial costs associated with this disease. Obesity is a disease, not a lifestyle choice. Obesity is the second most important cause of preventable mortality in the United States after tobacco. Our patients are literally dying under their own body weight.
I feel frequently overwhelmed and incapable of addressing weight issues amidst the myriad of other clinical issues. Most of my patients have heard my diet and exercise spiel and have already been referred to the dietician numerous times. A recent patient asked if I could just “fix it with a pill.” This may be an indictment of modern medicine interacting with unreasonable patient expectations. For some patients, however, medication may be the only or the best option.
Last month, the American Journal of Clinical Nutrition published an article evaluating two-year outcomes of combination therapy with phentermine and topiramate (Am. J. Clin. Nutr. 2012;2:297-308).
Phentermine was a component of the infamous “fen-phen” (fenfluramine/phentermine) combination that was withdrawn from markets worldwide because of several concerns including cardiac valvulopathy. Valvulopathy was likely mediated through the serotonergic effects of fenfluramine on heart valve serotonin receptors. Phentermine was not associated with this effect and is still available on the market, currently Food and Drug Administration-approved for the short-term treatment of obesity. Phentermine is a psychostimulant (DEA Schedule Class IV) with an appetite suppressing effect. Topiramate (TPM) is an anti-epileptic that has a well-researched effect on weight loss likely mediated through appetite suppression. TPM also appears to have an effect on energy balance and metabolic rate leading directly to body fat reduction. In this study, subjects with a BMI (27-45) and at least 2 weight-related comorbidities who participated in a previous 56-week randomized, placebo-controlled study of phentermine/TPM were continued on their assigned medication or placebo for another 52 weeks. Groups were: lifestyle intervention + placebo; lifestyle intervention + 7.5 mg phentermine/46 mg (controlled release) TPM; or lifestyle plus 15 mg phentermine/92 mg controlled-release TPM. A total of 676 patients (78%) in the previous study agreed to enroll in this extension study.
At week 108, phentermine/TPM was associated with significant and sustained weight loss. Percentage changes from baseline in body weight were –1.8%, –9.3%, and –10.5% for placebo, 7.5/46, and 15/92, respectively. Significantly more phentermine/TPM treated subjects at each dose achieved at least 5%, at least 10%, at least 15%, and at least 20% weight loss compared with placebo (P less than 0.001). Phentermine/TPM improved cardiovascular and metabolic variables and decreased the incidence of diabetes. The combination was well-tolerated.
The phentermine/TPM combination of medication is currently being considered by the FDA as a new drug application for obesity. On February 22, 2012, an FDA advisory committee voted 20:2 to recommend that FDA approve phentermine/TPM as an obesity treatment. However, the FDA does not have to follow the recommendation of their advisory committee. In fact, a previous obesity medication combination (bupropion/naltrexone) received an FDA advisory committee vote of 13:7 in favor of approval, but the FDA rejected it based upon cardiovascular concerns related to bupropion.
The benefit of phentermine/TPM combination of medication for the treatment of obesity is established. What the FDA needs to do is thoughtfully weigh the risks of this combination against the risk of having limited options in our armamentarium to combat the obesity epidemic. We have a lot of endovascular stents being approved to treat the sequelae of obesity, but few options to treat the disease. If this medication combination alleviates the burden of obesity on patients and the medical system, isn’t it worth the risk? Our patients need options and many of them are running out of time.
Dr. Ebbert reported having no conflicts of interest.