Another new diet drug being tested
Reminiscent of the fen-phen diet drug, phentermine (the "phen" of "fen-phen") is being used in combination with the anticonvulsant drug topiramate in hopes of being the new diet drug. In a recent announcement, Vivus, the developer of the drug combination known as Qnexa, says patients lost an average of 37 pounds a year. In the first trial, EQUIP, of the drug involving 1,200 obese patients, there was an average of 14.7 percent weight loss, but only at the higher doses. In the second trial known as CONQUER, approximately 2,500 patients received the drug combination and showed an average of 30 pounds of weight loss, again at the highest doses.
Phentermine, a stimulant, has the ability to act as an appetite suppressant. But it can also increase blood pressure and heart rates. That was why it was prescribed with fenfluramine during fen-phen. The fenfluramine, Pondimin, counteracted the stimulant effect. In this new drug combo, Topiramate is the downer. Topiramate is best known as an epilepsy drug which gained increased off-label use when some studies showed it had a beneficial "effect on binge eating and weight reduction."
The worrisome aspect is the lack of reliable long-term safety data. If Vivus decides to go ahead with further testing of the combination and get approval for the combination, then the Food and Drug Administration (FDA) will require further safety testing. However, that is a big IF. And the fact is that Phentermine and Topiramate are FDA approved drugs. While they have not been approved in a combination form by the FDA, there is nothing which prevents doctors from prescribing the combination now. That is what happened in Fen-Phen. Two FDA approved drugs were used in combination for long term use without reliable long term safety data. When the studies were finally done, they showed major problems with cardiovascular risk as well as increasing the risk of a deadly disease known as primary pulmonary hypertension.
The weight loss industry is a billion dollar industry and our society is always looking for the quick fix. Unfortunately, the answer does not lie in a drug combination. If a drug were the answer, you would have to take the drug for the rest of your life. I have yet to see any study showing any drug or drug combination keeps weight off after you quit taking the drug. In fact, studies upon studies have shown that when a person quits taking a pill or goes off their diet, the weight is regained plus more. This is called the rebound effect. The only way to counteract that rebound effect is exercise and changes in eating habits.
So there is the problem. If you have to take these drugs for a long period of time to lose the weight AND keep it off, where is the safety data showing long term safety? Currently, there is none. Until there is long-term safety data showing the safety of using these drug in combination for long period of time, people should not take the combination for weight loss nor should doctors prescribe it.
Hopefully, the FDA will closely monitor any future trials as well as step up vigilance to ensure the manufacturers of Phentermine and Topiramate are not promoting this off-label combination use of the drugs.
Reported by Robert M. Kisselburgh, Mississippi Injury Attorney
