A comparison of detomidine in combination with saline, morphine or methadone in horses submitted to experimental oral stimuli

Abstract

A comparison of detomidine in combination with saline, morphine or methadone in horses submitted to experimental oral stimuli Comparação entre a associação da detomidina à solução salina, à morfina ou à metadona em cavalos submetidos aos estímulos experimentais na cavidade oral AbstractThis study aimed to compare the sedative and cardiopulmonary effects of detomidine in combination with saline, morphine or methadone and to determine whether the addition of these opioids increases the degree of sedation in horses submitted to experimental oral stimuli. In a blinded, randomized, experimental study, six adult mares were evaluated using a crossover design with at least 15 days between trials: 10µg/kg detomidine in combination with saline (D/SAL), 0.1mg/kg morphine (D/ MORPH) or 0.1mg/kg methadone (D/METH). The degree of sedation, response to oral stimuli and cardiopulmonary parameters were monitored for 120 minutes. Parametric data were analyzed using the ANOVA and Tukey's tests, and non-parametric data were analyzed with the Kruskal-Wallis and Friedman's tests with the post-Dunn test (P<0.05). The degree of sedation was significantly greater for the D/SAL than for the D/MORPH and D/METH treatments at 30 min. The horses´ responses to the oral stimuli decreased significantly following all treatments at 5 and 30 min from baseline values. The heart rate, respiratory rate, arterial pH and blood gas variables were all similar among the treatment groups. Mean arterial blood pressure was significantly higher in the D/MORPH group when compared with the D/SAL group between 75 and 120 min. It was concluded that all treatments provided sedative effects with mild cardiopulmonary changes. However the addition of morphine or methadone to detomidine did not improve the degree of sedation in horses submitted to experimental oral stimuli. Key words: Alpha 2 adrenoreceptor agonists, dental, equine, opioids ResumoObjetivou-se comparar os efeitos sedativos e cardiorrespiratórios da detomidina associada à solução salina, à morfina ou à metadona e determinar se a associação desses opioides poderia incrementar o grau de sedação em cavalos submetidos aos estímulos na cavidade oral. Em estudo cego, com delineamento aleatório foram avaliadas 06 éguas, com intervalo mínimo de 15 dias entre cada avaliação, sendo submetidos aos protocolos de sedação com detomidina (10mg/kg, IV) associada à solução salina (D/SAL), a 0,1mg/kg (IV) de morfina (D/MORF) ou a 0,1mg/kg (IV) de metadona (D/MET).

Effects of lidocaine associated with detomidine on sedation of horses undergoing dental procedures

“…The literature shows other studies assessing the association of α-2 agonists with other drugs to perform dental procedures, in which the association between 10 µg kg −1 of detomidine and morphine or methadone, both at a dose of 0.1 mg kg −1 , promoted a reduction of 44 and 41% in head height, respectively. This reduction was lower than that observed when using detomidine alone, which presented a 70% reduction (Guilhen et al, 2015), a value similar to that found in the present study for GD and GDL. The authors used the same assessment scale as the present study, with lower scores than the basal from 5 to 30 min after treatment administration, with no differences between scores in relation to basal after 30 minutes (Guilhen et al, 2015).…”

“…This reduction was lower than that observed when using detomidine alone, which presented a 70% reduction (Guilhen et al, 2015), a value similar to that found in the present study for GD and GDL. The authors used the same assessment scale as the present study, with lower scores than the basal from 5 to 30 min after treatment administration, with no differences between scores in relation to basal after 30 minutes (Guilhen et al, 2015). Such difference can be attributed to the form of administration, as the previous study used single bolus and the present study administered drugs in continuous infusion, with no reduction in sedation scores over time.…”

“…The degree of sedation consisted of using an adaptation of a specific scale to assess sedation in horses undergoing dental procedures (Roscoe, 2007). This scale was also used in a similar study (Guilhen et al, 2015). The periodontal sensitivity was removed for this adaptation due to the impossibility of the measurement during the dental procedure (Table 1).…”

“…Detomidine associated with morphine or methadone for dental procedures has not intensified sedation compared to detomidine alone (Guilhen, Cassu, Diniz, Giuffrida, & Duarte, 2015). Similarly, the association between lidocaine and xylazine has not potentiated xylazine sedation but increased the nociceptive threshold, measured by electrical stimulation (Souza, Monteiro, Campagnol, Ramos, & Frasson, 2012).…”