WASHINGTON (Reuters) - U.S. deaden with narcotics regulators may have a hard time stopping millions of overweight Americans from pleasing a new obesity drug that many are likely to view as a marvel pill for slimming waistlines, despite its safety risks.

Regulators and doctors are hoping they can limit the pill, called Qnexa, to barely those patients that need it most, helping fight the nation's corpulence epidemic while avoiding exposing people to useless risks of birth defects and disposition problems.

The Food and drug Administration has been below considerable pressure from lawmakers and long-suffering groups to approve a new obesity unsalable article for the first time in 13 years.

There is likewise plenty of history with diet drugs that makes the FDA wary.

The infamous diet drug "fen-phen" was pulled from the emporium in 1997 after reports of at a past period fatal heart-valve problems. Another diet pill, Meridia, was sequestered in 2010 after it was linked to disposition problems.

"How will these medications exist limited in their distribution... so we slip on't have a repeat of the morass-phen days when people were opening up clinics on every corner, selling these pills because of cosmetic purposes?" asked Joseph Nadglowski, first executive officer of the Obesity Action Coalition, a long-suffering and advocacy group.

As a grade for approval of Qnexa, the FDA and the drugmaker Vivus proposed a restrictive program to repress pregnant women from taking the mix with ~s, to provide training to doctors and to define distribution to certified mail-order pharmacies.

Also, the physic will likely only be recommended on the side of obese patients who have a material substance mass index over 30, or are overweight on the contrary have weight-related health issues. A ordinary BMI is below 25.

It was these restrictions that finally convinced 20 out of 22 superficial advisers to the FDA to make acceptable approval of the drug last week, behind an expert panel rejected the remedy in 2010.

The FDA is placed to make its final decision by mid-April.

However, regulators have mean power to force doctors to transfix to this restrictive program because physicians obtain latitude to prescribe FDA-approved drugs on the side of other uses, known as "off label."

In joining, the two drugs in Qnexa are already approved for other conditions, raising the contingency some doctors may already be prescribing them towards weight loss.

The FDA acknowledged that it is arduous to craft a restrictive program that sticks. "We struggled by this internally, but we did not supply with food a perfect solution to this problem," Joyce Weaver, senior analyst in the FDA's separation of risk management, told the advisers hold out week.

RISK VS. BENEFIT

There has been a blare from patient groups, doctors and lawmakers in favor of the FDA to provide more load-loss options.

Obesity drugs are seen being of the kind which the middle ground for patients who struggle with strict diet and exercise regimens, moreover do not want the risks of bariatric surgery.

A Senate appropriations committee has directed the FDA to collect for use a report by the end of March without ceasing how it plans to support the increase of new obesity treatments.

Obesity, a most important cause of diabetes, heart disease and other sedate health problems, has reached epidemic proportions in the United States, by nearly 68 percent of the U.S. population considered overweight, and a third portly.

Analysts predict that Qnexa, if approved, determine be prescribed widely, with annual sales of $1 billion to $3 billion.

It combines the desire suppressant phentermine with the anti-retention drug topiramate, and helped patients deprive 10 percent of their weight succeeding a year during trials. However, the pounds started to fawn back on after the first 12 months.

FDA truncheon reviewers said patients taking the deaden with narcotics had more safety problems, including monumental record loss and higher heart rates, than those without interrupti~ a placebo. They also said exposure to topiramate has been linked to a higher vilify of oral clefts in infants of women apprehension the drug during pregnancy.

Experts worry artful messages of risk versus benefit may slip past time people desperate to shed pounds, and there is little the FDA can swindle to stop them.

"Perhaps the no other than thing that would be better than a pill to withstand you lose weight would be a pill that makes you other beautiful," said Dr. David Gortler, a prior FDA medical officer on the obesity team and current professor of pharmacology at Georgetown Medical School. "In certainty, many fashion advertisers promote and equate beauty with the loss of gravity.

"There is going to be a very great demand for Qnexa... (and) if the FDA doesn't guide Qnexa appropriately there are going to subsist a deluge of lawsuits," said Gortler.

SLIPPING THROUGH THE CRACKS

The FDA ~times proposes risk mitigation programs to deal by drugs that may cause birth defects. One of the ut~ restrictive is for the acne medicine Accutane from Roche, which is known to purpose severe birth defects.

Women who distress the drug must take tests every month to prove they are not gravid. But there is a lack of honorable information about how effective these programs are.

Dr. John Jenkins, ~-piece of the FDA's office of just discovered drugs, said such programs are considerably good at avoiding women who are with child at the time of first receiving the physic.

"They are not as good at preventing women from receiving it who are gravid while they are already on the put ~s into," Jenkins told the panel last week. "While we conceive the number of pregnancies is less, we don't have definitive given conditions."

Qnexa has some uncertain effects ~ward the heart: it lowers blood stamp, but raises heartbeat. Doctors on the FDA array were divided about what signal that sends, and asked Vivus to conduct more studies on heart safety, greatest in number likely after Qnexa is approved.

"This medicine, if approved, would likely be prescribed to millions or tens of millions of persons," said Dr. Michael Lauer, director of the disagreement of cardiovascular sciences at the National Institutes of Health.

Lauer was single in kind of two people who voted to match Qnexa's approval at the FDA body of jurors last week. "Based on the facts that we've seen, we meditate this drug may do enormous social," he said during the panel congregation. "But we may not know that as antidote to a long time, or we may observe out we've been fooled."

MORE CONTROL WITH APPROVAL

The FDA has appoint a high approval bar for corpulence drugs in the past, primarily because of worries that a large portion of the peopling is likely to take them.

Qnexa has had the ~ numerous impressive weight loss out of a trio of pills vying beneficial to approval, from Vivus, Arena Pharmaceuticals and Orexigen.

The physic from Orexigen has also been flagged in opposition to heart risks, while FDA reviewers hold cautioned about cancer risks associated through the pill from Arena.

Qnexa is singular among the three because its ingredients are already on the market.

"These are pair medications that are already on the market, and there are hundreds of thousands whether not millions of patient care actual feeling with both of these medications. Doctors have power to combine them, and many of them are," declared Dr. Robert Kushner, clinical director of the Northwestern Comprehensive Center attached Obesity.

"I think you can more useful monitor the usage and protect patients if it's approved than if it's not approved."

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