Pain in Palliative Care

Katie Dumble

Definition of Pain

‘An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such

damage’ (International Association for the Study of Pain)

‘whatever the experiencing person says it is, existing whenever he says it does’ (Margo McCaffrey ,1968)

WHO Pain Ladder

Analgesic DrugsRoute of Admin Major Side Effects Other problems

Paracetamol Oral/IV Hepatotoxicity

NSAIDSe.g. Ibuprofen

Oral GI- bleeding, dyspepsia, abdo pain, diarrhoea.Renal impairment

Opiatese.g. MorphineCodeine

Oral, Rectal, SC (syringe driver), IM, IV, PCA,Epidural

ConstipationRespiratory DepressionSedationNausea

Physical dependence

Opioid side effects

• Constipation• Nausea and vomiting• Sedation• Vivid dreams• Hallucinations• Confusion• Myoclonic jerks• Respiratory depression

Toxicity

Drug Relative potency to Oral Morphine

Oramorph (4hourly) 1

MST (12hourly) 1

IM Morphine 2

Sc Morphine 2

Diamorphine 3

Oxycodone 2

Fentanyl 150

Hydromorphone 7.5

Tramadol 0.2

Prescribing

• Starting dose for morphine 10mg 4 hourly (2.5-5mg in frail/elderly)

• The same dose (10mg) is PRN dose (1/6th of total daily dose)

• Increase incrementally over days until patient’s pain controlled

Case 1

• Mrs K, a 50 year old lady with breast cancer and pain from bone metastases

• Currently on Cocodamol 30/500, 2 tablets, QDS.

• Pain not controlled• What should you do?

Case 1 Answers

• Pain not controlled so need to go up WHO pain ladder

• Add in strong opiate.• Starting dose Oramorph 10mg 4hourly and

PRN Oramorph 10mg.• Consider antiemetics and laxatives• Titrate dose up gradually until pain controlled

Prescribing

• When daily morphine requirements are stable can convert 4hourly morphine into modified release form

• Same total daily dose given but split into 2 doses rather than 6.

• I.e Oramorph 10mg 4hourly is equivalent to MST 30mg 12hourly.

• PRN dose remains the same (10mg Oramorph)

Case 2

• Mrs K’s pain is finally controlled with Oramorph 30mg. She does not like taking so many tablets.

• What do you do?

Case 2 answer

• Change to modified release morphine e.g. MST.

• Dose is total daily amount of oramorph split into 2 doses 12 hours apart

• MST 90mg 12hourly and PRN Oramorph 30mg

Prescribing if patient unable/unwilling to swallow

• IM morphine – divide total daily dose of oral morphine by 2. Then split between 6 daily doses (4hourly).– E.g Oramorph 10mg 4hourly is equivalent to IM Morphine

sulphate 5mg 4hourly.

• IM Diamorphine- better for palliative care patients because more soluble so given in smaller volume than morphine sulphate.– Divide total daily dose by 3 and split into 6 daily doses.– E.g. Oramorph 15mg 4hourly becomes Diamorphine 5mg

4hourly. (Comes in 5, 10, 30,100 and 500mg ampules)

Case 3

• Mrs K becomes more weak and unwell, she can no longer swallow, but she is distressed by her pain. She is still prescribed MST 90mg 12hourly and PRN Oramorph 30mg.

• What should you do?

Case 3 Answer

• Needs parenteral route for pain relief• IM Morphine sulphate 15mg 4hourly (90x2/2

into 6 doses) and PRN IM Morphine sulphate 15mg

Or• IM Diamorphine 10mg 4hourly (90x2/3 into 6

daily doses) and PRN IM Diamorphine 10mg

Syringe drivers

• Diamorphine can also be given sc so can be put in a syringe driver

• Divide total daily dose oral morphine by 3• E.g. Oramorph 10mg 4hourly is equivalent to

20mg Diamorphine over 24hours in syringe driver.

Case 4

• Mrs K is cachetic and the regular IM injections are difficult to do. She is currently prescribed IM diamorphine 10mg 4hourly and PRN Diamorphine 10mg.

• What should you do?

Case 4 answer

• Set up a syringe driver• Total daily dose of diamorphine put into

syringe driver and infused over 24hours.• Diamorphine 60mg over 24hours in syringe

driver (10x6)• PRN Diamorphine 10mg IM• Consider adding any other necessary drugs to

syringe driver e.g. Antiemetics.