Ceftiofur Side Effect in a Mare–Case Report

Adverse drug reactions in horses are rare. The antimicrobials are in the list of the most common drugs associated with reaction in horses. The aim of this report is to describe the clinical presentation of an adverse drug reaction after the intramuscular administration of ceftiofur hydrochloride. A 5-year-old crioulo broodmare at one day postpartum presented signs of difficulty to walk, positive pulse in the four limbs, and heart rate of 80 beats per minute (bpm), with a history of fighting with another mare. The clinical suspicions were rhabdomyolysis and laminitis. Initially a dose of flunixin meglumine was administrated intravenous to prevent an endotoxemia. On the same day, the blood collection showed an elevated number of white blood cells, predominantly neutrophils and monocytes. An antimicrobial treatment with ceftiofur hydrochloride at a dose of 2.2 mg/kg intramuscular was applied. At the first day, the mare does not show signs of drug side effect. However, 24 hours later, in the second application, the patient presents incoordination, dizziness, and loss of equilibrium. At the same time, dexamethasone was administrated. The signs were reverted, and the mare was normal after the reaction. The treatment with ceftiofur was changed to enrofloxacin, and the animal had a complete recovery. These drug reactions are not common in the routine of equine clinical practitioners, but they cause a great preoccupation for the owner and the veterinarian. •Drug reaction in a crioulo broodmare after ceftiofur intramuscular administration.•First report of a cephalosporin side effect causing signs of incoordination and loss of equilibrium in horse.•Severe signs of incoordination in a mare after ceftiofur administration.