Pain management in palliative care

Question 1

Describe nociceptive, neuropathic and incident pain.

Answer 1

Nociceptive from nerve ending stimulation. Neuropathic from anywhere in nervous system by stimulation or dysfunction. Incident - expected or exacerbated by event (eg. moving)

Question 2

Apart from a description of the pain, what are 3 topics to consider when taking a pain history?

Answer 2

Associated symptoms; psychosocial (anxiety/depression); illicit drug use (tolerance and drug seeking).

Question 3

What are 4 mechanisms for a cancer to cause pain?

Answer 3

Direct invasion; oedema in a tight area (eg. CNS, liver); paraneoplastic (eg. high calcium); obstruction of a hollow viscus.

Question 4

What are 2 mechanisms each for radiotherapy and chemotherapy to cause pain?

Answer 4

Raido: local inflammation, neuropathy. Chemo: mucositis (esp GIT); neuropathy.

Question 5

What are 2 non-opioid primary analgesics? What are some side effects to consider?

Answer 5

Paracetamol and NSAIDs. NSAIDs: PUD, renal impairment, fluid retention.

Question 6

What are 4 factors to consider in deciding which opiate to use in pain management?

Answer 6

Side effects; metabolism of drug; previous opiates used (tolerated?); administration route.

Question 7

What are the common ‘safe’ side effects of opiates? What are some dangerous ones?

Answer 7

Common: constipation, nausea/vomiting, itch, sweating. Risky: drowsiness, confusion, myoclonic jerks.

Question 8

What are 4 forms of morphine and their duration of action? What is the ratio of subcut to oral morphine?

Answer 8

Short: Ordine and severdol 3-4hrs. Long: MS contin (12hr) and kapamel (24hr).
1mg s/c = 3mg oral.

Question 9

What are 3 forms of oxycodone and their duration of action? What is the conversion ratio to morphine?

Answer 9

Short: endone, oxynorm 4-6hrs. Long: oxycontin (in targin).

1mg oxycodone = 1.5mg morphine.

Question 10

What are 2 forms of hydromorphone and their duration of action? What is the conversion ratio to morphine?

Answer 10

Short: dilaudid 2-3hrs. Long: jurnista 24hrs.

1mg hydromorphone = 5-6mg morphine.

Question 11

In what form is buprenorphine used? Duration and smallest dose? Conversion ratio to morphine.

Answer 11

Long patch ‘Norspan’ for 7 days. Smallest dose is 5mg per day = 15mg morphine per day.
Takes time to titrate up.

Question 12

Why is methodone different to other opioids? What implications does this have?

Answer 12

Also blocks NMDA receptor to reduce pain sensitivity. Used as add-on or replacement, but only in specialist settings. No consisent conversion ratio - start slowly.

Question 13

Apart from methodone, what other drug blocks NMDA receptors? What is it used for?

Answer 13

Ketamine. Used as an anaesthetic. No evidence for use in chronic pain, back up maybe.

Question 14

What are 3 antidepressants that may be used as adjuvants in pain management?

Answer 14

Amitriptyline, nortriptyline (tricyclics) and daloxitene (SNRI)

Question 15

What are 3 anticonvulsants that may be used as adjuvants in pain management?

Answer 15

Carbamazepine (old, esp for trigeminal neuralgia). Gabapentin and pregabalin (esp for neuropathic pain)

Question 16

In what general dosing pattern should opioids be prescribed? Long or short acting preferred?

Answer 16

Want long-acting baseline analgesia and breakthrough analgesia as needed. Each breakthrough dose = 1/6 of total 24 dose.