Comparison of the sedative effects of intranasal or intramuscular dexmedetomidine at low doses in healthy dogs: a randomized clinical trial

Abstract

Objective: To compare the sedative effects of dexmedetomidine administered either intranasally or intramuscularly to healthy dogs.

Study design: Prospective, randomized, blinded, clinical trial.

Animals: A group of 16 client-owned healthy dogs.

Methods: Dogs were randomly allocated to one of two groups that were administered dexmedetomidine 5 μg kg^-1 via either the intranasal route (IN_Dex), through a mucosal atomization device in one nostril, or the intramuscular route (IM_Dex), into the epaxial muscles. Ease of intranasal administration, sedation score, onset of sedation, cardiopulmonary variables, mechanical nociceptive thresholds (MNTs) and response to venous catheterization were recorded at 0 (baseline), 5, 10, 15, 20, 25, 30, 35, 40 and 45 minutes, following drug administration. Data were compared with the one-way anova, Mann-Whitney U test, and chi-square test, where appropriate.

Results: Groups were not different for age, sex, weight, body condition score or temperament. Sedation scores, MNTs and response to intravenous catheter placement were not different when dexmedetomidine was administered by either route (p = 0.691; p = 0.630 and p = 0.435, respectively). Onset of sedation was not different between groups IN_Dex and IM_Dex reaching a score of 4.2 ± 0.9 and 5.5 ± 1.2 at 9 ± 5 and 8 ± 4 minutes, respectively (p = 0.467). The highest sedation score was achieved at 30 and 35 minutes and sedation scores were 9.7 ± 2.0 and 9.5 ± 2.3 in groups IN_Dex and IM_Dex, respectively (p = 0.799). Respiratory rate was higher in group IN_Dex (p = 0.014), while there were no differences between routes in heart rate (p = 0.275), systolic (p = 0.957), diastolic (p = 0.837) or mean arterial pressure (p = 0.921).

Conclusions and clinical relevance: Intranasal administration of dexmedetomidine at 5 μg kg^-1 provides effective sedation in healthy dogs.

Keywords: dexmedetomidine; dog; intramuscular; intranasal; nasal atomizer; sedation.