Blinded, randomized, placebo-controlled study of the efficacy of bupivacaine liposomal suspension using static bodyweight distribution and subjective pain scoring in dogs after tibial plateau leveling osteotomy surgery.

OBJECTIVE: To compare the analgesic effect of surgical wound infiltration with liposomal bupivacaine (LB) to saline placebo in dogs after tibial plateau leveling osteotomy (TPLO). STUDY DESIGN: Blinded, randomized, placebo-controlled clinical prospective study. ANIMALS: Fifteen client-owned dogs receiving LB and 17 dogs receiving an equivalent volume of saline placebo, all with confirmed unilateral cranial cruciate ligament insufficiency. METHODS: Preoperatively and up to 48 h after surgery, Glasgow Composite Measure Short Form (CMPS-SF) pain scores were assigned and using a weight distribution platform, static bodyweight distribution (%BWdist ) to the operated limb was measured. Postoperatively, dogs also received carprofen 2.2 mg/kg subcutaneously every 12 h. Rescue analgesia was provided. Treatment success was defined as not requiring rescue analgesia over the 48-h postoperative period. RESULTS: There was no difference between treatment success, postoperative opioid consumption, CMPS-SF pain scores, or %BWdist in dogs that received surgical wound infiltration with LB compared with those receiving saline placebo, following TPLO. There was no linear correlation between CMPS-SF pain scores and %BWdist . CONCLUSION: For the population of dogs that underwent TPLO and received postoperative carprofen at our institution, LB did not provide an analgesic effect discernable by success/failure analysis, CMPS-SF pain scores, or %BWdist measurement using a weight distribution platform, compared with saline placebo. CLINICAL SIGNIFICANCE: LB may not provide detectable analgesia during the first 48 h for dogs recovering from TPLO and receiving only postoperative carprofen.

Plasma concentrations of tramadol after transdermal application of a single metered dose of a compounded tramadol gel to cats.

OBJECTIVE: To determine plasma tramadol concentrations in cats following a single dose of oral and transdermal formulations and the pharmacokinetics for and the concentration of tramadol in the transdermal formulation. ANIMALS: 8 healthy client-owned domestic shorthair cats. PROCEDURES: 1 cat was orally administered 1 dose of tramadol (2 mg/kg), and 7 cats received 1 dose of a proprietary compounded tramadol gel product (median actual dose, 2.8 mg/kg) applied to their inner pinnae. Plasma tramadol concentrations were measured with high-performance liquid chromatography-mass spectrometry at fixed times over 24 hours. RESULTS: Plasma tramadol concentrations were undetectable or much lower (range, < 1 to 4.3 ng/mL) following application of the transdermal formulation, compared with those following oral administration (maximum plasma tramadol concentration, 261.3 ng/mL [at 4 hours]). Tramadol pharmacokinetics for the transdermal formulation could not be determined. Tramadol concentrations of the transdermal gel product exceeded the estimated label dose in all analyzed gel samples, with concentrations greater than the 90% to 110% United States Pharmacopeia standard for compounded drugs. CONCLUSIONS AND CLINICAL RELEVANCE: Application of 1 dose of the proprietary transdermal formulation did not yield clinically relevant plasma tramadol concentrations in cats. Although this proprietary formulation is currently available to prescribing veterinarians, it should be used with caution.

Evaluation of serum cytokines in cats with and without degenerative joint disease and associated pain.

Degenerative joint disease is common in cats, with signs of pain frequently found on orthopedic examination and radiographs often showing evidence of disease. However, understanding of the pathophysiology of degenerative joint disease and associated pain remains limited. Several cytokines have been identified as having a role in pain in humans, but this has not been investigated in cats. The present study was performed to use a multiplex platform to evaluate the concentration of 19 cytokines and chemokines in serum samples obtained from cats with and without degenerative joint disease and associated pain. Samples from a total of 186 cats were analyzed, with cats representing a range of severity on radiographic and orthopedic evaluations and categorized by degenerative joint disease scores and pain scores. Results showed that cats with higher radiographic degenerative joint disease scores have higher serum concentrations of IL-4 and IL-8, while cats with higher orthopedic exam pain scores have higher concentrations of IL-8, IL-2, and TNF-α; increased concentration of IL-8 in degenerative joint disease and pain may be confounded by the association with age. Discriminant analysis was unable to identify one or more cytokines that distinguish between groups of cats classified based on degenerative joint disease score category or pain score category. Finally, cluster analysis driven by analyte concentrations shows separation of groups of cats, but features defining the groups remain unknown. Further studies are warranted to investigate any changes in cytokine concentrations in response to analgesic therapies, and further evaluate the elevations in cytokine concentrations found here, particularly focused on studies of local cytokines present in synovial fluid.