Induction and Recovery Characteristics and Cardiorespiratory Effects of Verapamil on Ketamine-Induced Anaesthesia in Dogs

The present study was designed to evaluate the induction and recovery characteristics as well as the cardiorespiratory effects of verapamil on ketamine-induced anaesthesia in dogs. Six healthy male mix-breed dogs weighing 19.5 +/- 3.0 kg and aged 1.5-2.5 years were used in a randomized crossover design. After premedication with acepromazine (0.025 mg/kg) and morphine (0.25 mg/kg) intramuscularly, dogs received either treatments of verapamil (0.1 mg/kg; IV) or normal saline intravenously. Anaesthesia was induced with ketamine (10 mg/kg; IV) and maintained with isoflurane. Induction and recovery quality were acceptable in both treatments. Recovery tended to be prolonged in verapamil compared with SAL. Heart rate in normal saline, after administration of ketamine, showed significant increased values (P<0.05); whereas, heart rate was relatively stable in verapamil with no significant changes (P >= 0.05). Mean arterial blood pressure, during inhalation anaesthesia, was below the reference ranges and showed significant decreases in both treatments (P<0.05). Respiratory rate decreased in both groups at several time points compared with the base (P<0.05). It was concluded that addition of verapamil to ketamine, had no effect on induction and recovery quality and could potentially prolong recovery. Verapamil resulted in relatively stable HR compared to that of control group.