Intranasal administration and intramuscular administration of medetomidine are effective for sedation and may increase cardiac size in cats.

Abstract

Objective: This study aimed to compare the effects of intranasal (IN) and IM administration of medetomidine on cardiac size and sedation variables in cats.

Methods: This study included 14 male tabby cats, aged 1 to 3 years, with American Society of Anesthesiologists status of 1 to 2. The cats were randomly assigned to 2 groups (IN and IM; n = 7 cats/group) and received 0.08 mg/kg of medetomidine. Radiographic and anesthesia parameters were recorded at multiple time points.

Results: No significant differences were observed between the groups in terms of cardiac size, except for the ventrodorsal cardiothoracic ratio, which showed a significant increase from baseline at several time points. Heart rate, respiratory rate, rectal temperature, and systolic and diastolic blood pressure showed no significant intergroup differences. Peripheral arterial oxygen saturation was significantly lower in the IM group (90 [85 to 93]) compared to the IN group (95 [92 to 100). The onset of clinical sedation was significantly faster in the IM group (3.85 ± 1.21 minutes) than in the IN group (9.85 ± 4.98 minutes). Lateral recumbency was achieved significantly earlier in the IM group (7.28 ± 1.79 minutes) compared to the IN group (12.42 ± 4.79 minutes).

Conclusions: Both IN and IM administration of medetomidine in cats resulted in increased ventrodorsal cardiothoracic ratios compared to baseline, with no significant differences between groups for this parameter.

Clinical relevance: Both IN and IM administration of medetomidine were well tolerated and effective for sedation in cats, with comparable safety profiles.