VIRGINIA BEACH -- Pets are part of the family, so it's no surprise that many people will do almost anything to keep them healthy.

Experts say about 45 percent of America's pets are overweight, which can lead to pet problems that sound human ones -- arthritis, diabetes, heart disease, high blood pressure and a shorter lifespan.

Oz, a three-year-old lab mix, is fighting the battle of the bulge. At 78 pounds, he was 18 pounds overweight.

Veterinarians generally say a dog is obese if it weighs 20 percent more than its ideal weight.

Even with exercise and a proper diet, Oz wasn’t losing weight. So, his owner took the drastic step of putting him on a doggie diet drug.

Slentrol is the first FDA-approved drug to help dogs lose weight.

"It ties up 10 percent of the fat that's absorbed in the intestinal cell. And it also blocks the appetite centers so it reduces their desire to eat," explains Ron Hallstrom, DVM, a veterinarian at Dog and Cat Hospital in Norfolk.

Oz is his vet's first patient on Slentrol.

“If we catch it now, we notice it's a problem, hey we need to do something to benefit his life, we can potentially prolong it in the future," says Oz's owner Catherine Dierks of Va. Beach.

Just like a person, exercise helps dogs get fit.

Bederra, an Australian Cattle Dog, is slim and trim now, but she wasn’t always that way.

"She will eat all day long if she could. I mean, if there was a doggie buffet, she would go to it every day!"

Owner Christine Prieur of Va. Beach says food has to be stored in a cabinet or put in a locked trashcan.

"She literally went through the entire trash can and it was strewn over the entire kitchen floor," she recalls.

Bederra's not a bad dog. It's just that her owners have a hard time resisting their pooch's pleadings.

Veterinarians recommend creating a canine exercise routine.

Once a week, Bederra goes to Holly Ridge Manor Canine Country Club in Va. Beach for some old-fashioned exercise.

With a combination of daycare, daily exercise and controlled feedings, Bederra has lost 7 pounds and weighs what she should weigh: 35 pounds.

She’s on a strict diet of 2 cups of food for indoor dogs, twice a day.

For Oz, combining Slentrol with exercise, he’s lost five pounds in two weeks.

"I've noticed he's got a little more energy.  He kind of wants to get in stuff a little bit more."

Slentrol, a liquid, was approved in January 2007.

Slentrol's initial dose is given for the first 14 days. After that, the vet will assess the dog's progress at monthly intervals, adjusting the dose depending on the dog's weight loss. Once the goal is achieved, the drug's manufacturer, Pfizer, recommends continued use of the drug during a three-month period. During that time, the veterinarian and owner should establish the right amount of food and physical activity the dog needs.

As with most drugs, animal or human, there are potential side effects. According to the FDA, Slentrol may cause vomiting, loose stools, diarrhea, lethargy and loss of appetite.

It costs $62 per bottle.  How long it lasts depends on how much the veterinarian recommends be used per dose.

Slentrol is approved for canines, not humans. The FDA says there are many adverse reactions associated with human use, including abdominal distention, abdominal pain, diarrhea, flatulence, headache, nausea and vomiting.

Slentrol also isn't designed for cats.

After seeing story promotions on WVEC-TV, Carol Andrews wrote in about her experience with Slentrol.

Family Photo

Carol Andrews says her dog, Hunter, would not have been able to have knee surgery without losing weight.

She says the diet drug helped Hunter, her beagle, slim down 20 pounds in four months (from 59 pounds to 39 pounds) ahead of knee surgery.

She writes:

"He is like a new dog! He now enjoys his walks again and can jump up on the sofa for a well-deserved knap. He even chases his younger brother, Tucker, who is a Jack Russell Terrier. Mr. Energy himself.

I wish all the people that try this for their dogs have great success as well."