SEATTLE - Dogs in the Pacific Northwest are being inducted into trials for a new drug that has shown to significantly lengthen the lives of lab mice.

The drug, rapamycin, improved heart health and seemed to delay the onset of some diseases in older mice. Scientists aren’t sure if the same results will translate for canines. There’s even a chance it could do more harm than good.

Even so, the potential side effects aren’t stopping some pet owners from embracing a chance to keep their best friends around for a bit longer.

The early results in aging dogs seem to indicate that rapamycin is helping, according to biologists involved in the trials.

Dogs age faster than humans with bigger dogs aging faster than smaller dogs. 40 dogs participated in the pilot rapamycin trial in Seattle. The dogs participating in the study had to be at least six years of age and weigh at least 40 pounds.

Symptoms of aging shown by the test canines included graying muzzles, arthritis and loose skin.

Over 1,500 dog owners applied to have their furry friends participate in the research trial of rapamycin. Earlier trials have used mice, bacteria, flies and worms as subjects. In the previous study, younger mice were able to live about 25 percent longer than control mice when given a certain dosage of the drug. Animals taking the drug in that test were less likely to develop certain types of cancer, kidney disease, obesity and their hearts functioned better for longer.

A month before the study concluded, no major side effects had been observed by the dogs. Even those receiving the highest dosage were free of significant problems that could be tied to the drug. Compared with control animals, the hearts of the dogs taking rapamycin were pumping blood more efficiently by the end. Now that the pilot run has ended, researchers are looking to enroll 450 more dogs to carry out a much more comprehensive five-year study. Funding for this study must be acquired first.

As of yet, there are no plans for a human trial of the drug as the risks are considered too high. However, scientists involved in the project feel that many people would be willing to take that risk if the payoff scales to a potential 20 to 30 percent increase in longevity.