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Artigo Produção Nacional Revisado por pares
BIBTEX RIS

Electrocardiographic evaluation of the degree of sedation and the isolated use of methadone in healthy dogs

2013; Elsevier BV; Volume: 41; Issue: 1 Linguagem: Inglês

10.1111/vaa.12086

ISSN

1467-2995

Autores

Thais Mayara Menegheti, Juliana Tessália Wagatsuma, Acácio Duarte Pacheco, Beatriz Perez, Cynara M Pacheco, Caio José Xavier Abimussi, Paulo PS dos Santos, Valéria NL de Souza Oliva,

Tópico(s)

Ion channel regulation and function

Resumo

Objective The present study aimed to investigate the influence of methadone on cardiorespiratory parameters, electrocardiogram and clinical sedation in dogs. Further possible side effects are reported. Study design Prospective experimental cross-over study. Dogs Eight, 1–4-year-old, various breeds of dogs of both genders weighing 9–36 kg. Methods Each dog was treated three times: methadone 0.3 mg kg−1 (M0.3), 0.5 mg kg−1 (M0.5) and 1.0 mg kg−1 (M1.0) intramuscularly. Respiratory rate, heart rate and arterial blood pressure were recorded as well as electrocardiographic evaluation of lead II. Clinical sedation in each treatment received a score (0–3) after drug administration and at 30 minute intervals until scores and measurements returned to baseline values. Results A significant decrease in heart rate was seen with each dose of methadone and bradycardia (HR<60 bpm) was noted in a few dogs at each dose. A clinically significant arrhythmia occurred in one dog at 1 mg kg−1 that required reversal with butorphanol. There was no significant difference in SAP, MAP and DAP between treatments. Some side effects such as salivation, defecation, vocalization and panting, after administration of methadone were observed. There were no differences in mean values of heart rate, P-wave and QRS complex duration and QT interval between treatments. Conclusion and clinical relevance Methadone administration was associated with panting and a decrease in heart rate at all doses tested in this study. The cardiac rhythm should be monitored carefully in dogs when methadone is administered on its own, especially at higher doses.

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