Anti‐nociceptive Efficacy of Carprofen, Levomethadone and Buprenorphine for Pain Relief in Cats following Major Orthopaedic Surgery

Abstract

A placebo-controlled, randomized blind study was conducted in cats (n = 60) after fracture repair to compare the analgesic effects as well as the side-effects of carprofen, buprenorphine and levomethadone during a 5-day treatment. Cats with severe shock symptoms or increases in blood urea nitrogen (BUN) and creatinine were excluded from the study. The cats were randomly assigned to four groups (n= 15). In group 1, carprofen was administered upon extubation at an initial dose of 4 mg/kg body weight, followed by one-third of that dose three times daily on days 2 to 5. In group 2, buprenorphine was administered in a single dose of 0.01 mg/kg body weight upon extubation and subsequently every 8 h. Levomethadone (group 3) was applied according to the same scheme at a dosage of 0.3 mg/kg body weight each time. The placebo (group 4) was given at the same time intervals as the opioids. Examinations were carried out prior to anaesthesia, between 30 min and 8 h after extubation, and on the following 4 days, 1 h after administration of the analgesics or the placebo as well as 1 h before the next administration. Pain and sedation evaluation was carried out with a visual analogue system (VAS) and with the aid of a numerical estimation scale (NRS). Pain was also scored by measuring mechanical nociceptive threshold of traumatized tissue. Plasma glucose and cortisol concentration, heart rate, respiration rate, blood pressure and body temperature were measured. Furthermore, a complete blood count and clinical chemistry including BUN, creatinine, alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH), arterial blood pressure (AP), total protein and electrolytes of the cats were checked on the day of admission as well as on the last day of this study (day 5). Defaecation and urination as well as wound healing were monitored. On the basis of the mechanical nociceptive threshold of the traumatized tissue, concentrations of plasma glucose and cortisol and pain assessment using NRS and VAS, carprofen was found to have better anti-nociceptive efficacy when compared with the two opioid analgesics, while the analgesic effect of levomethadone was similar to that of buprenorphine. However, the carprofen group also showed comparably high median NRS and VAS pain scores in addition to occasional broad deviations from the group mean on the first post-operative treatment day. Sedative effects were detected for buprenorphine and levomethadone; in addition, symptoms of central excitation were noted with levomethadone. There was no indication of any clinically relevant respiratory depressive or cardiovascular effects, nor of any undesired renal, gastrointestinal or hepatic effects of the analgesics applied. However, the somewhat insensitive examination methods did not permit sufficient evaluation of side-effects, particularly on the gastrointestinal tract and the kidneys. It was found that carprofen and buprenorphine were well-tolerated analgesics for a 5-day administration in the cat, whereas levomethadone caused central excitation in some...

Analgesia for cats after ovariohysterectomy with either buprenorphine or carprofen alone or in combination

“…Buprenorphine has been shown to be superior to morphine, pethidine and oxymorphone in cats undergoing various types of surgery (Slingsby and Waterman-Pearson 1998, Dobbins and others 2002, Stanway and others 2002), but inferior to ketoprofen, meloxicam and carprofen in other studies (Slingsby and Waterman-Pearson 1998, Gassel and others 2005, Möllenhoff and others 2005). Although these results are conflicting, the dose of buprenorphine used was at the lower limit of the dosage range (0.006 to 0.01 mg/kg) for treatment of acute postoperative pain in cats.…”

Methadone and Dexmedetomidine Combination as Premedicant Agents for Ovariectomy in Cats

“…No changes in HR have been reported following methadone administration IM or SC (0.3 and 0.6 mg kg −1 , respectively) in cats (Mollenhoff et al, 2005;Bley et al, 2004). In the present study, HR values registered 20 min after injection decreased of about 28% in comparison to Tbase values, whilst during the intraoperative period no further decrease in heart rate was detected.…”

Recognition and behavioral assessment of acute pain in cats: literature review

“…Previous studies reported an increase in cortisol levels compared to baseline preoperative values (MÖLLENHOFF et al, 2005) and in cats with higher pain scores and requiring rescue analgesia (EVANGELISTA et al, 2014). However, in another study differences in physiological parameters including cortisol and β-endorphins were not observed between cats that had undergone surgery and control cats (that had not) (CAMBRIDGE et al, 2000).…”