Successful management of lisdexamfetamine intoxication in a dog despite complications of hypoglycemia and rhabdomyolysis.

Abstract

A 15-year-old castrated male beagle-cross dog was presented with neuromuscular, cardiovascular, and gastrointestinal signs 7 h after accidental ingestion of a toxic dose (33 mg/kg) of the amphetamine lisdexamfetamine dimesylate. Clinical and clinicopathological abnormalities noted included dysphoria, mydriasis, hyperesthesia, muscle tremors, tachycardia, tachypnea, hyperthermia, hematochezia, mild hypoglycemia, hemoconcentration, and metabolic acidosis. Initial treatment with intravenous (IV) acepromazine, butorphanol, methocarbamol, and rectal cyproheptadine, along with IV fluids with 5% dextrose added, was inadequate to control clinical signs. The dog was stabilized effectively following administration of IV constant-rate infusions (CRIs) of dexmedetomidine (1 to 3 μg/kg per hour) and butorphanol (0.2 mg/kg per hour). The dog was maintained on this CRI protocol for 20 h and weaned off without redeveloping neuromuscular and cardiovascular signs. Serum biochemical analysis and urinalysis at that time revealed marked elevation of creatine kinase (100-fold), mild to moderate elevation of liver enzymes (ALP: 2.4-fold, ALT: 9.5-fold, GLDH: 4-fold), and the presence of myoglobinuria, indicative of rhabdomyolysis and possible concurrent hepatic injury. The animal recovered with supportive care and was discharged 44 h after presentation. One week after discharge, the dog was clinically normal and serum biochemical analysis and urinalysis confirmed resolution of rhabdomyolysis. No evidence of kidney failure secondary to the rhabdomyolysis was noted. To the best of the authors' knowledge, this is the first report of survival following lisdexamfetamine intoxication in a dog. Clinical signs resolved completely with supportive and symptomatic therapies mainly consisting of IV fluid therapy and sedative administration. There were no long-term complications reported. Key clinical message: Aggressive medical therapies, including IV CRIs of dexmedetomidine and butorphanol, in addition to IV fluids, were effective for managing a dog with severe lisdexamfetamine intoxication. The dog recovered uneventfully following 44 h of hospitalization, with no evidence of long-term complications secondary to the rhabdomyolysis associated with the toxicosis.