Safety study of a beef-based chewable tablet formulation of ivermectin and pyrantel pamoate in growing dogs, pups, and breeding adult dogs.

To determine the safety of a new combination of ivermectin and pyrantel (as pamoate salt) in a novel beef-based chewable tablet formulation, 3 tolerance trials were conducted and included growing dogs, pups, and breeding adult dogs. Growing dogs, given the combination orally for 5 consecutive days at recommended dosages (5 mg of pyrantel/kg of body weight, 6 micrograms of ivermectin/kg) or at twice the pyrantel dosage in combination with the recommended dosage of ivermectin, had no adverse effects. The combination also was administered to 6-week-old pups at 1, 3, and 5 times the recommended dose on 3 successive days for 3 times in 1 month. Compared with age-matched controls, treatment had no effect on clinical status, growth rate, or gross or histologic features. Breeding male and female dogs given the combination at 3 times the recommended dose for extended periods had no adverse effects, and prevalence of abnormalities in the offspring was not greater than that in nonmedicated controls.