Evaluation of the effects of methadone and tramadol on postoperative analgesia and serum interleukin-6 in dogs undergoing orthopaedic surgery

Abstract

BackgroundAcute postsurgical pain is of great interest due to potential risk of becoming chronic if not treated properly, worsening patient’s recovery and quality of life. Twenty-eight dogs with ruptured cruciate ligaments were divided into three groups that received intramuscular injections of 4 mg/kg of tramadol (TRA), 0.5 mg/kg of methadone (MET0.5), or 0.7 mg/kg of methadone (MET0.7). Physiological parameters (heart and respiratory rates and blood pressure) were evaluated at specified times: baseline (TBL), 1 (T1), 2 (T2), 4 (T4), 6 (T6), and 24 (T24) hours after premedication. Pain scores were described by visual analogue scale (VAS), modified Glasgow Composite, and Colorado University Acute Pain scales. Blood samples for measurement of interleukin (IL)-6 were collected at TBL, T1, T6, and T24. This was a prospective, randomised investigation to evaluate the efficacy of tramadol and methadone as premedications in dogs undergoing osteotomies.ResultsThere were no statistically significant differences between groups with respect to age, weight, gender, surgery time, and time to extubation. Heart rate, respiratory rate, and blood pressure values were maintained within acceptable ranges, and a reduction was observed at T2 in MET0.5 and MET0.7 compared with TBL. Increases in VAS scores were observed in TRA at T4 compared with TBL, T1, and T24 and between T1 and T6 (p < 0.001). In MET0.5, there was significant increase in VAS score at T4 compared with T1 (p < 0.001). TRA and MET0.5 showed significantly higher mean ± SD VAS scores (3.4 ± 2.5 and 2.5 ± 2.6, respectively) than MET0.7 (1.1 ± 1.5) at T4 (p < 0.001). TRA showed greater demand of rescue analgesia (four animals in T4 and two in T6) (p < 0.037). There were no statistically significant differences in sedation scores, Colorado Scale scores, or interleukin levels between groups and time points.ConclusionsMethadone given as premedication in doses of 0.7 mg/kg was better at controlling pain compared with lower doses and tramadol. However, dosage increases, administered as rescue analgesia, promoted adequate pain control even in tramadol group. Influence of these analgesics on IL-6 release could not be demonstrated, but significant levels were not found.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-014-0194-7) contains supplementary material, which is available to authorized users.

Pre-emptive methadone or tramadol analgesia for mastectomy and ovariohysterectomy in bitches

“…Methadone resulted in fewer rescue analgesia requirements, less post-operatory analgesic consumption, and better post-operative pain scores than pre-emptive tramadol. The findings from this study corroborate the results of Cardozo et al (2014), who compared tramadol to two different doses of methadone (0.5-0.7 mg/Kg) in dogs subjected to orthopaedic surgery. This effect may be attributed to the wide action of methadone on the nociceptive pathway, giving it superior antinociceptive potency and duration (Gourlay et al 1982;Sarrau et al, 2007), thus leading to a more effective block of central sensitization (Dyson, 2008;Gottschalk et al, 2011).…”

“…On the other hand, the MET group exhibited significantly higher MAP at certain times (10, 70, 90, 100 min) and lower HR (non-significant 10 to 50 min) than the TRA group. However, these parameters are considered to be within the expected ranges and are in agreement with Pereira et al (2013) and Cardozo et al (2014). The cardiovascular effects of methadone are attributed to elevated blood argininevasopressin levels that increase peripheral vascular resistance and, consequently, MAP elevation and reflexive HR decrease (Hellebrekers et al, 1989;Maiante et al, 2008).…”

“…These analgesics are presented as appropriate therapeutic options in the prevention and control of post-operative pain derived from aggressive surgical procedures in dogs (Mastrocinque and Fantoni, 2003;Pereira et al, 2013;Teixeira et al, 2013;Cardozo et al, 2014). However, due to the importance of NMDA receptors on central sensitization pathophysiology (Sarrau et al, 2007), we hypothesize that methadone could provide acceptable analgesia, maintain cardiorespiratory physiology, and lead to less anesthetic consumption than tramadol.…”

Extracorporeal shock wave therapy improves short‐term limb use after canine tibial plateau leveling osteotomy

“…Reported complications associated with ESWT include mild bruising, redness, transient superficial pain at the treatment site, and the requirement for sedation or general anesthesia for treatment . Subjective pain evaluation 24 hours after surgery in this study may not have been of sufficient resolution to detect differences between treatments, although the rubric used is well established for comparison of postoperative comfort levels . More objective forms of pain evaluation, such as kinetic gait, mechanical threshold testing with an algometer, or stance analysis, could have been performed …”

The present and future of opioid analgesics in small animal practice

“…In addition, the nonopioid mechanisms of action of tramadol produced limited antinociception in an acute pain model in dogs (Kögel et al ., ). NSAIDs and pure μ ‐opioid receptor agonists provided more effective analgesia when compared with tramadol in dogs undergoing orthopedic and ophthalmic procedures (Cardozo et al ., ; Delgado et al ., ).…”