Palliative Care: Pain Control

Question 1

Explain nociceptive pain (somatic)

Answer 1

1. Nociceptive pain (somatic) e.g. metastatic bone pain. Multiplying cancer cells grow and put pressure on nociceptors. Responds well to analgesics and radiotherapy.

Question 2

Explain nociceptive pain (visceral)

Answer 2

2. Nociceptive pain (visceral) e.g. liver capsule pain; bladder spasm; bowel obstruction; pancreatic cancer. Infiltration, compression, distension of thoracic and abdominal viscera. Constant or crampy, aching, poorly localised and often referred. Responds well to OPIOIDS and HYOSCINE BUTYLBROMIDE (buscopan)

Question 3

Explain neuropathic pain

Answer 3

3. Neuropathic pain - may have ‘positive’ (dysaesthesias - abnormal nerve stimulation) or ‘negative’ (sensory/motor deficits) features. Pain resulting from damage to the nerves themselves. May be described as burning, pins and needles, numbness, or electric shocks. Can be poorly responsive to opioids - adjuvants often needed

Question 4

What are the three temporal patterns of pain?

Answer 4

• Acute pain
• Chronic pain
• Breakthrough pain

Question 5

What is breakthrough pain?

Answer 5

A transitory exacerbation of pain that occurs either spontaneously, or in relation to a
specific predictable or unpredictable trigger, despite relatively stable and adequately
controlled background pain

Question 6

How do you perform a pain history in palliative care?

Answer 6

• Site
• Onset
• Character
• Radiation
• Associated symptoms
• Timing
• Exacerbating/relieving factors
• Severity
  PLUS
  What treatments have you tried?
  What do you think is the cause?
• What do you think it means?
• How does this affect your ADLs?
• Impact on social life?
• Impact on mood - condensed psychiatric history?

Question 7

Explain the WHO analgesia ladder?

Answer 7

1. Non-opioid simple analgesia (mid-pain)
Paracetamol 500mg-1g PO/IV 6 hourly (QDS)
Ibuprofen 400-800 mg  PO TDS
\+/- adjuvant
2. Weak opioid (moderate pain)
Co-codamol 30/500 2 tabs PO QDS
Tramadol 50-100 mg PO QDS
\+/- non-opoid/adjuvant
3. Strong opioid (severe pain)
Short - acting morphine:
Oramorph 5-10 mg PO 4 hourly
Long acting morphine:
MST 10-30 mg PO BD
*starting dose of strong opioid should be based on dose of codeine or on short-acting opioid use
\+/- non-opioid/adjuvant

Question 8

What should you remember when prescribing opioids for breakthrough pain?

Answer 8

That the breakthrough dose should be equivalent to a 4 hourly dose i.e 1/6 of total daily opioid dose

Question 9

If a patient is taking MST 15 mg BD, prescribe a breakthrough dose of opioid

Answer 9

Total MST in a day = 30 mg 
Drug of choice = oramorph (fast-acting)
1/6 of daily dose of MST = 5 mg 
therefore,
Oramorph 5 mg 4 hourly PRN

Question 10

What should you write in the special instructions box of a kardex with prescribing opioids?

Answer 10

Write prescription dose in words i.e. if prescribing MST 10 mg write TEN MILLIGRAMS in special instructions box

Question 11

How do you convert oral morphine to oral oxycodone?

Answer 11

Divide morphine dose by 2

Question 12

How do you convert oral codeine dose to oral morphine dose?

Answer 12

Divide codeine dose by 10

Question 13

How do you convert oral morphine dose to subcutaneous morphine dose?

Answer 13

Divide by 2

Question 14

List common side-effects of opioids

Answer 14

• Constipation (prescribe laxatives e.g. senna/docusate)
• Nausea and vomiting (PRN anti-emetic essential)
• Sedation (usually mild - reassure)
  IMPORTANT: NOT RESPIRATORY DEPRESSION WHEN ASKED THIS - THIS IS LATE STAGE OF OPIOID INDUCED NEUROTOXICITY)

Question 15

List some rarer side-effects of opioids

Answer 15

• Pruritis
• Anaphylaxis
• Sweating
• Urinary retention
• Hyperalgesia/allodynia

Question 16

What are the side-effects of long-term opioid use?

Answer 16

• Immunosuppression

- Endocrine function effects

Question 17

Explain the progression of opioid induced neurotoxicity in terms of symptoms

Answer 17

1. Microsleeping
2. Delirium (most often hypoactivity)
3. Hallucinations and/or vivid dreams
4. Myoclonic jerks
5. Late sign = respiratory depression as sedation becomes very severe

Question 18

How is opioid induced neurotoxicity managed?

Answer 18

• Find and treat the cause
• IV fluids
• Reduce dose of opioid +/- opioid switch
• Consider naloxone only if RR <8 per min or as per regional guidelines (NOT 400 mcg STAT)
• Seek advice from specialist palliative care team
• Remember to consider other causes of observed symptoms

Question 19

Explain adjuvants used in bone pain

Answer 19

1. NSAIDs (limited in severe pain/renal and gastro SEs)
2. Steroids (dexamethasone 8 mg) - useful in pain crisis
3. Radiotherapy - high response rate
4. Bisphosphonates - reduction of skeletal events
5. Surgery - if impending pathological fracture

Question 20

Visceral pain - which adjuvants to consider in liver capsule pain (liver mets)?

Answer 20

• Corticosteroids - dexamethasone 8 mg

- Paracetamol 1 g QDS PO/IV

Question 21

Visceral pain - colic (intestinal spasm) or bladder spasm - which adjuvant to consider?

Answer 21

• Think SMOOTH MUSCLE pain

- Hyoscine butylbromide SC (buscopan) - 20 mg 4 hourly

Question 22

Visceral pain - malignant bowel obstruction - which adjuvant to consider?

Answer 22

• Corticosteroids (dexamethasone 8 mg)

Question 23

Adjuvants for neuropathic pain?

Answer 23

1. Opioid dose titration
2. Anti-convulsant e.g. pregablin 300 mg BD or TCA amitriptyline 10 mg nocte
3. TCA + anti-convulsant
4. Corticosteroid (1st line pain crisis)
5. NMDA antagonists e.g. ketamine - specialist only

Question 24

How is liver capsule/nerve compression pain managed in cancer?

Answer 24

For cancer-related pain (e.g. liver capsule pain, nerve compression):
Dexamethasone 8-16mg a day orally in 1-2 doses.