Efeitos sedativos e cardiorrespiratórios da metadona em cães: estudo comparativo com a morfina
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Data
2007-07-03
Autores
Maiante, Ariádine Augusta [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Poucos estudos vem sendo reportados com uso da metadona em pequenos animais. Neste estudo os efeitos sedativos, cardiorrespiratórios e comportamentais da metadona e da morfina foram comparados em seis cães conscientes sem raça definida. No dia do estudo, os cães (16,4 ± 2,8 kg) foram instrumentados para monitorização hemodinâmica com isoflurano, e após 60 minutos do término da anestesia inalatória foi iniciada a coleta de dados. Morfina, (1 mg/kg) ou duas doses de metadona (0,5 mg/kg [MET0,5] ou 1,0 mg/kg [MET1]) foram administradas pela via intravenosa durante um minuto em um delineamento aleatório cruzado, aguardando-se um intervalo mínimo de 1 semana entre cada tratamento. As variáveis foram registradas antes (basal) e por 120 minutos após a administração dos fármacos, adotando como nível de significância p< 0,05. Devido a um marcado aumento (356%) do índice de resistência vascular sistêmica (dinas•seg/cm5/m2) após cinco minutos da administração de morfina, um animal apresentou resultado positivo para o teste de detecção de outlier (teste de Grubb) não sendo incluso na análise estatística das variáveis hemodinâmicas. Não houve diferença entre os tratamentos nos parâmetros basais. A morfina reduziu a FC (bpm), comparado aos valores basais, dos 30-120 minutos (valores mínimos: 86±11 aos 120 minutos), contudo o IC (L/min/m2) reduziu-se aos 120 minutos (4,40±1,07). Comparado com a com a morfina, MET 1 causou maior e mais prolongada redução destes parâmetros (valores mínimos: 63±16 e 2,95±1,06 para FC e IC respectivamente); reducões intermediárias foram observadas com MET 0,5 (valores mínimos: 78±9 e 3,72±0,81 para FC e IC respectivamente). O IRVS aumentou apenas após a administração de metadona, sendo a MET 1 produziu maior aumento que MET 0,5 (valores máximos: 3192±882 e 2178±588 para MET 1 e MET 0,5 respectivamente) A morfina aumento a POAP (mmHg) após cinco minutos (12±4) enquanto...
Few controlled studies have been reported on the use methadone in small animals. In this study, the cardio-respiratory effects of methadone and morphine were compared in six conscious mongrel dogs. On the study day, the dogs (16.4±2.8 kg) were instrumented for hemodynamic monitoring under isoflurane anesthesia, allowing at least 60 min from termination of inhalant anesthesia before commencing data collection. Morphine (1 mg/kg) or two different doses of methadone (0.5 mg/kg [MET0.5] or 1.0 mg/kg [MET1]) were administered intravenously over 1 min in a randomized crossover design (minimum washout period: 1-week). Variables were recorded before (baseline), and for 120 min after drug administration. A split plot design model compared cardiopulmonary data (mean±SD) (p<0.05). Because of marked increases in SVRI (dynes•seg/cm5/m2) after morphine (353% increase from baseline at 5 min, one animal tested positive for an outlier detection test (Grubbs’ test) and was not included in the statistical analysis for hemodynamic data. Baseline variables did not differ among treatments. Morphine reduced HR (beats/min) compared to baseline from 30-120 min (lowest value: 8611 at 120 min), while CI (L/min/m2) was reduced from baseline at 120 min (4.40±1.07). Compared to morphine, MET1 caused greater and more prolonged reductions in these parameters (lowest values: 63±16 and 2.95±1.06 for HR and CI, respectively), while intermediate reductions in HR and CI were observed after MET0.5 (lowest values: 78±9 and 3.72±0.81 for HR and CI, respectively). The SVRI was increased after methadone only, with MET1 producing a higher SVRI than MET0.5 (highest values: 3192±882 and 2178±588 for MET1 and MET0.5, respectively). Morphine increased PAOP (mm Hg) from baseline at 5 min (12±4), while this parameter remained increased from baseline for 90 and 120 min after MET0.5 (maximum increase: 163) and MET1.0 (maximum increase: 173), respectively.
Few controlled studies have been reported on the use methadone in small animals. In this study, the cardio-respiratory effects of methadone and morphine were compared in six conscious mongrel dogs. On the study day, the dogs (16.4±2.8 kg) were instrumented for hemodynamic monitoring under isoflurane anesthesia, allowing at least 60 min from termination of inhalant anesthesia before commencing data collection. Morphine (1 mg/kg) or two different doses of methadone (0.5 mg/kg [MET0.5] or 1.0 mg/kg [MET1]) were administered intravenously over 1 min in a randomized crossover design (minimum washout period: 1-week). Variables were recorded before (baseline), and for 120 min after drug administration. A split plot design model compared cardiopulmonary data (mean±SD) (p<0.05). Because of marked increases in SVRI (dynes•seg/cm5/m2) after morphine (353% increase from baseline at 5 min, one animal tested positive for an outlier detection test (Grubbs’ test) and was not included in the statistical analysis for hemodynamic data. Baseline variables did not differ among treatments. Morphine reduced HR (beats/min) compared to baseline from 30-120 min (lowest value: 8611 at 120 min), while CI (L/min/m2) was reduced from baseline at 120 min (4.40±1.07). Compared to morphine, MET1 caused greater and more prolonged reductions in these parameters (lowest values: 63±16 and 2.95±1.06 for HR and CI, respectively), while intermediate reductions in HR and CI were observed after MET0.5 (lowest values: 78±9 and 3.72±0.81 for HR and CI, respectively). The SVRI was increased after methadone only, with MET1 producing a higher SVRI than MET0.5 (highest values: 3192±882 and 2178±588 for MET1 and MET0.5, respectively). Morphine increased PAOP (mm Hg) from baseline at 5 min (12±4), while this parameter remained increased from baseline for 90 and 120 min after MET0.5 (maximum increase: 163) and MET1.0 (maximum increase: 173), respectively.
Descrição
Palavras-chave
Cão - Cirurgia, Sedativos - Efeitos fisiológicos - Estudos experimentais
Como citar
MAIANTE, Ariádine Augusta. Efeitos sedativos e cardiorrespiratórios da metadona em cães: estudo comparativo com a morfina. 2007. 79 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Medicina Veterinária e Zootecnia, 2007.