Sedative and echocardiographic effects of intranasal or intramuscular administration of dexmedetomidine in healthy cats

Objectives The aim of the present study was to evaluate the sedative and echocardiographic effects of dexmedetomidine (DEX) administered via intranasal (IN) and intramuscular (IM) routes in cats. Methods This randomised, blinded crossover study involved eight healthy adult cats. Cats were randomly allocated to receive DEX 10 μg/kg via either the IN or IM routes. Sedation, mechanical nociception and muscle relaxation were subjectively assessed and physiological variables recorded at baseline and at 5 min intervals for up to 40 mins after drug delivery. Echocardiography was performed 15 mins after delivery. Results In both treatment groups, sedation assessment scores significantly increased compared with baseline values ( P <0.05). At 25–35 mins after delivery, only the IN group exhibited a significant decrease in mechanical nociception scores compared with baseline ( P = 0.041, P = 0.042, P = 0.026). DEX delivery via both routes resulted in significant reductions in pulse rate ( P <0.05). In the IM group, mean arterial blood pressure measurements 35–40 mins after delivery were significantly lower than baseline ( P = 0.012, P = 0.012). Fractional shortening significantly decreased in both the IN and IM groups compared with baseline ( P = 0.016 and P = 0.049, respectively). Both routes caused reductions in cardiac systolic function, with no significant difference between the two routes. Vomiting occurred in half of the IN group (4/8) and in all cats of the IM group (8/8), with a significantly lower incidence in the IN group ( P = 0.046). Conclusions and relevance IN delivery of-DEX provided comparable sedation, increased tolerance to mechanical nociception and muscle relaxation effects while causing fewer adverse effects than IM-DEX. Both routes similarly reduced cardiac contractile function. Thus, IN-DEX at a dose of 10 μg/kg is a viable alternative to IM-DEX for sedation in healthy cats.