Romifidine hydrochloride is an α2 adrenergic receptor agonist. Romifidine hydrochloride shows sedation effects in vivo[2].In Vivo:Romifidine hydrochloride (80 μg/kg; i.v. once) produces sedative effects with significantly greater drooping during the 45-90 min time period in welsh mountain ponies.Romifidine hydrochloride (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].