Sedative and analgesic effects of detomidine and romifidine in horses

Abstract

In a double blind study, eight horses were treated intravenously at seven-day intervals with detomidine at doses of 10, 20 and 40 micrograms/kg, or with romifidine at doses of 40, 80 and 120 micrograms/kg, or with a placebo solution. Their sedative and analgesic effects were evaluated by objective measurements and by a clinician at 15-minute intervals for three hours and the horses' instability in stocks, locomotor ataxia and heart rate were recorded simultaneously. The administration of both drugs at all doses resulted in sedation. The sedation achieved with romifidine was significantly shallower and shorter-lived than with detomidine at the recommended doses (P < 0.05). The results obtained with the highest dose of romifidine were in some cases significantly inferior and shorter-lived than those obtained with the medium dose (P < 0.05). Detomidine at the 10 micrograms/kg dose was similar in its effects to the two highest doses of romifidine. At all doses detomidine had analgesic properties against the effects of electrical pain stimulation at the withers, the coronary bands on the front and hind legs, and in the perianal region, which were dose-dependent in depth and duration, whereas romifidine was devoid of any analgesic effect. Instability and ataxia were more pronounced with detomidine than with romifidine but the effects were only slight to moderate and not regarded as a hindrance to procedures for which sedation is needed. Bradycardia was evident with both drugs at all doses; its severity and duration was related to the sedative properties of the drugs and was dose related. No other side effects were observed.

Comparação dos efeitos da romifidina e de uma emulsão de amitraz na sedação e na atividade locomotora espontânea de eqüinos

“…Thus, a clinical comparison between amitraz and romifidine, which is a potent alpha-2 agonist 24,25 , is proposed as an efficient method to establish possibilities of using amitraz as an intense and long lasting sedative for horses. The comparison between the amitraz 0.1 and 0.4mg/kg shows stronger effects at the higher dose.…”

Clinical course, heart rate and pulmonal functions during thoracoscopy in the standing horse – part 1: clinical, heart rate and blood gases

“…Die gesamten Untersuchungen fanden aufgrund der zirkadianen Schwankungen der Atmungsmechanik (Stadler 1983, Stadler et al 1985 Keller (1989), England et al (1992) Keller und Genzow (1994), Hamm et al (1995) sowie Freeman und England (1999). Nach der AppliAbb.…”

Sedative and antinociceptive effects of romifidine and xylazine in Thoroughbred mares

“…However, studies regarding the antinociceptive effect of romifidine are scarce. Hamm et al (1995) studied the sedative and antinociceptive effects of detomidine and of romifidine in horses and concluded that the two agents cause sedation, but that only detomidine has analgesic properties. Therefore, further studies are needed to clarify whether or not romifidine possesses antinociceptive effects, since it shows a greater selectivity for the α 2 receptor than does xylazine (Slater, 1993).…”