Comparison of Nociceptive Effects of Buprenorphine, Firocoxib, and Meloxicam in a Plantar Incision Model in Sprague-Dawley Rats

Due to their reduced frequency of dosing and ease of availability, NSAIDs are generally preferred over opioids for rodent analgesia. We evaluated the efficacy of the highly COX2-selective NSAID firocoxib as compared with meloxicam and buprenorphine for reducing allodynia and hyperalgesia in rats in a plantar incision model of surgical pain. After a preliminary pharmacokinetic study using firocoxib, Sprague-Dawley rats (n = 12 per group, 6 of each sex) were divided into 6 groups: no surgery (anesthesia only), saline (surgery but no analgesia), buprenorphine (0.05 mg/kg SC every 8 h), meloxicam (2 mg/kg SC every 24 h), and 2 dosages of firocoxib (10 and 20 mg/kg SC every 24 h). The nociception assays were performed by using von Frey and Hargreaves methodology to test mechanical allodynia and thermal hyperalgesia. These assays were performed at 24 h before and at 20, 28, 44, and 52 h after start of surgery. None of the analgesics used in this study produced significantly different responses in allodynia or hyperalgesia from those of saline-treated rats. In the Hargreaves assay, female saline-treated rats experienced significantly greater hyperalgesia than did males. These findings add to a growing body of literature suggestingthat commonly used dosages of analgesics may not provide sufficient analgesia in rats experiencing incisional pain.

Comparison of two inhibitors of E-type prostanoid receptor four and carprofen in dogs with experimentally induced acute synovitis

OBJECTIVE

To investigate the ability of a proprietary antagonist of E-type prostanoid receptor (EP) 4, grapiprant, and carprofen to attenuate lameness attributable to urate-induced synovitis in dogs.

ANIMALS

5 purpose-bred hound-cross dogs.

PROCEDURES

A blinded, 3-way crossover study was performed. Dogs received each of 3 treatments (L-766, a proprietary antagonist of EP4; 4.0 mg/kg), grapiprant (an antagonist of EP4; 2.0 mg/kg), and carprofen (4.4 mg/kg); dogs received 4 doses of each treatment (14 and 2 hours before and 22 and 46 hours after urate injection). Synovitis was induced by intra-articular injection of sodium urate. Measurements (vertical ground reaction forces and clinical lameness scores) were obtained immediately before (0 hours; baseline) and 6, 12, 24, 36, and 48 hours after sodium urate injection. All data were analyzed with repeated-measures ANOVA.

RESULTS

Lameness scores at 6 hours were significantly higher than baseline lameness scores for all treatments. Lameness scores for the grapiprant treatment remained significantly higher at 12 and 24 hours, compared with baseline lameness scores. Lameness scores for the carprofen treatment were significantly lower than lameness scores for the grapiprant treatment at 6, 12, and 24 hours. Analysis of peak vertical force and vertical impulse data revealed a pattern similar to that for lameness scores. Treatment with L-766 resulted in a significantly higher vertical impulse at 48 hours than did treatment with carprofen or grapiprant.

CONCLUSIONS AND CLINICAL RELEVANCE

In these dogs, carprofen was the most effective treatment for attenuating lameness induced by injection of sodium urate, and grapiprant was the least effective treatment.

Six-month safety evaluation of robenacoxib tablets (Onsior™) in dogs after daily oral administrations

Background

Robenacoxib is a non-steroidal anti-inflammatory drug available for canine and feline use for the control of pain and inflammation marketed as Onsior™. The aim of this target animal safety study was to evaluate the 6-month safety profile of oral robenacoxib administration. It was a randomized, negative-controlled, parallel group study. Thirty-two healthy, young, experimentally naïve, purebred Beagle dogs were administered 0 (sham control, Group 1), 2, 6, and 10 mg/kg robenacoxib (corresponding to the upper end of the dosage range [1X, Group 2] and multiples thereof [3X and 5X, Group 3 and 4]), orally once daily for 6 months. Assessment of safety included general health and clinical observations, physical, neurological, ophthalmological and electrocardiographic examinations, gross and histopathological examinations and clinical pathology evaluations. Blood samples were collected for toxicokinetic assessment of robenacoxib.

Results

No serious adverse events were reported. When compared with control, no treatment effect was observed for body weight, feed or water consumption, clinical pathology, urinalysis and fecal examination parameters. There were no treatment-related changes in stifle joint tissues and microscopic/histopathology examinations of all tissues/organs were normal. Salivation and soft feces were noted in all groups but observed more frequently in the treated groups as compared with control. On Day 178, increased buccal mucosal bleeding times were observed in two treated animals (Group 3 and 4) and one dog in Group 4 displayed a retinal change. Decreased hopping and conscious proprioception was noted in four treated dogs. One dog in Group 2 had ventricular premature complexes. Post-mortem changes included mild, red foci on the cecum in one dog (Group 3) and minimal duodenal discoloration in one dog (Group 4), with no corresponding histological findings in either dog. Ovarian weights were decreased in females from Group 3 and 4 with no gross or histological changes in the ovaries. Blood concentrations of robenacoxib confirmed systemic exposure of treated dogs. Exposure increased with increasing doses and there were no accumulation of robenacoxib in blood.

