Total ear canal ablation and lateral bulla osteotomy were performed on a 29-kg, 6-year-old intact male mixed-breed dog. A 100-µg hour-1 fentanyl transdermal patch was applied to help manage pain. It was applied to the skin on the left lateral flank immediately cranial to the hindlimb. About 36 hours after surgery, the dog was extremely sedated. The patch was still attached, but the reservoir had been chewed open and the contents removed. The patch was removed, and the dog was monitored closely over the next 6 hours. He became more alert and seemed normal by 6 hours.

COMMENTARY: Transdermal patches are an effective way to provide analgesia, but they are not risk-free: In addition to consumption by the patient, there is risk for accidental exposure to children or others or abuse of the patches if sent home with the pet. Patches should be carefully applied and monitored, and owners should be advised of potential complications.

Accidental prehension and suspected transmucosal or oral absorption of fentanyl from a transdermal patch in a dog. Schmiedt CW, Bjorling DE. Vet Anaesth Analg 34:70-73, 2007.