CVMA-ACMV

Pain Control in Animals – Position Statement

April 4, 2014

Position

"The Canadian Veterinary Medical Association (CVMA) holds that veterinarians must not perform surgical procedures or treat medical conditions without the appropriate use of anesthetic and analgesic drugs. The potential for pain in animals with surgical or medical conditions must always be considered, and such pain must be prevented or treated whenever possible."

Background

Nociception and the pathophysiology of pain are well-described and the pathway is identical in all vertebrate species (1,2). Species-typical responses to pain are increasingly well-described (3−5). The capacity of animals to experience pain should not be surmised from the stoic behaviour that is typical of many species (3−5). Instead, a precautionary approach is required to practice veterinary medicine in an ethical and humane manner. Veterinarians have a professional responsibility to be able to recognize pain and distress in the species they treat and to stay current with new developments in pain management and recordkeeping (6).

In the case of surgically induced pain, successful management requires thoughtful planning of peri-operative analgesia to ensure effective pain relief is provided before, during, and after surgery. The concurrent use of two or more pharmacologic classes of analgesic drugs (opioids, alpha-2 agonists, anti-inflammatories, local anesthetics, dissociative anesthetics) generally provides more effective pain control, with fewer side-effects, than therapy with a single drug (1,2). The potential for adverse side effects, which can occur when higher doses of a single agent are used is also reduced (2,7). Local and regional analgesics and anesthetics should be incorporated into the peri-operative management plan, whenever appropriate. While sedatives (e.g., phenothiazines, benzodiazepines) and general anesthetics (e.g., thiopental, propofol, inhalants) alter the perception of pain, they do not substantially alter nociceptive processing and should not be considered analgesic drugs.

Currently, some anesthetic and analgesic drugs are licensed for use in companion animals, but fewer are licensed for use in livestock or wild animals. The CVMA recognizes that there is an urgent need to approve anesthetic and analgesic drugs for food animal species, and to provide veterinarians and producers with appropriate withdrawal times for these drugs.  There are quality assurance programs for some livestock species that prohibit the extra-label use of anesthetic and analgesic drugs. It is unlikely that the extra-label use of anesthetic and analgesic drugs in certain situations poses a significant risk to human health (i.e., young farm animals that are months away from market, or wild animals anesthetized for research or animal control purposes that are months away from legal harvest seasons).  The CVMA cannot support quality assurance programs that promote inhumane treatment of any species by prohibiting the prudent use of extra-label anesthetic and analgesic drugs.

Given the current lack of anesthetic and analgesic drugs licensed for use in livestock and wild animals, the CVMA supports the responsible extra-label use of these drugs by veterinarians to ensure the humane treatment of all species (8). The CVMA also urges federal regulators to develop programs that facilitate approval of species-appropriate anesthetic and analgesic drugs, or to exempt most of these drugs from restrictions that unintentionally promote the inhumane treatment of animals.

Nonpharmacologic methods of pain control, such as acupuncture, ultrasound, or laser therapy, physical therapy and rehabilitation, and therapeutic massage, as well as enhancing animal management, such as through weight loss programs or dietary manipulations, can be used in some cases to enhance animal comfort for painful conditions or following painful procedures, in conjunction with pharmacologically active therapies (2).

References

1. Meintjes RA.  An overview of the physiology of pain for the veterinarian. Vet J. 2012;193:344-348.

2. Dyson DH. Perioperative pain management in veterinary patients. Vet Clin North Am Small Anim Pract 2008;38:1309-1327.

3. Weary DM, Niel L, Flower FC, Fraser D. Identifying and preventing pain in animals. Appl Anim Behav Sci 2006;100:64-76.

4. Diesch TJ, Mellor DJ, Johnson CB, Lentle RG. Responsiveness to painful stimuli in anaesthetised newborn and young animals of varying neurological maturity (wallaby joeys, rat pups and lambs). ALTEX 2007;14:549-552.

5. Weber ES, 3rd. Fish analgesia: Pain, stress, fear aversion, or nociception? Vet Clin North Am Exot Anim Pract 2011;14:21-32.

6. Rollin BE.  Animal pain: What it is and why it matters. J Ethics. 2011;25:425-437.

7. AAHA/AAFP Pain Management Guidelines Task Force.  AAHA/AAFP Pain Management Guidelines for Dogs and Cats. J Amer Anim Hosp Assoc 2007;43:235-248.

8. Smith G.  Extralabel use of anesthetic and analgesic compounds in cattle. Vet Clin North Am Food Anim Pract 2013;29:29-45.

Revised July 2013