Opiates in palliative care

Opiates are used in step 2 and step 3 on the "pain ladder".

• step 2: weak opioids (for moderate pain) e.g. codeine, dihydrocodeine, tramadol
  • these opioids have low potency but can be a useful second step for patients with moderate pain. There is some overlap in 'analgesic effect' between the higher doses of weak opioids and lower doses of strong opioids
  • it is seldom useful to change from one preparation to another (unless to alter side effects). If regular doses do not provide adequate analgesia, move up the ladder to step 3
  • compound preparations of paracetamol and weak opioids may be useful. Only preparations with higher doses of opioids (codeine 30mg, dihydrocodeine 20-30mg) should be used, as the lower strength preparations produce opioid side effects with little analgesia
    
    
• step 3: strong opioids (for moderate to severe pain)
  • first line: Morphine remains the drug of choice
    • gain Control of Pain
      • 'Immediate' release morphine (elixir or tablets) gives greatest flexibility for dose titration
      • starting dose 5-10mg morphine 4 hrly i.e. 6 x daily, (5mg for opioid naive patients; in the elderly or those with renal impairment use smaller doses e.g. 2.5mg four-hourly, with close monitoring). Additional prn doses at the same starting dose may be prescribed
      • titrate the dose to achieve pain relief by 30 - 50% increments in dose every 2-3 days or sooner if necessary - the latest update of the West Midlands guidance states that, if required, increases in analgesia should be done daily ".. titrate the dose to achieve pain relief by increasing in 30 - 50% increments per day.." (2)
        • reassess pain control daily
        • a 'log' of treatment kept by patients and carers is helpful in titration
      • there is no 'maximum' dose if pain is morphine responsive
      • specialist palliative care advice should be sought in the following circumstances:
        • rapidly escalating dose of morphine
        • morphine exceeds 300mg in 24 hours
        • if the patient develops adverse effects e.g. opioid toxicity (signs are respiratory depression, increasing drowsiness, confusion, myoclonic jerks)
      • in patients with less severe pain, or where circumstances dictate, morphine may be initiated as a modified release preparation at the appropriate dose
      • always prescribe a laxative when initiating opioid and continue to review bowel habit
        
        
    • maintenance
      • once pain is controlled there is a choice of options for maintenance:
        • continue regular immediate release morphine
        • change to 12 hourly modified release morphine
      • patients on modified release opioids should always have available immediate release opioid prescribed p.r.n. for episodes of breakthrough pain.
      • recommended dose of normal release opioid (usually morphine) for breakthrough pain is the equivalent of up to one sixth of the total 24-hour opioid dose
      • if the regular dose of opioid is increased, ensure that the breakthrough dose is increased appropriately
      • incident pain may require faster acting analgesia
      • ensure patients and their carers understand the use of the opioids they are taking and that doses are reviewed regularly
        
        
    • if further pain develops
      • reassess cause of pain and treat appropriately
      • if there is consistent need for frequent breakthrough analgesia, and the pain is opioid sensitive, increase the total daily opioid dose by 30 -50% and reassess
      • if the proposed dose increase is greater than 30 -50% seek advice from specialist palliative care

When prescribing opiates:

• a laxative is essential in most cases
• an anti-emetic may be needed for the first 3-7 days
• any initial sedation or confusion usually settles within 3-5 days (if not, change drug or seek advice)
• supplementary analgesia for breakthrough pain should always be available
• there is no upper dose limit but check why pain is uncontrolled
• co-analgesics (NSAID's, steroids, anti-depressants etc) may be needed especially in neuropathic and bone pain
• ring Hospice staff or Macmillan nurses for help with medication in palliative care. They are much more familiar with them than the GP is likely to be

NHS tool to calculate estimated dose equivalences of oral morphine to other oral opioids

Reference:

• (1) West Midlands Palliative Care Physicians (2007). Palliative care - guidelines for the use of drugs in symptom control.
• (2) West Midlands Palliative Care Physicians (2012). Palliative care - guidelines for the use of drugs in symptom control.