Anesthetic effects of dexmeditomidine-tiletamine/zolazepam combination in cats undergoing ovariohysterectomy

Abstract

Common injectable anesthetics in cats are alpha-2 receptor agonists and tiletamine/zolazepam. Xylazine shows higher rate of side effects because its lower specificity to alpha-2 receptors than dexmeditomidine. However, the use of drug combinations in cats is not much known. Therefore, alternative anesthetic combination should be investigated. Here, we examined the use of tiletamine/zolazepam with two doses of dexmedetomidine in cats. A total of 24 female cats, weight 3.05 ± 0.10 kg (mean ± SEM). Cats were randomly blinded given intramuscularly injection (IM) with either of such drug combination, representing dosage of low dose dexmedetomidine 7.5 μg/kg with tiletamine/zolazepam 3 mg/kg; TD-Lo (n=8), high dose dexmedetomidine 15 μg/kg with tiletamine/zolazepam 3 mg/kg; TD-Hi (n=8), or xylazine 0.6 mg/kg with tiletamine/zolazepam 3 mg/kg; TX (n=8). After the IM injection, the sedative, analgesic, and cardiorespiratory effects and body temperature were assessed. All treatments showed clinically comparable induction effects resulting in spontaneous lateral/sternal recumbency and loss of paw withdrawal reflex within 7 minutes; TD-Lo (4.125 ± 0.74 min), TD-Hi (4.5 ± 0.32 min), and TX (4.12 ± 0.58 min). Notably, anesthesia time or the time from absent to regain of paw withdrawal reflex (Time LOPR to ROPR) was significantly higher in TD-Hi (52.75 ± 1.17 min) compared to TD-Lo (42.62 ± 2.51 min) and TX (41.12 ± 2.53 min); p<0.01. Likewise, a significant higher of time from IM to ROPR in TD-Hi (57.25 ± 1.29 min) were indicated vs in TD-Lo (46.75 ± 2.88 min; p<0.05), and vs in TX (45.25 ± 2.43 min; p<0.01). No vomiting or any adverse events were reported in all groups. TD-Lo, TD-Hi, and TX produced overall comparable cardiorespiratory effect with no significantly differences in all physiological values; heart rate (HR), respiratory rate (RR), body temperature (T), systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), and tissue oxygen saturation (SpO2). TD supplied the effective anesthesia duration for ≥ 42 minutes, which can be fully reversed by atipamizole.