Canis ISSN: 2398-2942

Analgesia: overview

Contributor(s): Prof Stephen Greene, B D X Lascelles, Jo Murrell, Sheilah Robertson

Introduction

Why control pain?

  • It causes suffering. The primary duty of veterinary surgeons is to relieve suffering of animals in their care.
  • It causes anorexia, catabolism and a stress response. These all result in delayed wound healing.
  • It results in prolonged recoveries, longer recumbencies and a greater risk of post-operative complications.
  • It can cause ineffective ventilation leading to hypoxia or acidosis.
  • It may lead to self-mutilation and interference with wounds.
  • It may result in chronic pain.

Considerations of providing analgesia

  • The following signs may indicate the dog is in pain Pain: assessment :
    • Anorexia.
    • Dullness and depression.
    • Whining or howling.
    • Restlessness, being unable to settle, or sitting in unnatural positions.
    • Self-mutilation or chewing at wounded area.
    • Tachypnea, tachycardia, hypertension.
    • Aggression or unresponsiveness.
    • Resentment of gentle palpation of wound.
  • An injury or surgical procedure that would be painful in a human can be assumed to be painful in a dog. If in doubt, administer a moderate dose of analgesic and assess response.
  • Pain is much more difficult to control once it is established due to a combination of peripheral and central hypersensitivity ('wind-up'). Therefore post-surgical pain can be minimized by preventing the nociceptive input from entering the spinal cord that facilitates this wind-up mechanism. This can be achieved by the use of pre-emptive analgesia Pain: management.
  • The use of balanced analgesia, ie combining more than one class of analgesic agent, eg opioid + NSAID reduces the total amount of any one analgesic required and thus reduces the risk of unwanted side effects.

Analgesic drugs

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Hansen B (2008) Analgesia for the critically ill dog or cat: an update. Vet Clin North Am Small Anim Pract 38 (6), 1353-1363 PubMed.
  • Mathews K A (2008) Pain management for the pregnant, lactating, and neonatal to pediatric cat and dog. Vet Clin North Am Small Anim Pract 38 (6), 1291-1308 PubMed.
  • Woodward T M (2008) Pain management and regional anesthesia for the dental patient. Top Companion Anim Med 23 (2), 106-114 PubMed.
  • Capner C A, Lascelles B D, Waterman-Pearson A E (1999) Current British veterinary attitudes to perioperative analgesia for dogs.​ Vet Rec 145 (4), 95-99 PubMed.
  • Carroll G L (1999) Analgesics and pain. Vet Clin North Am Small Anim Pract 29 (3), 701-717 PubMed.
  • Johnson C (1999) Chemical restraint in the dog and cat. In Practice 21 (3), 111-118 VetMedResource.
  • Taylor P M (1999) Newer analgesics. Nonsteroid antiinflammatory drugs, opioids, and combinations. Vet Clin North Am Small Anim Pract 29 (3), 719-735 PubMed.
  • Torske K E, Dyson D H, Pettifer G (1998) End-tidal halothane concentration and post operative analgesia requirements in dogs - a comparison between intravenous oxymorphone and epidural bupivicaine alone and in combination with oxymorphone. Can Vet J 39 (6), 361-369 PubMed.

Other sources of information

  • American College of Veterinary Anesthesiologists' (1998) Position paper on: The treatment of pain in animals. JAVMA 213 (5), 628-630.


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