Comparison of intramuscular medetomidine versus medetomidine-vatinoxan sedation in bearded dragons (Pogona vitticeps)

Objective

To assess sedation following intramuscular (IM) administration of medetomidine versus medetomidine–vatinoxan in bearded dragons.

Study design

Prospective, randomized, experimental, crossover study.

Animals

A group of 10 (five males and five females) bearded dragons (mean mass ± standard deviation 172 ± 28 g).

Methods

All animals were administered both medetomidine (0.2 mg kg^–1) (MED) and medetomidine (0.2 mg kg^–1)-vatinoxan (4 mg kg^–1) (MED-VAT) IM, with a 14–16 day washout period between treatments. Sedation was assessed using an adapted version of a sedation scale for bearded dragons (scale range 0–12) before (T0), and every 5 minutes from 10 to 45 minutes after treatment administration (T10–T45). Sedation scores were compared: 1) between time points (within treatments) using a Friedman test and Dunn’s post hoc test; and 2) between treatments at each time point using a Wilcoxon paired test. Heart rate and respiratory rate (f_R) were analyzed descriptively. At T45, atipamezole was administered IM.

Results

Compared with T0, sedation scores were significantly higher at most time points for both treatments. Highest median (range) scores occurred at T30 for MED [T0, 0 (0–0); T30, 2.5 (1–5); p = 0.0001] and at T35 and T40 for MED-VAT [T0, 0 (0–0); T35, 2 (1–5); p = 0.002; T40, 2 (1–5); p = 0.001]. No significant differences in sedation scores were identified between treatments at any time point. The two protocols caused bradycardia and reduction in f_R. All animals were active and ate 1 hour after reversal administration.

Conclusions and clinical relevance

Both medetomidine and medetomidine–vatinoxan caused similar mild sedation in bearded dragons (median < 3/12). Inclusion of vatinoxan did not enhance sedation in this species.