Efeitos antinociceptivos, cardiorrespiratórios e gastrointestinais da detomidina associada ou não à metadona em equinos
Carregando...
Data
2011-02-25
Autores
Pignaton, Wangles [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Apesar de doses relativamente elevadas de opioides produzirem maior intensidade de efeito analgésico, tais doses também estão associadas a efeitos adversos que podem limitar seu emprego em equinos. No presente estudo, hipotetizou-se que uma dose baixa de metadona (0,2 mg/kg), a qual não produz analgesia consistente quando administrada isoladamente em modelos de dor experimental, potencializaria a analgesia induzida pela detomidina, sem resultar em efeitos adversos como excitação/depressão cardiorrespiratória importante ou potencializar a hipomotilidade intestinal induzida pelo agonista α2-adrenérgico. Seis equinos (415 ± 20 kg) receberam dois tratamentos intravenosos com intervalo mínimo de uma semana em um delineamento aleatorizado duplo-cego: 0,01 mg/kg de detomidina administrada isoladamente (tratamento DET) ou em associação a 0,2 mg/kg de metadona (tratamento DET/MET). A analgesia foi avaliada através dos limiares nociceptivos térmico (LNT) e elétrico (LNE). O LNT consistiu no tempo para retirada do membro torácico em resposta à lâmpada de projeção de calor aplicada sobre a banda coronária. O LNE consistiu na voltagem (aplicada via eletrodos sobre a banda coronária) mais elevada capaz de induzir a retirada do membro torácico. A sedação foi avaliada pela distância queixo-solo e pelo interesse por alimento (feno de alfafa). A analgesia, sedação e parâmetros cardiorrespiratórios (eletrocardiografia, pressão arterial e gasometria arterial) foram avaliados antes e durante 120 min após os a administração dos tratamentos. Os escores de auscultação intestinal foram determinados durante 12 horas após a administração dos tratamentos. Tanto o LNE como o LNT se elevaram significativamente em relação aos valores basais durante 15 min após a DET. No tratamento DET/MET, a administração dos fármacos resultou em elevação significativamente...
Although relativelly high doses of opioids result in greater analgesic effect, these doses also cause adverse effects that may limit its clinical usefullness in horses. In the present study it was hipothesized that a dose of methadone that does not induce a consistent analgesic effect when administered alone (0.2 mg/kg) in experimental pain models would potentialize detomidine’s analgesic effect without resulting in adverse side effects such as excitation / important cardiorespiratory depression or potentialization of the intestinal hypomotility induced by the alpha-2 agonist. A total of six horses (415 ± 20 kg) received 2 intravenous treatments in a randomized double-blinded study design: 0.01 mg/kg of detomidine administered alone (DET treatment) or combined with 0.2 mg/kg of methadone (DET/MET treatment). The analgesia was evaluated by assessing the thermal (TNT) and electrical nociceptive thresholds (ENT). The TNT was assessed by measuring time for limb withdrawal (thoracic limb) in response to a heat projection lamp applied to the coronary band. The ENT was recorded as the highest voltage (applied via electrodes placed in the coronary band of the thoracic limb) that induced limb withdrawal. Sedation was assessed by the chin-to-floor distance and by the interest for food (alfalfa hay). The nociceptive testing, sedation and cardiorespiratory data (electrocardiography, direct arterial pressures, and arterial blood gases) were recorded before and during 120 minutes after drug injection. The intestinal auscultation scores were recorded for 12 hours after treatment administration.Both the ENT and the TNT significantly increased from baseline during 15 minutes after DET. In the DET/MET treatment, drug injection resulted in significantly greater and more prolonged (30 minutes increases in ENT and TNT in comparison to the DET treatment. The chin-to-floor distance was significantly... (Complete abstract click electronic access below)
Although relativelly high doses of opioids result in greater analgesic effect, these doses also cause adverse effects that may limit its clinical usefullness in horses. In the present study it was hipothesized that a dose of methadone that does not induce a consistent analgesic effect when administered alone (0.2 mg/kg) in experimental pain models would potentialize detomidine’s analgesic effect without resulting in adverse side effects such as excitation / important cardiorespiratory depression or potentialization of the intestinal hypomotility induced by the alpha-2 agonist. A total of six horses (415 ± 20 kg) received 2 intravenous treatments in a randomized double-blinded study design: 0.01 mg/kg of detomidine administered alone (DET treatment) or combined with 0.2 mg/kg of methadone (DET/MET treatment). The analgesia was evaluated by assessing the thermal (TNT) and electrical nociceptive thresholds (ENT). The TNT was assessed by measuring time for limb withdrawal (thoracic limb) in response to a heat projection lamp applied to the coronary band. The ENT was recorded as the highest voltage (applied via electrodes placed in the coronary band of the thoracic limb) that induced limb withdrawal. Sedation was assessed by the chin-to-floor distance and by the interest for food (alfalfa hay). The nociceptive testing, sedation and cardiorespiratory data (electrocardiography, direct arterial pressures, and arterial blood gases) were recorded before and during 120 minutes after drug injection. The intestinal auscultation scores were recorded for 12 hours after treatment administration.Both the ENT and the TNT significantly increased from baseline during 15 minutes after DET. In the DET/MET treatment, drug injection resulted in significantly greater and more prolonged (30 minutes increases in ENT and TNT in comparison to the DET treatment. The chin-to-floor distance was significantly... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Anestesicos - Efeito fisiologico, Equino - Efeito das drogas, Analgesia, Methadone, Opioids
Como citar
PIGNATON, Wangles. Efeitos antinociceptivos, cardiorrespiratórios e gastrointestinais da detomidina associada ou não à metadona em equinos. 2011. 56 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, 2011.