Treatment with L-deprenyl prolongs life in elderly dogs.

Eighty two beagle dogs ranging in age from 2.8 to 16.4 years and in weight from 6.3 to 15.8 kg were allotted to 41 pairs and administered placebo or 1 mg/kg L-deprenyl orally once daily for 2 years and 10 weeks. When survivorship for all dogs in the study was analyzed there was no significant difference between the L-deprenyl and placebo treated groups, most likely due to the (expected) survival of virtually all young dogs in both groups for the duration of the study. To assess whether L-deprenyl treatment begun in later life might enhance canine longevity in a fashion similar to that documented in rodents we also examined survival in a subset of elderly dogs who were between the ages of 10 and 15 yrs at the start of tablet administration and who received tablets for at least 6 months. In this subset, dogs in the L-deprenyl group survived longer (p < 0.05) than dogs in the placebo group. Twelve of 15 (80%) dogs in the L-deprenyl group survived to the conclusion of the study, in contrast to only 7 of 18 (39%) of the dogs who received placebo (P=0.017). Furthermore, by the time the first L-deprenyl treated dog died on day 427, 5 placebo treated dogs had already succumbed, the first on day 295. Specifically with respect to dogs, the findings reported herein suggest daily oral administration of 1 mg/kg L-deprenyl prolongs life when begun in relatively healthy dogs 10-15 years of age and maintained for the duration of the individual's life, but in any event for no less than six months.