This week, an FDA advisory panel voted 20-2 to recommend approval of a new weight loss pill, called Qnexa. Qnexa is a combination of two previously available medications that seem to work together well: phentermine and topiramate. Phentermine is a stimulant, while topiramate is often used for migraine headaches. What’s interesting is that in 2010, this same drug was rejected by a similar FDA committee.
While the drug seems effective, with most patients losing about 10% of their overall weight after a year on the drug, there are concerns about side effects, particularly on the heart. Studies of Qnexa shows that it raises the heart rate, and can cause palpitations – an effect common to many weight loss medications. It’s unknown whether the medication causes an increased risk of heart attack or stroke. In addition, topiramate has been linked to birth defects, particularly cleft lip and palate. FDA estimates the medication would cause cleft lip / palate in about 5 out of 1000 births, which is at least double the typical rate.
While the FDA is not obligated to follow the recommendations of the committee, they usually do. The final decision is expected later this year. Of course, the FDA may attach a number of restrictions to any approval – such as follow-up studies on cardiac side-effects, or stringent requirements for use of birth-control pills for women that want to use Qnexa. We’ll have to wait and see.
photo credit: CNBC.com