Comparison of behavioral and clinical effects of intravenous amitraz or romifidine administration in horses

Abstract

Clinical and behavioral effects of intravenous injection of romifidine (60mcg/kg) or amitraz (0.4mg/kg) were compared in six horses, over 120 min. Romifidine caused head ptosis (HP), reduced respiratory rate (RR) and ileo-cecal sphincter activity (IC) until 120 minutes; produced posture changes (PC) until 90 minutes, upper eyelid drop (ED) and sedation (SD) until 60 minutes, intestinal motion (IM) reduction and lower lip drop (LD) until 45 minutes. Amitraz reduced heart rate (HR), RR, IM and IC, and promoted HP, ED, LD, penis drop (PD) and sedation with posture changes until 120min. At 90min amitraz produced HP and ED more intensively than romifidine. The LD was similar between 45 and 60 minutes. Romifidine produced intense sedation at 10min while amitraz sedation was more significant between 90 and 120 minutes. It is concluded that both romifidine and amitraz can produce strong sedation until 60 and 120 minutes, respectively. Though amitraz sedation and posture changes had a later onset related to romifidine, these effects lasted longer.Keywords: horse, amitraz, romifidine, sedation (corresponding address) RESUMO Compararam-se os efeitos sedativos e clínicos em seis eqüinos tratados com romifidina (60mcg/kg) ou amitraz (0,4mg/kg), pela via intravenosa, durante 120 minutos. A romifidina promoveu ptose da cabeça (PC), reduziu a freqüência respiratória (FR) e o movimento da válvula íleo-cecal (MC) durante 120 minutos, provocou alteração postural (AP) por 90 minutos, induziu ptose palpebral (PP) e sedação (SD) por 60 minutos, diminuiu a motilidade intestinal (MI) e causou ptose labial (PL) durante 45 minutos. O amitraz reduziu a freqüência cardíaca (FR), FR, MI e MC e provocou PC, PP, PL

Echocardiographic Assessment After Intravenous Amitraz or Xylazine Injection in Cats

“…In one study, sedation, loss of reflexes, mydriasis, bradycardia, bradyarrhythmias and bradypnea were effectively reversed with 0.2 mg/kg of atipamezole, an a 2 -adrenergic antagonist with high affinity (aNDraDe et al 2006). There are few studies with amitraz diluted in lipid vehicle in large animals (aLMeIDa et at., 2004;MeNDes et al, 2007;LINarDI et al, 2008) and the only report in small animals using this vehicle was made by FarIas et al (2005), who tested a dosage of 1.0 mg/kg.…”

“…amitraz is an insecticide used in veterinary medicine as an acaricide and tickicide (sHarMa & Dabas, 1993), whose mechanism of action are similar to other a 2 -adrenoreceptors agonists (HsU & KaKUK, 1984;QUeIroZ-NeTo et al, 2000;FarIas et al, 2005). sedation, analgesia and cardiovascular depression similar to the a 2adrenoreceptors agonists have been described in several species after amitraz intravenous injection (QUeIroZ-NeTo et al, 2000;aLMeIDa et al, 2004;FarIas et al, 2005;MeNDes et al, 2007;LINarDI et al, 2008).…”

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

“…-Pelotas, RS-Brazil) emulsion (0.1mg/kg or 0.4mg/kg) was injected in the external jugular vein. Amitraz emulsion was prepared as described by Farias 21 and the applied doses were based on previous studies with this emulsion on horses 22,23 . Initially, HP was evaluated at ten minute intervals (T10, T20 e T30), followed by fifteen minute intervals (T45 e T60) for the first hour and then at thirty minute intervals (T90, T120, T150 e T180) until the third observation hour.…”