Limitations of these analgesics include, but are not limited to:
- The need for repeat oral or injectable administration (which places patients at risk for analgesic gaps and consumes valuable technician time).
- The need for advanced equipment to administer a constant rate infusion.
- Concerns over untoward side effects (e.g., sedation, gastrointestinal upset) of varying severity, even at clinically recommended dosages.
One of the most effective means of preventing the transduction and transmission of pain is through the use of local anesthetics. Current methods of providing local anesthetics include wound/tissue infiltration, lidocaine strips, topical creams, regional nerve blocks, epidurals, and the placement of soaker catheters. Although the use of local anesthetics perioperatively is supported by the American Animal Hospital Association (AAHA)/American Association of Feline Practitioners (AAFP)3 and World Small Animal Veterinary Association (WSAVA) Pain Guidelines (https://www.wsava.org/sites/default/files/jsap_0.pdf)4 there are limitations that function as barriers to their use.
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Long-Acting Local Anesthetics Video
These limitations include:
- Technical difficulty associated with some nerve and epidural blocks.
- Potential complications of the indwelling soaker catheter.
- Short duration of action (< 8 hours) of the available formulations of local anesthetics.
There are numerous local anesthetics available for clinical use in the perioperative period with established safety and efficacy profiles, though none are approved for use in dogs.4 Bupivacaine HCl was introduced into clinical practice in the early 1960s and is now one of the most commonly used and longest-acting local anesthetics, but its clinical benefit is limited by a duration of action that rarely exceeds 8 hours.5
Altogether, the limitations of currently available post-operative analgesics indicate an unmet need for better post-operative pain management. A long-acting local anesthetic that provides pain management for veterinary patients for up to 72 hours and can be added to the multi-modal analgesic arsenal could satisfy this unmet need.
3. Epstein ME, Rodonm I, Grllftnhogtn G, et al. 2015 AAHAIAAFP pain management guidelines for dogs and cots./ Fe/int Med Surg. 2015;17(3):251·272.
4. Mathews K, Kronen PW, Lascelles D, et al. Guidelines for recognition, assessment and treatment of pain. J Small Ani. 2014;55(6):E10-E68.
5. Lascelles BDX, Kirkby Shaw K. (2016), An extended release local anaesthetic: potential for future use in veterinary surgical patients? Vet Med Sci, 2:229-238. doi:10.1002/vms3.43