The Food and Drug Administration is close to approving Qnexa, the first prescription diet pill in 13 years.
Earlier this week, a panel of medical experts voted 20-2 to put the drug on the market. But now, there are serious concerns about its side effects.
The FDA rejected the appetite-suppressing drug just two years ago for safety concerns. Studies have shown that on average, people taking Qnexa lost about 10 percent of their body weight in the first two years of use.
Frazier Harzell, 20, claimed the drug helped him lose 165 pounds in just one year.
"I went from 390 pounds to 225 pounds. It definitely changed my life," he said.
"If approved, Qnexa would be the most potent medicine we would have on the market to treat obesity. The currently available drugs are not very effective," said Dr. Tim Garvey, chairman of the Department of Nutrition Sciences at the University of Alabama at Birmingham.
Almost one-third of adults and 17 percent of children in the United States are classified as obese.
"We go from Weight Watchers to bariatric surgery and that leaves probably 65 million people who need a new option to address obesity," said Joe Nadglowski, president and CEO of the Obesity Action Coalition.
The panel advising the FDA said for obese people, the benefits of Qnexa outweigh the risks. However, opponents say the risks and side effects should not be taken lightly. They include increased memory loss, confusion, kidney stones, birth defects, and increased heart rate and heart palpitations.
The drugmaker Vivus said it will keep Qnexa away from women who might become pregnant because their babies would have a five times greater than normal risk of being born with a cleft palate.
Dr. Sidney Wolfe is currently the director of Public Citizen's Health Research Group, a consumer and health advocacy lobbying group. He's among those speaking out against the diet drug.
"In the studies that they've done so far, in the people that took this drug, there were five heart attacks, and the people that took a placebo, there were none," he explained.
The panel reports it is still unclear if the side effects lead to heart attacks and more serious cardiovascular problems.
The FDA has until April 17 to make its decision to make the drug available to the American public.