This advice is sourced from Dr Ros Taylor a senior palliative physician
Q. How do I decide when it is appropriate to start a patient on a strong opioid and what is best practice?
The WHO ladder recommends regular analgesia by mouth for severe cancer pain. The steps are:
- non-opioids (e.g. Paracetamol and NSAIDs)
- moderate opioids (e. g. Codeine and Tramadol)
- strong opioids (e. g. Morphine, Fentanyl and Oxycodone) until the patient is free of pain
If a full dose of a moderate opioid (step 2) is not giving 24 hour pain relief, then consider stepping up to a strong opioid. The gold standard is Morphine oral solution (10mgs/5 mls) used regularly e.g. 2.5 mgs 4 hourly and titrate as needed.
Once a steady dose is reached then convert to 12 hourly modified release e.g. MST or Zomorph. E.g. if a patient is needing 5mgs six times a day, then can covert to modified release Morphine 15mgs twice daily.
In renal failure, the safest long-acting opioid to use is transdermal Fentanyl. A conversion table can be used to convert to transdermal Fentanyl.
As renal function worsens however, it is safer to use low doses of short-acting liquid options such as low dose Oxycodone, which evidence suggests may be slightly safer than Morphine in renal failure.
Fentanyl patches are also a good option if patients are not safely swallowing, poorly compliant with oral medications or are vomiting. Fentanyl patches are changed every 72 hours and the lowest dose is 12mcg per hour which is equivalent to approximately 30mg - 40mg of Morphine per 24 hours.
Remember to prescribe a laxative and possibly an antiemetic.
It is always good to explore a patient's concerns and beliefs when starting a medicine such as Morphine.