Conclusions

Robenacoxib was well tolerated at doses from 2 to 10 mg/kg/day and this 6-month study supports the safe use of Onsior™ (robenacoxib) tablets in dogs for the intended dosing regimen.

Analgesic efficacy of oral firocoxib in ovariohysterectomized cats

The postoperative analgesic effects of firocoxib in ovariohysterectomized cats were observed. Twenty-four cats were divided into 3 groups: control (no medicine), firocoxib-1 (1 mg/kg/day) and firocoxib-3 (3 mg/kg/day). Colorado pain scale scores (CPSS), composite pain scores (CPS), and buccal mucosal bleeding times (BMBT) were recorded in blinded fashion before induction and 2, 5, 8, 24, 30, and 48 h post-operation. The average CPSS (mean ± SEM) over 2 to 48 h post-operation in firocoxib-3 (0.4 ± 0.1) was significantly lower than that of the control (0.7 ± 0.2; p = 0.004), but that of firocoxib-1 (0.5 ± 0.2) was not different from that of the control (p = 0.40). The mean CPS of firocoxib-3 was significantly lower than that of the control at 24 h post-operation (p = 0.04); nonetheless, there was no significant difference in mean CPS between firocoxib-1 and control groups at all intervals. BMBT and body temperature were within normal limits in all groups. However, reversible azotemia was identified in two firocoxib-3 cats at 72 h post-operation. One firocoxib-3 cat vomited once at 48 h post-operation. In conclusion, firocoxib-3 is helpful for postoperative pain control in cats; however, gastrointestinal irritation and renal function side effects may occur.

Efficacy and Safety of Injectable Robenacoxib for the Treatment of Pain Associated With Soft Tissue Surgery in Dogs

Background

Nonsteroidal anti‐inflammatory drugs (NSAIDs) are used routinely to control pain and inflammation after surgery in dogs. Robenacoxib is a cyclooxygenase‐2 selective NSAID.

Hypothesis/Objective

Assess the clinical efficacy and safety of an injectable formulation of robenacoxib in dogs undergoing surgery.

Animals

Three hundred and seventeen client‐owned dogs (N = 159 robenacoxib or N = 158 placebo).

Methods

In this prospective, multicenter, randomized, masked, placebo‐controlled, parallel‐group study, dogs received a SC injection of either robenacoxib, at a target dose of 2.0 mg/kg, or placebo once prior to surgery and for 2 additional days postoperatively. Pain assessments were performed using the short form of the Glasgow Composite Measure Pain Scale (CMPS‐SF). The primary efficacy variable was treatment success/failure, with failure defined as the need for rescue therapy to control pain or withdrawal of the dog from the study due to an adverse event.

Results

Significantly (P = .006) more dogs administered robenacoxib were considered treatment successes (108 of 151, 73.7%) compared to dogs given placebo (85 of 152, 58.1%). Total pain scores (P < .01), pain at the surgery sites (response to touch, P < .01), and posture/activity (P < .05) were significantly improved at 3, 5, and 8 hours postextubation in dogs receiving robenacoxib versus placebo.

Conclusions and Clinical Importance

Robenacoxib administered by SC injection prior to surgery and for 2 additional days postoperatively was effective and well tolerated in the control of postoperative pain and inflammation associated with soft tissue surgery in dogs.

Efficacy and safety of oral robenacoxib (tablet) for the treatment of pain associated with soft tissue surgery in client-owned dogs

Background

Non-steroidal anti-inflammatory drugs (NSAIDs) have been proven to be effective in controlling peri-operative pain in dogs. Robenacoxib is an NSAID with high selectivity for the cyclooxygenase (COX)-2 isoform. The objective of this study was to assess the efficacy and safety of an oral tablet formulation of robenacoxib in client-owned dogs undergoing soft tissue surgery. The study was a prospective, multi-center, randomized, masked, placebo-controlled, parallel-group clinical trial. A total of 239 dogs were included and randomly allocated in a 1:1 ratio to receive either robenacoxib or placebo. Each dog received an oral tablet administration of either robenacoxib, at a target dose of 2 mg/kg, or placebo once prior to surgery and for two additional days post-operatively. All dogs also received a pre-anesthetic dose of 0.2 mg/kg butorphanol (intravenous or intramuscular). Pain assessments were performed using the short form of the Glasgow Composite Measure Pain Scale. Robenacoxib was compared to the placebo group on a success/failure basis. Treatment failure was defined as the need for rescue therapy to control post-operative pain.

