Comparison of intranasal atipamezole by atomization or drops with intramuscular injection for reversing sedative effects of medetomidine in healthy dogs.

OBJECTIVE

To determine and compare the efficacy of intranasal (IN) atomization, IN drops, and IM injection of atipamezole for reversal of medetomidine-induced sedation in healthy dogs.

DESIGN

Prospective, randomized, blinded study.

SETTING

University teaching hospital.

ANIMALS: Forty mixed-breed, shelter-owned dogs with an average weight of 29.9 ± 5.6 kg (mean ± SD) that required sedation for minor diagnostic or therapeutic procedures.

INTERVENTIONS: Atipamezole was administered by a dog handler at 200 µg/kg via IN atomization (ATI-INA, n = 10), IN drops (ATI-IND, n = 10), or IM injection (ATI-IM, n = 10) 20 minutes following medetomidine administration (40 µg/kg). A control group (n = 10) received no atipamezole.

MEASUREMENTS AND MAIN

RESULTS

Ease of atipamezole administration was evaluated. Sedation score, heart rate (HR), respiratory rate (RR), and blood pressure (BP) were recorded pre-medetomidine administration (T0), pre-atipamezole administration (T20), and at multiple intervals following atipamezole administration. ATI-IM resulted in the fastest recovery, followed by ATI-INA, with ATI-IND being the slowest. The adverse cardiovascular impacts of medetomidine were not completely mitigated. ATI-IM showed initial HR restoration followed by a decline. HR in both IN groups showed a slower increase compared to ATI-IM, but no subsequent decline was observed. ATI-IM resulted in a transient decrease in BP, though dogs remained normotensive. A gradual reduction in BP was noted in the IN groups. At T50, RR of all atipamezole groups differed from control, and a significant increase in RR was observed in ATI-IM dogs compared to pre-atipamezole value. No adverse effects were observed.

CONCLUSIONS

All routes for atipamezole administration effectively reversed medetomidine-induced sedation, with ATI-IM being fastest. IN routes were easy for the dog handler to administer, making them viable alternatives in cases of accidental drug exposure, particularly outside a hospital setting.