Alpha2 adrenoceptor agonists in the horse—Areview

England, G. C. W.; Clarke, K. W.

doi:10.1016/s0007-1935(96)80118-7

Cited by 177 publications

(198 citation statements)

References 47 publications

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“…An increase in [Glu] B has been described in the horse after administration of single doses of different alpha 2 -adrenergic agonists (England and Clarke, 1996) and during detomidine CRI combined with buprenorphine (van Dijk et al, 2003). However, to our knowledge this is the first time effects on [Glu] B were studied during CRIs of alpha 2 -adrenergic agonists as sole agents in horses.…”

Section: Discussionmentioning

confidence: 88%

“…Concerns regarding alpha 2 -adrenergic agonists mainly reflect their cardiovascular (CV) effects (England and Clarke, 1996;Murrell and Hellebrekers, 2005;Tan and Ho, 2010), and many studies have been designed to examine the CV effects of alpha 2 -adrenergic agonist CRIs in horses (Bettschart-Wolfensberger et al, 1999;Ringer et al, 2013a). However, the use of alpha 2 -adrenergic agonists is also associated with other side effects that might be less obvious, but may have important consequences, especially in critically ill patients.…”

Section: Introductionmentioning

confidence: 99%

“…For example, hyperglycaemia is associated with worse outcomes in proportion to the elevations in blood glucose concentration ([Glu] B ) in human medicine (Klonoff, 2011). Hyperglycaemia is also associated with diuresis, which has been described following single doses of alpha 2 -adrenergic agonists in horses (England and Clarke, 1996) and other species (Ambrisko and Hikasa, 2002;Kanda and Hikasa, 2008;Talukder and Hikasa, 2009;Murahata and Hikasa, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Blood glucose, acid–base and electrolyte changes during loading doses of alpha2-adrenergic agonists followed by constant rate infusions in horses

Ringer¹,

Schwarzwald²,

Portier³

et al. 2013

The Veterinary Journal

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The aim of the present study was to investigate changes in blood glucose concentration ([Glu]B), acid-base status and electrolyte concentrations during constant rate infusions (CRI) of two alpha2-adrenergic agonists in seven horses treated in a blinded, randomised, crossover design with xylazine or romifidine. An intravenous (IV) bolus of xylazine (1mg/kg) or romifidine (80g/kg) was administered followed by an IV CRI of xylazine (0.69mg/kg/h) or romifidine (30g/kg/h) for 2h. Blood samples were collected from the pulmonary artery before and after loading doses, during the CRI, and for 1h after discontinuing drugs. Blood glucose, base excess (BE), pH, partial pressure of carbon dioxide (Pv¯CO2), strong ion difference (SIDest) and bicarbonate concentration ( [Formula: see text] ) increased significantly during the CRI with both alpha2-adrenergic agonists. Chloride concentration ([Cl-]B) and anion-gap (AG) decreased significantly compared to baseline. The decrease in sodium concentration ([Na+]B) was only significant with xylazine. From 1h after starting the CRI onwards, [Glu]B was significantly higher with romifidine compared to xylazine. Except [Glu]B, SIDest, and Pv¯CO2, all variables returned to normal values 1h after discontinuing xylazine. After stopping romifidine, all variables except pH remained altered for at least 1h. It was concluded that loading doses of alpha2-adrenergic agonists followed by CRIs produce [Glu]B, acid-base and electrolyte changes. The clinical significance of the reported changes remains to be investigated and absolute values should be interpreted with caution, as fluid boli were used for cardiac output measurements, but may become important during prolonged infusion and in critically ill patients. a b s t r a c tThe aim of the present study was to investigate changes in blood glucose concentration ([Glu] B ), acidbase status and electrolyte concentrations during constant rate infusions (CRI) of two alpha 2 -adrenergic agonists in seven horses treated in a blinded, randomised, crossover design with xylazine or romifidine.An intravenous (IV) bolus of xylazine (1 mg/kg) or romifidine (80 lg/kg) was administered followed by an IV CRI of xylazine (0.69 mg/kg/h) or romifidine (30 lg/kg/h) for 2 h. Blood samples were collected from the pulmonary artery before and after loading doses, during the CRI, and for 1 h after discontinuing drugs. Blood glucose, base excess (BE), pH, partial pressure of carbon dioxide (P vCO 2 ), strong ion difference (SID est ) and bicarbonate concentration (½HCO It was concluded that loading doses of alpha 2 -adrenergic agonists followed by CRIs produce [Glu] B , acid-base and electrolyte changes. The clinical significance of the reported changes remains to be investigated and absolute values should be interpreted with caution, as fluid boli were used for cardiac output measurements, but may become important during prolonged infusion and in critically ill patients.

