Sedative action of the α₂‐agonist medetomidine in cats

Abstract

Medetomidine, a novel alpha 2-agonist drug intended for small animal sedation, was injected intramuscularly at dose rates of 0.02, 0.06 and 0.18 mg/kg. Xylazine (3.0 mg/kg) and saline were used for comparison. The five treatments were tested in a Latin square design in five cats. Treatments differed significantly in three-way analysis of variance, medetomidine inducing an increase in drowsiness with a corresponding decrease in both aroused waking and sleep determined by polygraphical criteria. The duration of effect was dose-dependent. The effect of 0.18 mg/kg medetomidine was comparable to 3.0 mg/kg of xylazine. The drugs also induced bradycardia.

Evaluation of the clinical efficacy and safety of dexmedetomidine or medetomidine in cats and their reversal with atipamezole

“…The potency and duration of the sedative and analgesic effects of DEX or MED observed in the present study are consistent with previous reports (Stenberg et al. 1987; Vähä‐Vahe 1989; Ansah et al.…”

Cardiovascular effects of a high dose of romifidine in propofol-anesthetized cats

“…9,24,25 Furthermore, analysis of our results suggests that there may be a maximal or ceiling effect on car-diovascular changes similar to that reported in dogs following IV administration of romifidine. 9,24,25 Furthermore, analysis of our results suggests that there may be a maximal or ceiling effect on car-diovascular changes similar to that reported in dogs following IV administration of romifidine.…”

“…[11][12][13] Additionally, increases in cardiac preload caused by bradycardia or α 2 -agonist-induced venoconstriction, as suggested by an increase in central venous pressure, would be expected to increase cardiac inotropy via the Starling mechanism. 10 Analysis of results of the study reported here and results of other studies 6,9,10,[23][24][25] in dogs, cats, and horses suggests that maximum cardiovascular effects of currently available α 2 -agonists can be reached at clinically relevant dosages and before maximum sedative effects are observed. Similar conclusions have been reached by other investigators who have conducted research on dose-response characteristics of medetomidine in dogs and cats.…”

The clinical effectiveness of atipamezole as a medetomidine antagonist in the dog

“…Bradycardia is a prominent medetomidineinduced effect as previously shown in several animal species (Stenberg et al, 1987;Virtanen et al, 1988;Vainio et al, 1989). Atipamezole was also able to reverse this effect in a doserelated manner.…”