Romifidine is an α2 adrenergic receptor agonist. Romifidine shows sedation effects in vivo[1][2].
Romifidine (80 μg/kg; i.v. once) produces sedative effects with significantly greater drooping during the 45-90 min time period in welsh mountain ponies[1].
Romifidine (40, 80 and 120 mg/kg; i.v. at seven-day intervals) shows a shallower and shorter-lived sedation than with detomidine in horses[2].
[1]. England GC, et al. A comparison of the sedative effects of three alpha 2-adrenoceptor agonists (romifidine, detomidine and xylazine) in the horse. J Vet Pharmacol Ther. 1992 Jun;15(2):194-201.
[2]. Hamm D, et al. Sedative and analgesic effects of detomidine and romifidine in horses. Vet Rec. 1995 Apr 1;136(13):324-7.