Effect of dexmedetomidine hydrochloride on tiletamine hydrochloride-zolazepam hydrochloride anesthesia in alpacas

OBJECTIVE To evaluate the effect of IM administration of a tiletamine hydrochloride-zolazepam hydrochloride (TZ) combination with either dexmedetomidine hydrochloride or saline (0.9% NaCl) solution (SS) on the motor response to claw clamping, selected cardiorespiratory variables, and quality of recovery from anesthesia in alpacas. ANIMALS 5 adult sexually intact male alpacas. PROCEDURES Each alpaca was given the TZ combination (2 mg/kg) with dexmedetomidine (5 [D5], 10 [D10], 15 [D15], or 20 [D20] mu g/kg) or SS IM at 1-week intervals (5 experiments); motor response to claw clamping was assessed, and characteristics of anesthesia, recovery from anesthesia, and selected cardiorespiratory variables were recorded. RESULTS Mean +/- SEM duration of lack of motor response to claw clamping was longest when alpacas received treatments D15 (30.9 +/- 5.9 minutes) and D20 (40.8 +/- 5.9 minutes). Duration of lateral recumbency was significantly longer with dexmedetomidine administration. The longest time (81.3 +/- 10.4 minutes) to standing was observed when alpacas received treatment D20. Following treatment SS, 4 alpacas moved in response to claw clamping at the 5-minute time point. Heart rate decreased from pretreatment values in all alpacas when dexmedetomidine was administered. Treatments D10, D15, and D20 decreased Pao(2), compared with treatment SS, during the first 15 minutes. During recovery, muscle stiffness and multiple efforts to regain a sternal position were observed in 3 SS-treated and 1 D5-treated alpacas; all other recoveries were graded as excellent. CONCLUSIONS AND CLINICAL RELEVANCE In TZ-anesthetized alpacas, dexmedetomidine (10, 15, and 20 mu g/kg) administered IM increased the duration of lack of motor response to claw clamping, compared with the effect of SS.