Comparison of bupivacaine liposome injectable solution and fentanyl for postoperative analgesia in dogs undergoing limb amputation.

OBJECTIVE: The objectives of the study were to compare the clinical efficacy and adverse effects of two analgesic protocols consisting of bupivacaine liposome injectable solution (BLIS) and 0.5% bupivacaine and fentanyl for postsurgical analgesia in dogs undergoing limb amputation. STUDY DESIGN: Randomized, double-blind, prospective, controlled, intent-to-treat, clinical noninferiority trial. ANIMALS: Forty client-owned dogs. METHODS: Dogs undergoing amputation were randomly assigned to either the BLIS or control group. Postoperative pain, sedation, nausea, and amount eaten were assessed using appropriate scales at 6, 12, 18, and 24 h by trained individuals blinded to the treatment protocol. Rescue analgesia was provided for Glasgow composite measure pain scale (short form) (CMPS-SF) scores of 5 or above. Clients were requested to pain score their dogs at home using a visual analogue scale (VAS) for 48 h following discharge. RESULTS: Forty dogs completed this study (20 control dogs and 20 BLIS dogs). The BLIS and control groups were equivalent for sedation, nausea, amount eaten, and pain, at all time periods except at 6 h (p < .01), when the BLIS group pain score was lower. CONCLUSION: The BLIS provided equivalent analgesia with fewer adverse effects than fentanyl constant rate infusion (CRI) following limb amputation. Rescue analgesia was provided to five dogs in the BLIS group and four in the control group, and there was no statistical difference. Nausea scores did not differ statistically. CLINICAL SIGNIFICANCE: As BLIS provides equivalent analgesia, this may allow for decreased reliance on opioids in the immediate postoperative period.

A Study and Review of Effects of Botulinum Toxins on Mast Cell Dependent and Independent Pruritus.

Pruriceptive itch originates following activation of peripheral sensory nerve terminals when pruritogens come in contact with the skin. The ability of botulinum neurotoxins (BoNTs) to attenuate transmitter release from afferent terminals provides a rationale for studying its effect on pruritus. This study investigated the effects of BoNT/A1 and BoNT/B1 on mast cell dependent (Compound 48/80:48/80) and independent (Chloroquine:CQ) scratching. C57Bl/6 male mice received intradermal injection of 1.5 U of BoNT/A1, BoNT/B1 or saline 2, 7, 14 and 21 days prior to ipsilateral 48/80 or CQ at the nape of the neck. Ipsilateral hind paw scratching was determined using an automated recording device. The effect of BoNTs on 48/80 mediated mast cell degranulation was analyzed in human and murine mast cells and the presence of SNAREs was determined using qPCR, immunostaining and Western blot. Pre-treatment with BoNT/A1 and BoNT/B1 reduced 48/80 and CQ induced scratching behavior starting on day 2 with reversal by day 21. Both serotypes inhibited 48/80 induced mast cell degranulation. qPCR and immunostaining detected SNAP-25 mRNA and protein, respectively, in mast cells, however, Western blots did not. This study demonstrates the long-lasting anti-pruritic effects of two BoNT serotypes, in a murine pruritus model using two different mechanistically driven pruritogens. These data also indicate that BoNTs may have a direct effect upon mast cell degranulation.