Objective: To evaluate cardiorespiratory effects of intramuscular (IM) administration of romifidine/butorphanol (RB) in cats with and without atropine (A).

Design: Healthy, adult DSH cats (1.9-4.0 kg, 3 F, 3 M) were assigned to each of 2 treatments.

Procedure: Baseline data were recorded, and saline solution or A (0,04 mg/kg) was given SC. After 10 minutes, RB (40 ug/kg and 0.2 mg/kg, respectively) was given IM. Heart rate (HR), respiratory rate (RR), rectal temperature (RT), oxyhemoglobin saturation (SpO2), systolic, dyastolic and mean arterial pressure (SAP,DAP,MAP) were recorded at 10, 0, 5, 10, 20, 30, 40, 50 and 60 minutes after RB administration. Data were analyzed by use of analysis of variance for repeated measures followed by Student´s T tests.

Results: With or without A, HR decreased significantly, 5 and 20 minutes after administration of RB, respectively. RR decreased significantly after 10 minutes in both groups. MAP increased following administration of RB, whereas DAP decreased in both groups. With and without A, RT and SpO2 did not change after administration of RB.

Conclusions: In healthy cats, administration of RB causes bradycardia and bradypnea; but increases mean arterial pressure.