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

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 (SpO 2 ). TD supplied the effective anesthesia duration for ≥ 42 minutes, which can be fully reversed by atipamizole.