UPDATE [1/10/12]: The FDA announced this week that a major contraindication has been lifted from the weight loss drug Qnexa, broadening the potential market for the drug. Previously, the FDA was concerned that women of childbearing age who ingested one of the drug’s ingredients might have children with a higher rate of birth defects, but further research has shown the danger is only present for women who took the drug during pregnancy. Some experts expect the drug will be approved by the spring.
There is a new weight loss drug on the horizon. Qnexa, from parent company Vivus, Inc., consists of a combination of two prescription drugs – Phentermine and Topiramate. It has been effective in clinical studies at helping those who take it lose up to 15 percent of their body weight. There have also been indicators of increasing some cardiovascular actions. In addition, Qnexa also appears to improve sleep apnea, a condition in which those who suffer can stop breathing during their sleep cycles.
Phentermine is well known by dieters, but Topiramate has not been used in the weight loss field. It is prescribed as an anti-convulsant, but patients who have used it have reported weight loss as a side effect. It is also prescribed under the name Topamax for migraine use. Combining the two medications together has shown to increase the weight loss results of either drug when it was taken singly. Multiple levels of each drug have been combined in field testing, and the company feels that they have found the “magic” levels.
Qnexa works as an appetite suppressant, allowing a patient to eat markedly less and still feel full. It’s been hailed as the most effective weight loss medication since Fen-Phen.
In 2010, Qnexa was turned down in its first application to the FDA advisory board, due to marked safety concerns. These included possible birth defects, depression and memory impairment. The FDA does not always follow the recommendations of the advisory board, but it is a more common than not practice. In light of this, the FDA requested that Vivus, Inc. complete further testing on the possible negative side effects on a pregnancy.
Topiramate has been shown to cause cleft palate birth defects. Subsequent investigations by Vivus, Inc. showed that the rate of birth defects was lower than previously reported and the FDA agreed to allow the company to resubmit the drug.
In April 2011, a third study on the efficacy of Qnexa was released. It showed that, over the course of the two-year duration, those who took the medication experienced lower blood pressure and improved lipid levels. Based on these numbers, the FDA accepted the second application of Qnexa as a weight loss drug in October 2011 and set it for a five-month trial period.
The FDA is scheduled to make its decision on Qnexa in April 2012. If Qnexa is approved, it will not be available to women of childbearing age.