Potential seizurogenic effect of tramadol in a dog with necrotizing meningoencephalitis

A Jindo dog (8-month-old, intact male) was referred for hind limb lameness on the right side. The dog was diagnosed with a simple femoral fracture by radiological examination. After surgical fixation of the femoral fracture, tramadol: a narcotic-like synthetic analgesic was intravenously administrated for post-operative analgesia. After injection of the tramadol, generalized tonic clonic seizure was immediately occurred in the dog. Seventeen hours later, the dog died despite intensive care. We suspected that tramadol might induce the seizurogenic effect resulted in death. A necropsy was performed to examine the cause of the death. In consequence, the dog was diagnosed as necrotizing meningoencephalitis (NME) based on histopathological examination. We would be concerned that tramadol may be related to seizure activity in the NME patient. From this case, it is known that although tramadol has been proven to be a safe and effective agent for the control of pain in veterinary medicine, it would be carefully used to patient with history of neurological diseases including meningoencephalitis, hydrocephalus, and encephalopathy.