Use of venlafaxine in the management of refractory intraspecific aggression in a multi-cat household

Abstract

Venlafaxine was evaluated as an alternative treatment for intraspecific (intercat) aggression in a multi-cat household. The patient, a 13.5 month old female spayed domestic short-haired cat, was initially treated with fluoxetine, a selective serotonin reuptake inhibitor, at doses up to 6 mg (1.5 mg/kg) per os every 24 h. Lower doses were tolerated but ineffective at managing the patient’s response to the other cat and at the 6 mg (1.5mg/kg) dose, the patient had increased agitation and aggression towards the owners. Consequently, the patient was weaned from fluoxetine and treatment with venlafaxine, a serotonin norepinephrine reuptake inhibitor, was initiated at 3 mg (0.7 mg/kg) per os every 24 h and increased to 6.25 mg (1.5 mg/kg) every 24 h after a week. Treatment was continued at this dose for 4 months then increased to 12.5 mg (2.7 mg/kg) per os every 24 h due to insufficient improvement despite environmental management and behavior modification. The patient tolerated this dose without reported adverse effects. After a month of treatment, the owner reported no further episodes of aggression and the patient has remained stable for over a year. This outcome supports venlafaxine as a well-tolerated and effective treatment option for intraspecific aggression in feline patients.