Ivermectin toxicosis in a dog.

Ivermectin, a broad-spectrum antiparasitic agent, was believed responsible for signs of CNS dysfunction in a dog. Within 2 hours of oral administration of ivermectin, the dog had hind limb ataxia. Neurologic signs progressed rapidly until the dog was in a semicomatose state at admission 20 hours later. The dog improved gradually under supportive care. The ivermectin had been given for suspected endoparasitism. Clinical signs were similar to those reported in dogs with clinical and experimental exposure to ivermectin.