An advisory panel to the FDA recently approved the diet pill Qnexa, and now the drug is awaiting final approval by the agency. Qnexa is a combination of two drugs: phentermine and topiramate. The drug was denied approval a few years earlier because of concerns over serious side effects, such as an increased risk of heart attacks and birth defects. The advisory panel's reversal was based on the positive effects of weight loss associated with the drug and the improvement of certain medical risk factors, such as elevated blood sugar and blood pressure. The company which markets the drug, Vivus, is planning a two year study on the risk of increased heart attacks, but the FDA advisory panel is permitting the study to take place after the drug is approved. Some of the known side of effects of topiramate, (short term memory loss and decrease in cognitive function) were apparently not considered serious enough to prevent approval.
If Qnexa is approved, it would create a very short list of FDA approved diet drugs, as currently the only other approved drug in that category is Xenical, manufactured by Roche. Xenical aids weight loss by preventing fat absorption from the intestinal tract. The somewhat distasteful side effects that result when high fat-foods are not absorbed into the body have prevented the drug from being widely used. Moreover, Xenical has no direct effect on food intake such as removing hunger or increasing satiety.
Phentermine, a component of Qnexa, has been used alone as a diet aid. It is distantly related to the amphetamine class and suppresses hunger. Although never officially sanctioned by the FDA as a weight loss drug, it has been prescribed for dieters for years, and the internet is filled with advertisements promoting its effectiveness. Topiramate, the other component of Qnexa, is used to control epileptic seizures and migraines, although it has also been prescribed to help people suffering from bipolar disorder. When used by people with mood disorders, it was found to increase satiety. Topiramate's cognitive impairment side effect was an oft-noted potential problem, but combining it with the stimulant phentermine may counteract that unpleasantry.
Ideally, the reduction in hunger, decreased food intake and increased vigor experienced by dieters on Qnexa permits an easy adjustment to eating smaller portions, ignoring high calorie junk foods and increasing physical activity on a regular basis. This constellation of changes in eating and exercise, if habitual, could lead to permanent weight loss and a healthier life style. The question is: Will these changes persist once the patient stops taking the weight-loss drug? The newspaper article quoted a few patients who gained weight after stopping treatment, but of course most people gain weight after stopping whatever weight-loss program they have been following. Recidivism (the regaining of weight) ranges from 95 to 99% during the five years following a diet, and often exceeds the original weight that prompted a diet in the first place.
It seems that the answer depends on who is treated with a weight-loss drug. Certainly people whose health is at risk because of their weight would benefit greatly from an easy way of losing enough pounds to improve their cardiovascular, diabetic, and orthopedic status. If enough weight is lost so that a patient can exercise without pain, or lose the carbohydrate cravings often associated with diabetes, then theoretically the dieters should be able to continue losing weight after the drug treatment has stopped. We have seen how gastric bypass surgery can transform patients almost paralyzed by their obesity into physically active, healthy individuals, and a safe appetite-suppressant drug might be able to accomplish the same goal as a less intrusive and less expensive therapy.
But there are caveats.
Dieters must commit themselves to making better food choices, controlling portion size and adhering to an exercise routine once treatment with a weight-loss drug ends. It is very easy to resist eating doughnuts, ice cream cones or bacon double cheeseburgers with French fries while being treated with a drug that minimizes hunger and cravings. But once the drug treatment ends, it will be much harder to ignore the temptations of high-fat foods and cravings for sweets. Moreover, phentermine increases energy so that going to a gym or running up and down stairs seems doable. But will the dieter continue to exercise when the stimulant is no longer being administered?
No drug is going to remove the situational, emotional, hormonal and even seasonal triggers to overeating. As I often tell my weight-loss clients, "Unless you have a brain transplant along with your weight-loss treatment, your brain is going to be just as vulnerable to overeating when you are thin as when you were fat." So when the weight-loss drug is no longer prescribed, what is going to prevent weight gain?
Even though all physicians and clinics dispensing weight-loss medication insist that their patients follow healthy low-calorie diets and exercise, rarely does a weight-loss facility provide personal on-going therapy and life coaching necessary to help the patient avoid, minimize or deal with the situations that caused the obesity. Nor do these clinics have exercise physiologists to help the patient increase lean body mass to compensate for muscle loss caused by dieting.
The debate about the safety and effectiveness of weight-loss drugs will continue as new ones enter the market and, as with Qnexa, old ones are reevaluated. But in order for the obesity epidemic to slow down, patients and their physicians must realize that no drug, no matter how effectively it removes hunger or increases satiety, is going to solve the problem of what to do when life gets in the way of weight loss.