• After 24 hours, recalculate the total morphine requirement: the new 24-hour dose is the total of all the doses given in the previous 24 hours.
• However, care should be taken when calculating morphine requirements for people who are pain-free at rest but have pain on movement. If all the analgesia for this incident pain is incorporated into the new morphine dose, the person is likely to be excessively sedated at rest or possibly opioid toxic. CKS therefore recommends that incident pain doses are excluded when calculating the new 24-hour dose.
• If the person takes two or more as-required doses in 24 hours, increase the regular dose of morphine every 2–3 days (using the as-required amount of morphine used as a guide) until there is adequate pain relief or adverse effects prevent further dose increases:
• Increases of 30–50% have been recommended in the literature. However, expert feedback suggests that it may be safer to limit increases to 30% in primary care to avoid toxicity (especially at higher doses). A report from the National Patient Safety Agency advises ensuring that where a dose increase is intended, the calculated dose is safe for the person (for example, for oral morphine in adults, not normally more than 50% higher than the previous dose).
• Immediate-release morphine:
• If the total 24-hour dose is 90 mg (6 x 10 mg regular doses + 3 x 10 mg as-required doses), the new 4-hourly dose would be 15 mg.
• Once the pain is controlled and a stable 24-hour requirement of morphine is established, the daily dose can be switched to a modified-release preparation in a single daily dose, or in two divided doses.
• Modified-release morphine:
• For a 12-hourly modified-release preparation (Morphgesic^® SR tablets, MST Continus^® tablets or suspension, Zomorph^® capsules), divide the total 24-hour dose of morphine by two. For example, if the total 24-hour dose is 120 mg (2 x 40 mg regular modified-release doses + 4 x 10 mg as-required doses), the new 12-hourly modified-release dose would be 60 mg.
• For a 24-hourly modified-release preparation (MXL^® capsules), the dose is equivalent to the total 24-hour dose of morphine.
• If switching from regular immediate-release to modified-release morphine, give the first dose of modified-release morphine 4 hours after the last dose of immediate-release morphine (and discontinue the immediate-release preparation).
• Because the pharmacokinetic profiles of modified-release products differ, and differences in appearance may be confusing for people, it is best to keep the person on the same brand of modified-release morphine.
• Continue to provide immediate-release morphine tablets or solution for as-required treatment of breakthrough pain.

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