ANSWERS

1. Define analgesia.
   Insensibility to pain; especially the relief of pain without causing unconsciousness.
2. Why are analgesic drugs often administered as part of a patient's premedication?
   An animal is usually anaesthetised for the purpose of enabling surgery in a humane manner. Surgery of any kind is generally painful in varying degrees, and therefore analgesia promotes a more comfortable induction and recovery for the patient. Other drugs used in anaesthesia (sedatives, induction agents and volatile gases) may possess poor analgesic properties, thus indicating a need for additional pain relief.
3. There are 2 main analgesic drug groups; state them, giving 2 common examples of each that are used in veterinary practice.
   • Narcotic analgesics (opioids) - pethidine and morphine.
   • Non-steroidal anti-inflammatory drugs (NSAIDS) - aspirin and ketoprofen.
4. Most narcotic analgesics are schedule 2 controlled drugs; which regulations control their purchase and use?
   The Misuse of Drugs Act 1971 and the Misuse of Drugs Regulations 1985.
5. In addition to pethidine and morphine, list 3 other narcotic analgesics.
   • Fentanyl (Sublimaze).
   • Papaveretum (Omnopen).
   • Buprenorphine (Vetergesic)
     NB. Fentanyl is not used in cats.
     
     
6. Why are narcotic analgesics unpredictable?
   They possess both stimulant and depressant actions on the central nervous system. The result depends upon the dose, species and presence or absence of pain.
7. What adverse effects may arise in a patient stimulated by the administration of a narcotic analgesic?
   • Defecation.
   • Vomiting.
8. What serious side effect is unavoidably linked with analgesia, and particularly narcotic drugs?
   Respiratory depression. The cough reflex is also suppressed which may prove problematic.
9. Why is pethidine preferred in cases of moderate pain over morphine?
   Pethidine does not cause excitement reactions, and defecation and vomiting are rare. Its mild anticholinergic properties and resultant spasmolytic effect make it a useful drug for patients suffering intestinal pain.
10. List 3 conditions in which the administration of morphine would be contraindicated.
    • Acute pancreatitis.
    • Biliary obstruction.
    • Head injuries (they may increase intra-cranial pressure).
11. List 5 conditions in which the use of opioids may be indicated.
    • Opioids are the preferred treatment in cases of severe pain following trauma or surgery. Some examples are listed:
    • Fractures (but not of the skull - see Q10).
    • Thermal burns.
    • Aural ablation.
    • Cruciate repair.
    • Femoral head arthroplasty.
12. Define a partial agonist and give an example.
    A partial agonist is an antagonistic drug with sufficient agonist properties to enable its use as an analgesic. Buprenorphine (Vetergesic) is an example and is popular due to its long-lasting effect.
13. For what reasons are narcotic antagonists used?
    • To antagonise analgesia in the event of adverse side effects.
    • To antagonise analgesia post surgery for a faster recovery.
    • Reduction of respiratory depression.
    • First aid measure in the event of self-administration.
14. Give 2 examples of narcotic antagonists.
    • Naloxone (Narcan).
    • Diprenorphine (Revivon).
15. Neuroleptanalgesia provides a combination of deep sedation and analgesia by a synergistic combination of a neurolept and a narcotic analgesic; what is the purpose of the neurolept?
    To counteract the unpleasant side effects of the narcotic analgesic, particularly excitement reactions and vomiting.
    Neuroleptanalgesia is described in Revision Module 3 - Understanding the Use of Premedicant Drugs.
16. Non-steroidal anti-inflammatory drugs (NSAIDS) should not be used in cases of acute pain; when might their administration be indicated?
    • Analgesia in cases of relatively mild, chronic pain (eg. osteoarthritis, osteochondritis).
    • Post operative analgesia following on from that provided under general anaesthesia.
17. Why is accurate dosage extremely important when administering NSAIDS?
    NSAIDS may prove nephrotoxic to cats and dogs.
18. Which anaesthetic gas has analgesic properties?
    Nitrous oxide.
19. Which volatile anaesthetic has analgesic properties; and when is its use contraindicated?
    Methoxyfluorane (Metofane) provides effective, long lasting analgesia. However, it should not be used in animals receiving NSAIDS. An alternative volatile anaesthetic may be selected or the NSAIDS witheld.
20. The alpha agonists possess good analgesic properties; give 2 examples.
    • Xylazine (Rompun).
    • Medetomidine (Domitor).
21. What is meant by sequential analgesia?
    Sequential analgesia is a technique employed to reduce the adverse side-effects of analgesia; low doses of drugs are administered from groups acting at different levels on the pain pathway.
22. Why are post-operative analgesics ideally administered before recovery begins?
    Drugs such as opioids are slow acting and it may be up to 30 minutes before they take effect. It is believed that the quality and duration of pain relief is improved if analgesics are administered pre-emptively (ie. before the animal wakes up and appreciates pain).
23. List behavioural signs that may indicate that an animal is in pain.
    • Aggression.
    • Anxiety.
    • Diminished response to stimuli.
    • Cringing.
    • Huddling.
    • Panting.
    • Praying position.
    • Shivering.
    • Vocalising.
    • Wound interference.
24. List clinical signs that may indicate that an animal is in pain.
    • Anorexia.
    • Constipation.
    • Hypertension or hypotension.
    • Incontinence.
    • Lameness.
    • Pyrexia.
    • Tachycardia.
    • Tachypnoea.
25. In addition to the administration of analgesic drugs, describe some further ways in which a patient may be made more comfortable.
    • Provide plenty of soft, comfortable bedding.
    • Confinement (particularly following orthopaedic surgery).
    • Immobilisation (of a joint for example following a fracture).
    • Physiotherapy.
    • Provide assistance with grooming and cleaning.
    • Ensure that the animal receives optimal nutrition in order to promote the growth of healthy tissue.
    • Keep dressings clean and dry and prevent any wound interference.
    • Provide a warm environment for recovery.
    • Make sure that the surroundings are suitable; a shocked animal will recuperate better in a calm and quiet atmosphere, while a lively animal may appreciate lots of activity to prevent boredom.
    • Assist with urination and defecation if necessary.
    • Provide support slings for animals with walking difficulties.
    • Always treat your patients with kindness and respect, and ensure that handling is carried out gently taking particular care over any painful area.