Pilot evaluation of a novel unilateral onychectomy model and efficacy of an extended release buprenorphine product

Multicentered masked placebo-controlled phase 3 clinical study of an extended duration transdermal buprenorphine solution for post-operative pain in cats

A prospective, double masked, placebo-controlled, multicentered phase 3 clinical study was conducted to evaluate the safety and effectiveness of transdermal buprenorphine solution (TBS) for the control of post-operative pain in cats. A total of 228 cats from 12 US investigational sites met the enrollment criteria of which 107 placebo- and 112 TBS-treated cats were included into the per protocol efficacy analysis. The dose of TBS was 8 mg (0.4 ml) to cats 1.2 to 3 kilograms and 20 mg (1 ml) to cats >3 to 7.5 kilograms applied topically to the dorsal unclipped cervical skin 1-2 h prior to the undergoing elective surgical reproductive sterilization in conjunction with forelimb onychectomy. Interactive pain assessments and physiological variables were quantified through 96 h following recovery from anesthesia, and rescue analgesia was administered any time that pain control was scored inadequate. Cats requiring rescue analgesia or experiencing an adverse event suspected to be treatment related were considered treatment failures. Sixty-five and 23 cats were considered treatment failures in the placebo and TBS groups, respectively, with most occurring on the day of surgery. The treatment success rates were 0.40 (95% confidence interval [CI]: [0.28-0.53]) and 0.81 (95% CI: [0.70-0.89]) in the placebo and TBS groups, respectively, and the difference was significant (p < .05). Adverse events occurred at a similar frequency and were not clinically meaningful in either treatment group. The post-operative body temperatures over the duration of the study were on average 0.35 (95% CI: [0.20-0.50]) °C higher than baseline in TBS-treated cats and were not clinically meaningful, an observation typical of opioids in cats. These results serve as substantial evidence that TBS is safe and effective for the control of orthopedic and soft tissue post-operative pain in cats when a single topical dose is applied 1-2 h prior to surgery.

Controlled, non-inferiority trial of bupivacaine liposome injectable suspension

OBJECTIVES

Recently, a bupivacaine liposome injectable suspension (BLIS) became commercially available in the veterinary market that may provide local analgesia for 72 h. The purpose of this study was to compare a BLIS incisional block with a control protocol in cats after ovariohysterectomy (OHE). The hypothesis was that a BLIS block would provide equivalent pain relief.

METHODS

This study was designed as a randomized, double-blind, non-inferiority trial. Students performed an OHE followed by a two-layer incisional and body wall block with either standard bupivacaine (control) or BLIS. Postoperatively, cats in the control group received robenacoxib, whereas the BLIS cats received saline. All cats were evaluated using the feline Glasgow Composite Measure Pain Scale (GCMPS) at multiple time points postoperatively.

RESULTS

There were 24 control cats and 23 BLIS cats. One cat from each group required rescue medication. The mean GCMPS scores were low and the groups were equivalent at all time points (P <0.05). This study showed that BLIS was equivalent to the control group up to 42 h and pain scores remained low up to 68 h after surgery.

CONCLUSIONS AND RELEVANCE

BLIS incisional block is equivalent to a control pain protocol and reduces the need for continued postoperative drug administration.

Kinetic analysis of felines landing from different heights

Background

Kinetic motion analysis has been used in canines and equines as a fundamental objective evaluation measurement. Cats are very capable jumpers, and this ability has biomimetic applications. It is essential to understand movement patterns and physical adaptations of this species, as cats are popular pets for humans. Further to this, motion analysis of a cat's movement patterns may provide potentially valuable information in relation to limb disease and injury. Therefore, the aim of this study was to investigate kinetic differences in cats when landing from varying preselected controlled heights.

Methods

The peak vertical force (PVF) and paw contact area (CA) of both the forelimbs and hindlimbs were collected from seven healthy Chinese domesticated cats while landing from heights of 30 cm, 50 cm, 70 cm and 90 cm respectively. The falling motivation for the cats was facilitated with the use of a flip board. This device provided the basis for the cats to land passively.

Results

The results indicated that the PVF of all examined limbs (fore right, fore left, hind right, hind left) significantly increased as the height increased. When the PVF from the hindlimbs and forelimbs were compared, the forelimbs recorded significantly greater values for all heights examined (P < 0.001). The PVF of the hindlimbs was symmetrical at all heights, but forelimb symmetry only occurred at the lower heights. The hindlimbs demonstrated larger CA than the forelimbs measured from all heights on landing (P < 0.001). Moreover, the paw CA on the left and right limbs were symmetrical.

Discussion

The paw CA of cats may be an effective parameter to evaluate abnormalities or diseases in the limbs of cats. Additionally, these findings highlight how cats land from varying heights, which may also provide reference values for the bionic design of artificial limbs for felines and treatment for limb diseases in this species.

The pharmacokinetics and analgesic effects of extended-release buprenorphine administered subcutaneously in healthy dogs

Buprenorphine is a partial μ agonist opioid used for analgesia in dogs. An extended-release formulation (ER-buprenorphine) has been shown to provide effective analgesia for 72 hr in rats and mice. Six healthy mongrel dogs were enrolled in a randomized, blinded crossover design to describe and compare the pharmacokinetics and pharmacodynamics of ER-buprenorphine administered subcutaneous at 0.2 mg/kg (ER-B) and commercially available buprenorphine for injection intravenously at 0.02 mg/kg (IV-B). After drug administration, serial blood samples were collected to measure plasma buprenorphine concentrations using liquid chromatography/mass spectrometry detection. Heart rate, respiratory rate, body temperature, sedation score, and thermal threshold latency were recorded throughout the study. Median (range) terminal half-life, time to maximum concentration, and maximum plasma concentration of ER-buprenorphine were 12.74 hr (10.43-18.84 hr), 8 hr (4-36 hr), and 5.00 ng/ml (4.29-10.98 ng/ml), respectively. Mild bradycardia, hypothermia, and inappetence were noted in both groups. Thermal threshold latency was significantly prolonged compared to baseline up to 12 hr and up to 72 hr in IV-B and ER-B, respectively. These results showed that ER-buprenorphine administered at a dose of 0.2 mg/kg resulted in prolonged and sustained plasma concentrations and antinociceptive effects up to 72 hr after drug administration.