After a drought of 13 years, the Food and Drug Administration has approved two diet drugs in just under three weeks to help Americans in their battle of the bulge.
The first drug, Belviq, known chemically as lorcaserin, which was approved in late June, is an appetite suppressant that works by activating brain receptors for serotonin, a neurotransmitter that triggers feelings of gratification and satisfaction.
Qsymia, approved on Tuesday, is a combination of two drugs approved long ago by the FDA: phentermine, an appetite suppressant, and topiramate extended release, which is used for seizures, migraines, and bipolar disorder but was discovered to also cause unintentional weight loss.
In clinical studies, according to published reports, patients on Qsymia lost more weight, dropping from an average 227 pounds to 204; on Belviq, patients went from an average 220 pounds to 207.
"But you must bear in mind they were not studied head to head, so you can't make firm conclusions that one is necessarily better than the other," said Allegheny General Hospital internist Marc Itskowitz, whose practice includes many obese or overweight patients.
Both drugs have potential side effects.
Most common side effects of Belviq are headache, fatigue, nausea, dry mouth, dizziness and constipation. The FDA also has ordered manufacturer Arena Pharmaceuticals to conduct six studies once the drug reaches the market to determine whether it causes heart attacks or stroke.
Qsymia (pronounced kyoo-SIM-ee-uh) caused some patients in the clinical trial to suffer increased heart rate and metabolic acidosis, a condition that can lead to fatigue, hyperventilation and anorexia. It must not be used during pregnancy because it can damage a fetus; nor can it be used in patients with glaucoma or hyperthyroidism. Other common side effects include tingling of hands and feet, dizziness, altered taste, insomnia, constipation and dry mouth.
The pharmaceutical industry's track record on diet pills has been troubled with approved drugs being pulled from the market when dangerous side effects have surfaced after their wide distribution. The drug combination known as fen-phen was withdrawn in 1997 after more than 30 percent of patients on the combo developed heart valve problems that could lead to heart failure or death and Meridia was pulled in 2010 after being linked to heart problems.
So with these newly approved diet medications, which one should a patient take?
"When I prescribe, it's on an individual basis," said Vicki March, the doctor who directs the weight-loss program at Magee-Womens Hospital of UPMC. "I'd want to try [Belviq] on patients. It's possible it's very effective, that it works with some people and not with others. We have so few [drugs], we don't have much choice. It's very nice to have a choice. Neither one is a great one in patients with heart disease, unfortunately. ... People can get kidney stones with topirimate."
Dr. Itskowitz said, "If you're going to choose one, Qsymia did show better effectiveness in clinical trial, and the medications have been FDA approved for many years, so Qsymia is more likely to be used than Belviq for those reasons."
But both doctors stressed that drugs alone are not the answer to the nation's tremendous weight problem -- it has been estimated that one-third of Americans are obese.
"I think drugs are only part of the answer," Dr. Itskowitz said. "They must be counseled how to eat" and be on an exercise program.
"It's extremely important to incorporate a lifestyle change" with a drug, Dr. March agreed. "It has to be under the supervision of a physician under a very focused and very definite structured diet and exercise program.
"You can always eat through these medications."
The FDA approved both drugs for use in adults with a body mass index of 30 or more, the definition of obese, or adults with a BMI of 27 or greater (overweight) who have at least one weight-related condition such as high blood pressure or type 2 diabetes. That does not mean, however, that doctors can't prescribe them for patients with lesser BMIs.
But Drs. Itskowitz and March stressed that the FDA guidelines should be followed.
"They should not be used in patients who are only mildly overweight, 10, 15, 20 pounds overweight. They should be counseled, not be exposed to medications," Dr. Itskowitz said.
"I think you are walking a slippery slope if a general practitioner starts prescribing to patients with a BMI of 25 to 27," Dr. March said. "I like to do lifestyle change first and then add something if necessary."
Pohla Smith: firstname.lastname@example.org or 412-263-1228.