AN arthritic pooch is back to her bouncing best after shedding the pounds with the world's first anti-obesity drug for canines.

Nine-year-old Megan, a pedigree Samoyed, started piling on the puppy fat when she began suffering from joint problems.

Her aching limbs meant that she was not able to move around as much as she used to and, although she was eating less than the recommended amount for the breed, she was still putting weight.

Owner Cassie Apps, 52, of Somerville Road, Walcot, said: "I think it's absolutely fantastic.

"When your dog is overweight a lot of people think you're stuffing it full of food but that really isn't always the case."

The new medicine is only licensed for dogs but its makers are developing another one for cats.

The drug, Yarvitan, costs £50 for an eight-week course and must be prescribed by a vet.

Mrs Apps was told about Yarvitan when she took Megan to the Drove Veterinary Surgery.

Since going on the course Megan, who was one of only five dogs in the country to take the first batch, has lost eight kilograms, going from 43kg to 35kg - and she is still shedding the weight.

"She actually wants to go out now," Mrs Apps said. "She is back to her old self. We are going to keep her as active as we possibly can and hopefully this will carry on."

The drug is administered as a liquid that is simply poured over the dog's food.

Owners give it to their dog twice a day for three weeks, followed by a two-week break, and then another three weeks of the drug.

It works by blocking the transfer of fats from the food dogs eat into their bloodstream, without affecting the absorption of the vital nutrients they need every day.

The treatment also slightly reduces the dog's appetite, meaning that it is less likely to beg for treats.

"I'm very grateful to the Drove surgery and I would recommend it to anybody," said Mrs Apps. "There have been no side affects.

"She looks beautiful and she's even more beautiful on the inside. She loves everybody and everything. Anything you care to put in front of her she thinks is wonderful."

The drug's developer Janssen-Cilag claims that Yarvitan can reduce the chance of a dog developing arthritis and can increase the life expectancy of an obese dog by 18 months.