Pain in Cancer

Pain In Cancer

Occurs in 75% of patients

Aetiology

1. Cancer

2. Treatment

3. Comorbidities

Management

From University of Bristol teaching¹²

1. Pain History – establish “total pain”

a. Biological (SOCRATES)

b. Psychological

c. Social

d. Spiritual

2. Examination

3. Diagnosis

4. Management plan

5. Reassess: Sufficient? Excessive? Opiod irrelavent pain?

The WHO Analgesic Ladder

Inexpensive and 80-90% effective ³

1. Non-opioid + adjuvant

Paracetamol

NSAIDS

Anxiolytic

Tricyclic antidepressant

Steroids

Anti-spasmodics / muscle relaxants

2. Weak Opioid + 1

Codiene:

Tramadol:

(Detropropoxyphene: +paracetamol = co-proxamol, withdrawn due to suicides)

3. Strong Opioid + 1

Morphine:

• Starting Dose 10mg/4h PO. Same dose again PRN

• IV is ~2x as potent, diamorphine IV ~3x as potent

• Take total daily dose inc PRN and /6 – this is new dose

MST: Modified release 12-hour morphine. Requirement as above but /2 not 6

Diamorphine

Hydromorphone

Oxycodone

Fentanyl

Methadone

Pethidine,

(Buprenorphine)

In Addition

In opioid resistant patients consider adjuvants, Methodone, Ketamine ⁴

Opiods

Fears1,3: Drowsiness, Fearing this means “the end”, Tolerance, addiction

S/E: Constipation, N + V, Drowsiness, Dry mouth

Opioid Toxicity: Vivid dreams => hallucinations => confusion => myoclonic jerks (Pallionc: Gloucester amputation man) => respiratory depression

Worked Example

As an F1 doctor you are responsible for the care of a man on the ward with metastatic prostate cancer. As you clerk him in to your ward he mentions he has back pain and would like something to try and take the pain away. What will you prescribe for him?

Step 1 analgesia: A reasonable approach here would be to start with regular paracetamol 1g QDS PO. Regular or PRN diclofenac 50mg PO max TDS could also be given (first make sure there are no contra-indications to an NSAID such as peptic ulcers or asthma).

On the ward round the following morning, the man explains that he still has severe back pain which is not helped by the painkillers you have given him. What will you do now?

Step 2 analgesia: There are 2 options here. Either give Cocodamol 30/500 (30mg codeine plus 500mg paracetamol) 2 tablets PO QDS plus diclofenac 50mg PO PRN max TDS. Alternatively try tramadol 100mg PO QDS plus paracetamol 1g PO QDS plus diclofenac 50mg PO PRN max TDS. Here you are prescribing weak opiates so it is important to look for side effects such as nausea, vomiting and constipation. Also be aware that tramadol has the potential to cause serotonin syndrome when given with certain other drugs such as SSRIs.

One evening, a nurse calls you to see the same man who is in severe pain which is not controlled by his prescribed analgesia. What are you going to do?

Step 3 analgesia: Prescribe 10mg oramorph (liquid) or 10mg sevredol (tablet) depending on patient preference PO 4 hourly plus 10mg oramorph or sevredol PO PRN max hourly. You are now prescribing strong opiates hence he will also need an anti-emetic and laxitives. Prescribe cyclizine 50mg PRN PO max TDS or haloperidol 2.5mg PRN PO max OD as anti emetics. Also regular codanthrusate 2 capsules PO OD or docusate sodium 100mg PO BD plus senna 2tabs PO OD.

A few days later on a ward round you come to review the man's analgesia. His pain is controlled taking the regular oramorph you prescribed plus 3 PRN doses. He is also feeling sick. Calculate his new regular dose.

Regular dose = 10x6 = 60mg plus PRN dose = 10x3 = 30. Total in 24h =90mg. New dose 90mg/6 = 15mg 4 hourly. His new PRN dose is also 15mg PO max hourly. Change anti-emetics from PRN to regular and add in an extra PRN ant-emetic (haloperidol or cyclizine).

His pain is well controlled on this dose and he wants to go home. What will you do.

Before discharge you need to convert his oramorph to a slower release preparation which only needs to be taken BD. Prescribe MST SR (morphine sulphate slow release). His dose will be 90mg/2 = 45mg PO BD. MST only comes in 10mg tablets therefore round up or down eg. 40mg BD.

References

'Online Tutorial: Principles of Pain Management in Advanced Cancer' by Professor Karen Forbes
Tutorial: Prescribing in Palliative care, Karen Forbes
WHO | WHO's pain ladder. Available at:
Longmore, M., Wilkinson, I., Turmezei, T., and Cheung C., K. Oxford Handbook of Clinical medicine