Effect of Tapentadol on Dogs’ Minimum Alveolar Concentration (MAC) of Isoflurane

To evaluate the effect of oral administration of 10 mg kg^-1 tapentadol on dogs' minimum alveolar concentration of isoflurane. The MAC of isoflurane was determined in seven dogs without previous medication (Group MAC_ISO) and 2 h 30 min after the administration of 10 mg kg^-1 of tapentadol orally (Group MAC_ISO+TAP). The MAC was determined by pinching the fourth finger of the pelvic limb. Data normality was analyzed using the Shapiro-Wilk test. Student's t-test was used to evaluate the effect of tapentadol on isoflurane MAC and cardiovascular variables. The minimum alveolar concentration obtained in the Group MAC_ISO was 1.52 ± 0.02%, and in the Group MAC_ISO+TAP, it was 1.47 ± 0.03%, observing a significant statistical difference between groups (<i>p</i> = 0.01). The reduction in the MAC caused by administering 10 mg kg^-1 of Tapentadol was 3.29%. No statistically significant differences were observed when the heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure were compared between groups. The oral administration of 10 mg kg^-1 tapentadol reduces dogs' minimum alveolar concentration of isoflurane without alterations in the heart rate and systemic blood pressure.