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3.75 mg of phentermine plus 23 mg of topiramate caused weight loss of 5.1% vs 1.6% with placebo
Saturday, November 05, 2011 1:27 pm Email this article
Obese men and women given 3.75 mg of controlled-release phentermine plus 23 mg of controlled-release topiramate (Topamax) -- the trade name of this drug combination is Qnexa -- lost an average of 5.1% of body weight after one-year compared to an average weight loss of 1.6% for those given a placebo according to a study from the researchers at the University of Alabama at Birmingham. Listen To This Story
Audio highlights of this study
Audio highlights of this study are posted here.
Is Sustained-Release Important?
Does it matter that these drugs were sustained-release? No.
Does it matter that these drugs were sustained-release?
The reason they are using sustained released versions of these drugs is to make their product unique.
It does NOT make it more effective, and, I would guess that it even makes it LESS effective.
Immediate-Release Diet Pills vs Sustained-Release
Immediate-Release PPA was twice as effective as Sustained-Release PPA
A review by the FDA of the drug phenylpropanolamine (PPA)—which was banned in 2000 because a study from Yale in conjunction with the FDA claimed that it increased the risk of hemorrhagic stroke, but the study was fatally flawed in many ways which made the results meaningless which was never revealed—found that immediate-release PPA caused twice as much weight loss per week as sustained-release PPA, suggesting that, as a general rule, immediate-release appetite suppressants are more effective than sustained-release.
This makes perfect sense because if you are going to use an appetite suppressant, you want to be able to take it an hour before eating, and then have it peak in the blood right when you are eating in order to get the maximum appetite suppressing effect at that time.
Why Are Immediate-Release Appetite Suppressants More Effective?
Why are immediate-release appetite suppressants more effective than sustained-release?<
The reason that sustained-release appetite suppressants are probably less effective as a general rule are that they take several hours for them to peak in the blood—the drug is being slowly released—which, if you take it an hour before eating, does not peak until several hours AFTER you have eaten.
An Exception: Sustained-Release vs Immediate-Release Diethylpropion
Sustained-release diethylpropion (Tenuate Dospan, 75 mg) as effective as immediate-release diethylpropion (Tenuate, 25 mg)?<
One exception to this general rule seems to be with sustained-release diethylpropion (Tenuate Dospan, 75 mg) versus immediate-release diethylpropion (Tenuate, 25 mg).
Weight loss with sustained-release diethylpropion (Tenuate Dospan, 75 mg) appears to be just as good as, and possibly slightly better than, immediate-release diethylpropion (Tenuate, 25 mg).
My guess as to why this is, is because diethylpropion is converted in the body to phenylpropanolamine (PPA) in the body, which causes the appetite-suppressing effect, which may take several hours, and therefore it suppress appetite at the next meal.
Do Not Be Fooled Into Thinking that Controlled-Release Phentermine and Topamax are Better
Do not be fooled into thinking that controlled-release phentermine and topiramate are more effective; my guess is that they are probabaly LESS effective<
The point of discussing this is that I don’t want you to be fooled into thinking that just because they used controlled-release phentermine plus controlled-release topiramate (Topamax) in this study, that it is somehow more effective than the immediate-release phentermine plus immediate-release topiramate (Topamax) that is available right now.
My guess is that the controlled-release phentermine plus controlled-release topiramate (Topamax) is NOT more effective, and is likely to be LESS effective than the immediate-release version of these drugs.
Other articles about phentermine plus Topamax
Here are some other articles about phentermine plus Topamax.
Allison D, Gadde K, Garvey W, Peterson C, Schwiers M, Najarian T, Tam P, Troupin B, Day W. Controlled-release phentermine/topiramate in severely obese adults: A randomized controlled trial (equip). Obesity (Silver Spring). 2011 Nov 3, published on-line.
AUTHOR’S CONTACT INFORMATION
1] Department of Biostatistics, School of Public Health and Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA  Department of Nutrition Sciences, School of Health Professionals and Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA.
Departments of Biostatistics and Nutrition Sciences, Nutrition Obesity Research Center
University of Alabama at Birmingham
1665 University Boulevard
Birmingham, AL 35294-0022, USA
Obesity Clinical Trials Program
Duke University Medical Center
Durham, NC 27710, USA
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