For the pup who enjoys kibble a bit too much

FDA approves first treatment designed to help slim down overweight canines

WASHINGTON -- Millions of Americans rely on diet remedies to try to lose weight. As soon as April, millions of their dogs will, too.

Pfizer Animal Health , part of Pfizer Inc. , the globe's largest drug company, is betting that Slentrol will help overweight and obese dogs shed pounds. The Food and Drug Administration yesterday approved the once-a-day liquid formulation as the first-ever prescription drug treatment in the United States for dogs who need to shed pounds. A daily dose of the treatment will cost $1 to $2.

The potential market for Slentrol is huge. The American Veterinary Medical Association , which conducts an annual canine census, reported in 2002 that Americans owned 61.6 million dogs. About 35 percent are overweight or obese , tipping the scales at 5 to 20 percent over their ideal weight. Like humans, those extra pounds increase dogs' chances of suffering from heart disease , breathing problems, and arthritis .

"The approval of Pfizer's medicine really is a recognition of the serious and widespread issue of canine obesity," said George Fennell , a vice president in the company's US companion-animal division.

Plus, veterinarians see another eerie, if anecdotal, parallel: Tubby owners have chubby dogs.

But Fennell warned that Slentrol is "not a passport" to abandon healthy diet and vigorous exercise.

Overweight dogs will be given the drug under the guidance of a veterinarian. The dose depends on how much the animal weighs. After its ideal weight is reached, the dose will be reduced over three months as better diet and exercise regimes are used to maintain the weight loss.

Slentrol works by disrupting the process that creates fat and unleashes it into the bloodstream, curbing appetite and lowering fat. As the dogs tested in trials of the drug became slimmer, Fennell said, owners reported seeing renewed "puppylike behavior" and a restored ability to do things like climb steps.

Drug companies have been offering magic bullets against human obesity for years without success, and it is unclear whether this attempt to slim canines will work any better. The clinical trials have been short, even in dog years, so there is little evidence about long-term effect.

Low-fat dog foods, which have been on the market for years, have not stemmed the obesity epidemic in dogs, especially in breeds most likely to transform from scrawny puppy to pudgy adult -- such as Labradors , hounds and beagles . The special diets haven't trimmed dog weight much more effectively than Atkins , Slim-Fast, and South Beach diets do for humans.

Consider the case of Clancey . Until he died at age 15, the 92-pound basset hound had struggled to keep off extra pounds all of his life, said his owner, Tracie Cone. He once nearly drowned in her pool, unable to paddle his short legs fast enough to stay afloat.

"He sunk like a rock" and she had to pluck him out, said Cone, 49 , an organic wine producer  in California .

"Basset hound owners across America will be lining up for this drug," Cone said.

Diedtra Henderson can be reached at dhenderson@globe.com