Results

Significantly (P = 0.019) more dogs administered robenacoxib were considered treatment successes (89 of 116, 76.72%) compared to dogs given placebo (74 of 115, 64.35%). The percentage of treatment failure was therefore 23.28% in the robenacoxib and 35.65% in the placebo group. The least squares mean total pain scores were significantly different between groups and in favor of robenacoxib at 3 and 5 hours (P < 0.05) and 8 hours post-extubation (P < 0.01). Pain at the surgery sites (response to touch) was also significantly improved at 3, 5 and 8 hours post-extubation in dogs receiving robenacoxib versus placebo (P < 0.01). In addition, a significant overall improvement in posture/activity was revealed with robenacoxib having lower scores versus placebo (P < 0.01). No significant differences between the robenacoxib and placebo groups in the frequency of reported adverse events were observed.

Conclusions

Robenacoxib by oral (tablet) administration was effective and well tolerated in the control of peri-operative pain and inflammation associated with soft tissue surgery in dogs.

Combination of radiation therapy and firocoxib for the treatment of canine nasal carcinoma

Carcinomas represent two-thirds of canine nasosinal neoplasms. Although radiation therapy (RT) is the standard of care, the incidence of local recurrence following treatment is high. Cyclooxygenase-isoform-2 (COX-2) is expressed in 71-95% of canine nasal carcinomas and has been implicated in tumor growth and angiogenesis. Accordingly, COX-2 inhibition seems rational to improve outcome. Dogs with histologically confirmed, previously untreated nasal carcinomas were randomized to receive the combination of a selective COX-2 inhibitor (firocoxib) and palliative RT (Group 1) or RT and placebo (Group 2). Patients were regularly monitored with blood tests, urinalysis, and computed tomography. Pet owners were asked to complete monthly a quality-of-life questionnaire. Twenty-four dogs were prospectively enrolled. According to Adams modified system, there were five stage 1, five stage 2, three stage 3, and 11 stage 4 tumors. Two dogs had metastases to regional lymph nodes. Median progression-free interval and overall survival were 228 and 335 days in Group 1 (n = 12) and 234 and 244 days in Group 2 (n = 12). These differences were not statistically significant. The involvement of regional lymph nodes was significantly associated with progression-free interval and overall survival (P = 0.004). Quality of life was significantly improved in Group 1 (P = 0.008). In particular, a significant difference was observed for activity and appetite. Although not providing a significant enhancement of progression-free interval and overall survival, firocoxib in combination with RT is safe and improved life quality in dogs with nasal carcinomas.

Robenacoxib versus meloxicam for the management of pain and inflammation associated with soft tissue surgery in dogs: a randomized, non-inferiority clinical trial

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are used routinely to control pain and inflammation after surgery in dogs. Robenacoxib is a new NSAID with high selectivity for the cyclo-oxygenase (COX)-2 isoform of COX. The objective of this study was to evaluate the efficacy and tolerability of robenacoxib for the management of peri-operative pain and inflammation associated with soft tissue surgery in dogs. The study was a prospective, randomized, blinded, positive-controlled, non-inferiority, multi-center clinical trial. A total of 174 dogs undergoing major soft tissue surgery were included and randomly allocated in a 2:1 ratio to receive either robenacoxib (n = 118) or the positive control, meloxicam (n = 56). Each dog received an initial dose subcutaneously prior to surgery (robenacoxib 2 mg/kg, meloxicam 0.2 mg/kg), followed by daily oral doses (robenacoxib 1-2 mg/kg, meloxicam 0.1 mg/kg) for 12 days (range 10-14) after surgery. Pain and inflammation were assessed subjectively using the Glasgow Composite Pain Scale (GCPS) by clinicians as the primary end point and additional evaluations by the clinicians and animal owners as secondary endpoints.

RESULTS

Both treatments provided similar pain control, with no significant differences between groups for any efficacy variable using non-parametric analyses (Mann-Whitney U test). In no dog was analgesic rescue therapy administered. Non-inferior efficacy of robenacoxib compared to meloxicam was demonstrated statistically for the primary and all secondary endpoints using parametric analysis of variance, although the data were not normally distributed even after log transformation. For the primary endpoint (reciprocal of the modified GCPS score), the relative efficacy of robenacoxib/meloxicam was 1.12 with a 95% confidence interval of 0.97-1.29.

CONCLUSION

A treatment regimen of robenacoxib by subcutaneous injection followed by oral tablets had good tolerability and non-inferior efficacy compared to meloxicam for the management of peri-operative pain and inflammation associated with soft tissue surgery in dogs.