Weight Loss Drug QNEXA Is Effective, but With Side Effects: Study

April 11, 2011 Updated: April 11, 2011

Weight loss drug QNEXA may be effective in instigating weight loss and lowering blood pressure and cholesterol in patients compared to a placebo, drugmaker Vivus, Inc. has said, citing a recent study.

Researchers as part of a CONQUER trial studied nearly 2,500 obese patients and found that those that used the weight loss drug QNEXA lost an average of 22 to 28 pounds after 56 weeks.

Patients given a placebo averaged 4 pounds of weight loss, said the study.

"We observed significant weight loss, improvements in co-morbidities and a reduction in the need for concomitant medications in patients treated with QNEXA," Dr. Kishore Gadde, lead researcher of the trial and director of obesity clinical trials at Duke University, said in a statement.

Such co-morbidities that QNEXA allegedly lowered the probability of are "cardiovascular, metabolic and inflammatory risk factors," the Vivus statement noted.

The trial, conducted in 93 locations across the United States, concluded that QNEXA, a "combination of phentermine and topiramate … might be a valuable treatment for obesity that can be provided by family doctors."

However, side effects noted included dry mouth, constipation, insomnia, and dizziness.

QNEXA, an oral drug that Vivus says controls appetite and satiety for overweight and obese patients, was rejected for approval by the FDA in October of last year over concerns that the weight loss drug contributed to irregular heart rates and abnormal fetal development in pregnant women.

Results of the study were published online in the medical journal The Lancet on April 11.

Last summer, during an initial review of the drug, an FDA panel rejected QNEXA, citing concerns regarding potential cardiovascular risks that the drug might pose.