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Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Blood glucose, acid–base and electrolyte changes during loading doses of alpha2-adrenergic agonists followed by constant rate infusions in horses

Ringer¹,

Schwarzwald²,

Portier³

et al. 2013

The Veterinary Journal

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“…When administered as 78 a constant rate intravenous infusion (CRI) as a component of partial intravenous anaesthesia 79 (PIVA), it reduces the minimum alveolar concentration (MAC) of isoflurane in horses (Neges et al, 80 2003) and improves the quality of recovery (Ringer et al, 2007). Medetomidine, like other α 2 81 agonists, causes cardiopulmonary effects, including reduction in cardiac output (Qt), biphasic 82 changes in arterial blood pressure (ABP), bradycardia and arrhythmias (England and Clarke, 1996 Horses were fasted for 10-12 h before anaesthesia for elective laryngeal surgery; access to 107 water was not restricted. Flunixin meglumine (1.1 mg/kg IV; Flunixin Injection, Norbrook 108 Laboratories) was infused through a 14 G x 13 cm jugular catheter (Milacath Extended Use, Mila).…”

mentioning

confidence: 99%

Effect of low inspired oxygen fraction on respiratory indices in mechanically ventilated horses anaesthetised with isoflurane and medetomidine constant rate infusion

Taylor

Seymour

2016

The Veterinary Journal

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“…Esta manifestação foi descrita como um dos efeitos menos importantes das drogas agonistas a 2 -adrenérgicas (England & Clarke 1996), grupo do qual, comprovadamente, o amitraz faz parte (Sellers et al 1984, Roberts & Argenzio 1986, Hovda & McManus 1993, Duncan 1993, Pass & Mogg 1995, Hugnet & Cadoré 1995, Hugnet et al 1996, Harkins et al 1997, Queiroz-Neto et al 1998. Esta alteração tem sido associada à utilização de drogas do grupo das fenotiazinas, que causam bloqueio dos receptores a 1 (Speirs 1999).…”

Section: Aspectos Toxicológicosunclassified

Intoxicações natural e experimental por amitraz em eqüídeos: aspectos clínicos

et al. 2003

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A administração oral e a aspersão com amitraz reproduziram experimentalmente em 17eqüinos e um asinino um quadro de intoxicação muito similar a outro que vinha ocorrendo em cavalos no Estado do Rio de Janeiro. O início dos sintomas após a administração oral variou entre 15min. e 2h05min., na aplicação por aspersão variou entre 6h28min. e 8h38min. A evolução nos casos de administração oral foi de 4 a 9 dias, nos de aspersão de 5 a 6 dias. Somente morreram animais que receberam a administração oral. Um animal aspergido com o amitraz foi sacrificado. Por via oral foram usadas dosagens de 5,5 mg/kg (uma administração), 5,8 mg/kg (duas administrações) e num terceiro animal, doses que variaram entre 7,2 e 36,4 mg/kg (cinco administrações). Nas aplicações por aspersão, a intoxicação foi reproduzida com soluções nas concentrações de 0,1 e 0,2%. Com relação ao sistema nervoso, os principais sinais observados foram apatia, sonolência, ptoses palpebral e auricular, dificuldade de apreensão, mastigação e deglutição do alimento, arrastar das pinças dos cascos no solo, exposição do pênis, sensibilidade cutânea diminuída/ausente, instabilidade em estação, abdução dos membros, cabeça baixa, incoordenação, bocejos, flacidez labial, exposição da língua, cruzamento dos membros ao caminhar, resposta postural diminuída após cruzar e abduzir os membros, reflexos do lábio superior, palatal, lingual, de deglutição e flexor diminuídos/ausentes, reflexos auricular, palpebral e de ameaça diminuídos e resposta ambulatória diminuída ao teste de girar em círculo de pequeno raio. No que se refere ao sistema digestivo, foram evidenciados, principalmente, hipomotilidade/atonia intestinal, edema dos lábios, distensão abdominal, deitar e levantar com freqüência, rolar no solo, olhar para o flanco, gemer e impactação do intestino grosso. Observaram-se ainda taquicardia, aumento do tempo de preenchimento capilar e mucosas congestas, estridor, taquipnéia, dispnéia, secreção nasal, bradipnéia e respiração abdominal. Todos os três casos naturais ocorreram após aspersão do amitraz. Os primeiros sintomas foram observados 2 e 3 dias após o banho. A evolução foi de 6, 7 e 17 dias. Um animal manifestou a maioria dos sinais referentes ao sistema nervoso observados nos experimentos, com exceção dos sinais de cruzamento dos membros ao caminhar, bocejos, lábios flácidos e exposição do pênis. Outro animal, intoxicado espontaneamente, manifestou somente sintomas digestivos como rolar, ''patear'', hipomotilidade/atonia intestinal e impactação do intestino grosso. Um terceiro animal, inicialmente manifestou sintomas digestivos caracterizados por patear, rolar, atonia intestinal e impactação do intestino grosso, com conseqüente desenvolvimento de laminite; na fase final exibiu acentuada sintomatologia nervosa mostrando compressão da cabeça contra obstáculos, incoordenação motora com cruzamento dos membros ao caminhar e relutância em se movimentar. Baseados no quadro clínico observado, são sugeridos possíveis locais de lesão no sistema nervoso.

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Alpha2 adrenoceptor agonists in the horse—Areview

Cited by 177 publications

References 47 publications

Blood glucose, acid–base and electrolyte changes during loading doses of alpha2-adrenergic agonists followed by constant rate infusions in horses

Blood glucose, acid–base and electrolyte changes during loading doses of alpha2-adrenergic agonists followed by constant rate infusions in horses

Effect of low inspired oxygen fraction on respiratory indices in mechanically ventilated horses anaesthetised with isoflurane and medetomidine constant rate infusion

Intoxicações natural e experimental por amitraz em eqüídeos: aspectos clínicos

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