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Local Anesthetics

Use in Dogs and Cats

Local anesthetics are widely available in companion animal practice and have been shown to provide analgesia with little risk for untoward effects. The 2015 Pain Management Guidelines from the AAHA support the International Veterinary Academy of Pain Management position that “because of their safety and significant benefit, local anesthetics should be utilized, insofar as possible, with every surgical procedure.”3 Link to Pain Guidelines: https://www.aaha.org/public_documents/professional/guidelines/2015_aaha_aafp_pain_management_guidelines_for_dogs_and_cats.pdf

The 2015 Pain Management Guidelines from the AAHA support the International Veterinary Academy of Pain Management position that “because of their safety and significant benefit, local anesthetics should be utilized, insofar as possible, with every surgical procedure.”3

Mechanism of Action

Local anesthetics block cell-membrane sodium channels on neurons, thereby preventing the propagation of action potentials and transmission of pain signals. Local anesthetics differ in their chemical structures and can broadly be categorized into amides (e.g., lidocaine, bupivacaine, mepivacaine, ropivacaine) and esters (e.g., procaine, tetracaine). The chemical structure influences the solubility and metabolism of the drug. The 2 most commonly used local anesthetics in veterinary medicine are lidocaine (rapid onset to maximum effect; 1 to 2 hours’ duration of action) and bupivacaine (slower time to maximum effect; up to 8 hours’ duration unless formulated for extended release). Both lidocaine and bupivacaine are metabolized by the liver.5

3. Epstein ME, Rodanm I, Griffenhagen G, et al. 2015 AAHA/AAFP pain management guidelines for dogs and cats. J Feline Med Surg. 2015;17(3):251-272.

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