Once pain is controlled there is a choice of options for maintenance:
- Continue regular immediate release Morphine.
- Change to 12 hourly modified release Morphine.
To change from immediate release morphine to modified release Morphine, add up the amount of Morphine used in 24h and divide the 24h total dose of Morphine by 2.
E.g. Patient on 10mg immediate release Morphine 6 times in 24 hours: Total daily dose = 60mg/24h
Therefore Morphine Sulphate modified release would be: 60÷2= 30mg 12 hourly.
- Patients on modified release opioids should always have available immediate release opioid prescribedP.R.N. for episodes of breakthrough pain.
- The recommended dose of immediate release opioid (usually Morphine) prescribed P.R.N. for breakthrough pain is the equivalent of up to 1/6th of the total 24-hour opioid dose.
A patient should never be prescribed more than one modified release opioid at a time.
A patient taking Morphine Sulphate MR 30mg BD, the breakthrough dose of Morphine Sulphate IR is:
30mg + 30mg = 60mg
60mg ÷ 6 = 10mg
Therefore the breakthrough pain dose of Morphine Sulphate immediate release is 10mg P.R.N.
- If the regular dose of opioid is increased, ensure that theP.R.N. breakthrough dose is increased appropriately so that it remains 1/6th of the total daily dose of regular opioid.
- Incident pain (e.g. exacerbations of pain on movement) 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.