Analgesia

Question 1

What options are there for non-pharmacological management of chronic pain? What problems might be faced if only non-pharmacological were used?

Answer 1

Hot/cold compress therapy, weight loss for OA, diet supplementation.
Take a while to become effective and impractical to provide continuous relief (e.g. Can hold compress on 24/7). They should therefore only really be considered as adjuvants to pharmacological analgesia

Question 2

Name the 5 major side effects of administration of NSAIDs

Answer 2

1) GI effects (ulceration, V, D)
2) Renal damage (reduced renal blood flow during hypotension)
3) Elevated liver enzymes (ALT, ALKP)
4) Hypertension (increased sodium and water retention, from kidney dysfunction)
5) Blood clotting (prolonged clotting times. Only really an issue if patient is having surgery)

Question 3

What are the risk factors for the development of adverse side effects when an animal is on NSAIDs?

Answer 3

Middle aged/old, concurrent disease(CV, GI, hepatic or renal), moderate to severe systemic disease in other body systems, multiple drug therapies for concurrent disease, history of adverse events from previous NSAID use.

Question 4

Name the 3 opioid receptors and list the opioids that bind to them

Answer 4

Mu - methadone, fentanyl and morphine (full agonist), buprenorphine (partial agonist)
Kappa - butorphanol
Delta - none

Question 5

Which opioid would be suitable for a patient recovering from surgery, experiencing moderate to severe pain. Explain your answer.

Answer 5

Methadone as medium duration of action (3-4hrs), and a full mu agonist. More efficacious than buprenorphine, buprenorphine unable to manage moderate to severe pain. Less frequent dosing than pethidine or butorphanol (90 mins). Could CRI of fentanyl, or morphine if methadone is unable to provide adequate analgesia.

Question 6

Define potency and efficacy, in relation to the administration of opioids.

Answer 6

Potency: the concentration of a drug required to elicit half the maximum biological response of the agonist.
Efficacy: the maximum possible biological effect that a drug or receptor ligand can achieve following binding of a receptor.