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FDA To Discuss Obesity Drug Qnexa

This morning, the US FDA Endocrinologic and Metabolic Drugs Advisory Committee will discuss the safety and efficacy of new drug application (NDA) 22-580, proposed trade name QNEXA (phentermine/topiramate) Controlled-Release Capsules, manufactured by VIVUS, Inc., as an adjunct to diet and exercise for weight management in patients with a body mass index (BMI) equal to or greater than 30 kilograms (kg) per square meter or a BMI equal to or greater than 27 kg per square meter if accompanied by weight-related comorbidities.

Background material for this hearing are available here.

More details on this meeting are available here.

It will be of interest to see how the panel decides to vote.

Washington, DC


  1. One of the biggest struggles treating people with mental illness is keeping them on their meds. And you know why? Because psych meds are simply dreadful. Although I understand topomax is primarily a migraine drug, it also has a lot of use for psychiatric disorders.

    30 BMI is way, way too low to put yourself through topomax, especially if you have no co-morbidities. It’s notorious for cognitive side effects — so much that I’ve seen it nicknamed “Dopamax,” “Stupamax” and the “Barbie Doll Drug” because it makes you skinny and stupid. the weight loss is a bug, not a feature.

    I’m also concerned that the bar for “weight-related comorbidities” seems to get defined down all the time. What used to be normal blood pressure is now “pre-hypertensive.” Would that be considered enough if your BMI was higher than 27? I simply don’t know.

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  2. Thanks for these links and information, Dr. Sharma! I recognize the two drugs (phentermine, of course, from olden days fenphen)–Topirimate seems very popular with pro-ana bloggers and ED patients, so I suspect there is indeed some *efficacy* in terms of reduced appetite; however, the potential long-term potential side effects (problems/damage) remain unknown.

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  3. I find it very scary that half of fenphen is under consideration as a diet drug again. Doesn’t anyone remember that fenphen caused heart valve damage in 1/4 to 1/3 of the people who used it?

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  4. I have to jump in here and vigorously defend your advocacy. Although I believe that the topiramate component of Qnexa is likely to ultimately cause Qnexa to be stigmatized as an intolerably lethargenic agent (for most people), I still believe that it is a step in the proper direction and the the FDA advisory committee acted properly. Obesity and its deadly concomitant, metabolic syndrome, are too dangerous to remain ignored by modern pharmaceutical science.

    As for the objections raised herein by other posters, I respond thus:

    1: Phentermine is the demonstrably safe half of fen-phen and has no chemical or pharmacologic similarity to fenfluramine (the “unsafe” half of fen-phen).

    2: Topamax is a bit of a “stupid pill”, and this, I think, will prove to be Qnexa’s biggest problem, BUT… not all patients seem to mind the side effects of topiramate and the subjective effects seem to subside over time.

    3: To suggest that you are “pro-ana” (meaning a promoter of anorexia nervosa) is offensive and even a casual perusal of you writings herein show that assertion to be false.

    Anyway, thanks for the excellent blog and the courageous advocacy.

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