At a time when researchers are unearthing the true role of fat cells – once believed to be simple storage vessels – a new drug may help doctors get a handle on pet obesity. Morbid obesity – such as beagles that should weigh 40 pounds but clock in at 100 – is a medical condition; it is no longer simply about nutrition, said Debra Zoran, DVM, PhD, who presented research on a new obesity drug produced by Pfizer at the North American Veterinary Conference (NAVC) last week.

The Food and Drug Administration (FDA) approved Slentrol (dirlopatide) early in January and released the news on its website. International coverage of the drug – complete with jabs at lazy Americans who opt for medication over exercise – ensued but stories did not address the underlying issue of obesity, which is what Slentrol is designed to do, Zoran explained.

The new drug, scheduled to hit the United States veterinary market between April and June of 2007, is intended to get pets over the hump of weight gain when “obesity has gotten control of the dog,” Zoran explained. Materials and spokespeople emphasize that Slentrol should be used in conjunction with calorie restriction, safe and regular exercise, and behavior modification. Zoran added that doctors should be armed with more than calorie restriction for morbidly obese pets, who could injure themselves with any type of exercise.

She reviewed research conducted by Pfizer, which shows that the liquid, oil-based drug is safe for dogs to take for one year and stressed that it is not safe for patients on steroids, cats or people. Zoran did not take questions after the session and said that Pfizer representatives would address specifics when the drug was ready for sale.

Client education is essential to successful use since Slentrol reduces appetite and can cause vomiting within the first few weeks, Zoran said. Doctors must be actively involved in the use of this drug with regular visits to reweigh and reevaluate dogs and adjust dosage, she added. “There is no uniform application of this drug,” she said and added that patients can lose one to two percent of their body weight per week. “You have to prepare owners for this or there will be concern,” she said.

Sarah Abood, DVM, PhD (nutrition) hesitates to endorse or comment on the new obesity drug because, as she said, exercise and behavior modification must be part of any plan to reduce weight. As a nutritionist, Abood would prefer to see veterinarians and pet owners emphasize prevention versus treatment and worries that pet owners will assume that administration of the drug is all they have to do.

“Ill be reserved on recommendations for a medication that is indicated for obesity when I dont yet know if the owners will or have changed their behaviors at home,” Abood said. “Both feeding management and exercise behaviors must be understood before veterinarians include this type of medication in an obesity therapy program.”

For maintenance she suggests that, “pets on an obesity therapy program should be weighed every two weeks until weight loss is documented. Then they should be weighed every three to four weeks. The veterinarian and owner should be checking in with each other on a very regular basis.”

Zoran provided NAVC audience members with a brief explanation of the science behind Slentrol, which works in the gastrointestinal track to reduce uptake of fat. It also helps reduce appetite, which can be triggered by hormones released by fat cells in morbidly obese pets.

“You can’t just take the food away,” Zoran emphasized. “Their bodies are telling them that they need more [food.]” In addition to addressing underlying factors, Slentrol can give pet owners confidence that their efforts are working. “Seeing results increases chances of success,” she added. As a result, ongoing suggestions of exercise and a reduced calorie diet or prescription diet are more likely to be followed.

“It is not to be used alone,” Zoran said. “You need to use all tools [including diet, exercise, and behavior retraining along with the drug] in order to have success.