Objectives. The aim of the study is to compare the sedative, cardiorespiratory, echocardiographic, and blood gas effects of dexmedetomidine and methadone associated or not with midazolam for restraint chemistry in cats. Methods. Eighteen healthy young cats (4.06±0.48kg) were randomly sedated with two protocols, through the intramuscular route: dexmedetomidine (5µg.kg⁻¹), methadone (0.3mg.kg⁻¹) and midazolam (0.3mg.kg⁻¹) (DMTM, n=9), or dexmedetomidine (7.5µg.kg⁻¹) and methadone (0.3mg.kg⁻¹) (DMT, n=9). The cardiorespiratory parameters were measured at baseline, 5 and 10 minutes after pharmacological latency. The sedation, analgesia, and muscle relaxation scores were assessed before and 5 minutes after pharmacological latency, while arterial blood gas analysis and echocardiography were assessed before and after 10 or 15 minutes, respectively. Results. There was no difference between the protocols regarding the cardiorespiratory, blood gas, and echocardiographic parameters used. The scores for sedation, analgesia, and muscle relaxation also did not differ between the protocols, with the degree of sedation, analgesia, and myorelaxation considered satisfactory in both groups. A significant decrease in heart rate (HR) was observed after administration of the sedative protocols, reaching a maximum reduction at T10 (46 and 53 reduction in the DMT and DMTM groups, respectively). The reduction in HR had an impact on echocardiographic parameters such as CO, which decreased 53 and 56 in the DMT and DMTM groups, respectively. There was a significant reduction in PaO₂, SaO₂, ejection fraction, and fractional shortening in both protocols. SpO₂ decreased significantly after 5 minutes of sedation in the DMT group, but with a minimum mean SpO₂ of 92 in T5. The respiratory rate decreased significantly at 5 and 10 minutes in the DMTM group, while PaCO₂ increased in both groups, indicating respiratory depression caused by the drugs. Conclusions and Relevance. The study pointed out that both sedative protocols can be recommended for clinical sedation of young and healthy cats in the doses used. However, both protocols resulted in cardiorespiratory depression in cats and also the particularities of the animals should be evaluated regarding reducing cardiac output by more than 50.

A sedação para o exame odontológico, em estação, nos equinos é essencial para facilitar o manejo e garantir um exame de excelência. O presente estudo objetivou avaliar se o diazepam associado à detomidina potencializaria a sedação do agonista α2 (detomidina), principalmente pela redução do movimento da língua e mastigação sem excessiva desestabilização. Foram examinados 12 equinos adultos de diferentes idades, raças e sexos submetidos a correção dos arcos dentários e distribuídos aleatoriamente entre dois tratamentos: detomidina (20 µg.kg-1, IV) e diazepam (20 µg.kg-1, IV) (DD; n=6) ou detomidina (20 µg.kg-1, IV) e solução salina de NaCl 0,9% (DS; n=6). Foram avaliados o relaxamento e a exposição da língua, frequência cardíaca, intervalo PR, frequência respiratória, pressão arterial sistólica, temperatura retal, bloqueios atrioventriculares de segundo grau, grau de ataxia, movimento da cabeça, em nove momentos. E a distância da cabeça ao solo (HHAG) foram avaliadas em três momentos. Sempre que houve necessidade de aumentar a sedação, foi administrado um bolus de detomidina adicional (5µg.kg-1, IV). Todos os tratamentos proporcionaram sedação e relaxamento muscular. Foram observadas diferenças entre os momentos para o relaxamento da língua (língua VAS mm) e isto foi melhor observado em T7 para o tratamento DD e T5 para o tratamento DS e manteve-se significativamente inferior à linha de base durante todo o tempo avaliado. O presente estudo sugere que a detomidina forneceu sedação adequada em cavalos submetidos ao exame odontológico mas não há necessidade de utilizar o diazepam da forma proposta porque não foi encontrada qualquer diferença entre tratamentos para qualquer variável estudada. A adição de diazepam não melhorou a sedação e nem diminuiu o movimento da língua.

Boa constrictor snakes represent a suitable model for studying the absorption, metabolism, and elimination of tramadol due to their distinct physiological characteristics. The objective of this work was to provide preliminary data on the pharmacokinetics of tramadol and its active metabolite, O-desmethyltramadol (M1), in the plasma of Boa constrictor using liquid chromatography with fluorescence detection. Ten snakes received tramadol (5 mg kg⁻¹) both into the epaxial musculature (TRIM) and into the paravertebral vein (TRIV) with a 45-day interval between the two administration methods. Blood samples were taken at specified time points to analyze the pharmacokinetics. Data were evaluated with an independent pharmacokinetic model (R software version 4.3.0). A paired Student’s t-test was used for all parametric variables, except clearance, which was analyzed with the Wilcoxon test. A significance level of 5% was applied. The mean (range) maximum concentration of tramadol, volume of distribution, clearance, and elimination half-life for the TRIM group were 2.58 µg mL⁻¹, 10.58 ± 2.91 L kg⁻¹, 0.36 L kg⁻¹ h⁻¹, and 19.96 ± 8.34 h, respectively. For the TRIV group, these values were 3.39 µg mL⁻¹, 5.60 ± 1.69 L kg⁻¹, 0.22 L kg h⁻¹, and 17.32 ± 7.55 h⁻¹, respectively. M1 achieved maximum concentration and elimination half-lives of 0.58 µg mL⁻¹ and 49.89 ± 10.8 h, respectively, for TRIM and 0.59 µg mL⁻¹ and 35.66 ± 10.85 h for TRIV. The bioavailability of intramuscular tramadol was 61%, and M1 remained at similar concentrations for 20 min after tramadol administration in both treatments. Tramadol is rapidly biotransformed into M1 in Boa constrictors, maintaining high concentrations over an extended period. The pharmacokinetic characteristics, particularly the sustained plasma concentrations of M1, suggest potential for effective analgesia in the Boa constrictor. Furthermore, the intramuscular route provides the additional advantage of ease and practicality of administration.