Analgesia for chronic non-cancer pain

ASSESSMENT OF CHRONIC NON-CANCER PAIN

A biopsychosocial assessment is necessary to inform effective pain management.

Ascertain the aetiology and perpetuating factors and manage accordingly. Note that there may be overlap between different aetiologies, and condition-specific pain management may be required.

Ascertain the patient’s beliefs about their pain and hopes of care. Common issues to address are:

  • Idealised nature of reality, e.g. that life must be pain-free.
  • That pain means exercise and physical activity must be avoided.
  • Catastrophic thinking regarding the pain.
  • A need to be unwell to be cared for by others.
  • Fear of work and responsibility, for various reasons.
  • Stigma, with denial of mental illness or interpersonal conflict.

Social stressors, trauma, interpersonal conflict or violence may predispose to and perpetuate chronic pain.

GENERAL AND SUPPORTIVE MEASURES

Patients with chronic pain should be treated with a biopsychosocial approach, according to findings of a comprehensive assessment. Note that those with greater subjective pain complaints may also be at higher risk of an opioid use disorder.

  • Validate the pain experienced and manage with empathy.
  • Educate regarding the cause of pain, prognosis (including that pain may not be fully relieved), and realistic expectations regarding pain reduction.
  • Establish goals of care with the patient and select a measure of effectiveness e.g. Pain, Enjoyment and General Activity (PEG) scale, http://www.med.umich.edu/1info/FHP/practiceguides/pain/PEG.Scale.12.2016.pdf
  • Treat the underlying physical cause of pain. Refer for specialist care (e.g. rheumatologist, orthopaedic surgeon) where necessary.
  • Treat underlying or comorbid mental illness.
  • Manage substance use, refer to SANCA/ rehabilitative services.
  • Encourage physical activity; refer to Physiotherapy and Occupational Therapy (OT).
  • Address self-esteem, motivation, daily function, and social skills; refer to OT.
  • Address social stressors and interpersonal conflicts; refer to social worker, counselling services, psychologist, social welfare organisations, NGOs (e.g. FAMSA, http://famsa.org.za, or if there is domestic violence, POWA, https://www.powa.co.za)

LoEIII [1]

MEDICINE TREATMENT

Paracetamol, ibuprofen and tramadol may be used alone or in combination according to the severity of the pain.

Mild/moderate pain:

  • Paracetamol, oral, 1 g 4–6 hourly when required.
    • Maximum dose: 15 mg/kg/dose.
    • Maximum daily dose: 4 g in 24 hours.

  • NSAID, e.g.: LoEI [2]
    • Ibuprofen, oral, 400 mg 8 hourly with meals.
      • May be used in combination with paracetamol or opioids.

CAUTION

  • Avoid long-term use of NSAIDs (e.g. ibuprofen) as they are associated with an increased risk of arterial thrombosis, renal impairment and gastrointestinal bleeding.
  • Concomitant use of more than one oral NSAID has no additional clinical benefit and only increases toxicity.
  • Use of all NSAIDs is associated with increased risks of gastrointestinal bleeding, renal dysfunction, and cardiovascular events (stroke and myocardial infarction).
  • NSAIDs should be used judiciously at the lowest effective dose for the shortest duration. Explore and manage exacerbating factors for pain. See Chronic pain.
  • Do not use NSAID in pregnancy or while breastfeeding.

In high-risk patients: i.e. patients > 65 years of age, or with a history of peptic ulcer disease, or on concomitant warfarin, aspirin or corticosteroids:

LoEIII [3]

ADD

  • PPI, e.g.:
    • Lansoprazole, oral, 30 mg daily.

Severe pain:

  • Tramadol, oral, 50–100 mg 4–6 hourly.
    • Warn patient of adverse effects and addiction potential. Advise not to operate machinery/drive initially and after dosage increases.
    • Evaluate response to treatment using a rating scale at 2 weeks, and every following 4 weeks: taper and stop tramadol if not reducing pain.
    • In patients with uncontrolled pain the dose can be increased to a maximum of 100 mg (2 x 50 mg) 6 hourly.
    • Improved effect when given with paracetamol.

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CAUTION

  • Tramadol causes respiratory depression and may be fatal in overdose.
  • Avoid concurrent prescribing of opioid pain medication, benzodiazepines or other respiratory depressants.
  • After a period of no treatment, re-initiate at 25 mg. Treat overdose as in Opioid poisoning.
  • Avoid use in those at high risk of opioid addiction (a personal or family history of any substance use disorder, comorbid mental illness, high levels of subjective pain and younger people).
  • Inhibits reuptake of noradrenaline and serotonin – increases risk of seizures, of serotonin syndrome, and mania or hypomania. Avoid use in at-risk groups (e.g. epilepsy, head injury, if taking antidepressants, bipolar disorder). Educate the patient, optimise treatment of primary condition, avoid polypharmacy and monitor closely.
  • Other adverse effects include constipation, dry mouth, drowsiness, confusion.

LoEIII [5]

OR

  • Morphine syrup (Mist morphine), oral.
    • Starting dose: 10–15 mg (maximum 0.2 mg/kg) 4 hourly.
    • Elderly or frail patients: 2.5–5 mg oral (maximum 0.1 mg/kg) 4 hourly.
    • Increase dose by 50% every 24 hours if pain control is inadequate.
    • Reduce the dosing interval if there is regular breakthrough pain.
    • Increase the dosing interval in patients with renal or liver impairment.

When stable on morphine syrup, the morphine syrup can be changed to an equivalent dose of long- acting, slow release morphine:

  • Morphine, long-acting, oral, 12 hourly.
    • Available in tablets of 10 mg, 30 mg and 60 mg
    • Duration of action 12 hours.
    • Dose according to previous morphine syrup requirement: e.g. a patient whose pain is controlled by 6 doses of morphine syrup 10 mg per 24 hours (i.e. 60 mg morphine per day) can be converted to slow release morphine tablets, 30 mg 12 hourly, oral.
    • Maximum dose for non-cancer pain is usually 60 mg 12 hourly.

Note:

  • When morphine is used for chronic non-cancer pain, discuss potential side-effects with the patient, the maximum dose of opioids that will be prescribed and anticipated duration of treatment.
  • Avoid in patients with history of alcohol or other drug addiction, where possible.