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When cancer pain needs a strong painkiller, morphine by mouth is usually the first choice: a regular dose plus extra 'rescue' doses for pain that breaks through, adjusted until the pain is controlled with side effects you can live with. A laxative should be prescribed from the start, because almost everyone taking strong opioids gets constipated.
NICE CG140 (2012, updated 2016) and WHO (2018) agree on the core: oral morphine first, regular dosing with immediate-release oral morphine for rescue (WHO strong recommendation, moderate-quality evidence). NICE gives a starting schedule for adults without renal or hepatic impairment of 20 to 30 mg oral morphine a day with 5 mg immediate-release rescue doses during titration, and asks for specialist advice before strong opioids in moderate to severe renal or hepatic impairment. ASCO 2023 starts PRN at the lowest dose with early assessment and frequent titration; the Australian guideline (2025) adds ASCO's minimum dose increase of 25 to 50% and NCCN's practice of folding the previous 24 hours of rescue doses into the regular dose.
Rescue doses are where the sources differ most in their numbers: WHO suggests 50 to 100% of the regular 4-hourly dose; the Australian guideline, citing ASCO 2022, 5 to 20% of the daily regular dose, up to hourly; NICE gives a fixed 5 mg during titration and says not to use fast-acting fentanyl as first-line rescue. Every patient starting a strong opioid should be prescribed a regular laxative (NICE 1.1.18); NICE says to optimise laxatives before switching opioids, and points to naldemedine and naloxegol appraisals for constipation that persists despite laxatives. Nausea and drowsiness at the start or after a dose rise are usually transient; persistent central nervous system effects call for dose reduction if pain is controlled or a switch if it is not.
The ESMO 2018 guideline, which the Australian guideline draws on heavily, could not be read directly.
Why: Fear that morphine is addictive or means the end is near stops many people taking enough to control their pain.
“When offering pain treatment with strong opioids to a patient with advanced and progressive disease, ask them about concerns such as:”
NICE 2012 · Not graded (NICE 1.1.1)
Why: Most of the work of pain control happens at home, and people need to know what to do when pain breaks through at night.
“Provide verbal and written information on strong opioid treatment to patients and carers, including the following:”
NICE 2012 · Not graded (NICE 1.1.2)
Why: Morphine by mouth works for most people, is cheap and widely available, and a fast-acting rescue dose covers pain between regular doses.
“Regularly-dosed immediate-release oral morphine, or regularly-dosed slow-release morphine, should be used to maintain effective and safe pain relief whenever oral dosing is possible. With either formulation, immediate-release oral morphine should be used as rescue medicine.”
World Health Organization 2018 · Strong recommendation; moderate-quality evidence
Why: A low starting dose with rescue doses lets the right dose be found safely within a few days.
“For patients with no renal or hepatic comorbidities, offer a typical total daily starting dose schedule of 20 mg to 30 mg of oral morphine (for example, 10 mg to 15 mg oral sustained-release morphine twice daily), plus 5 mg oral immediate-release morphine for rescue doses during the titration phase.”
NICE 2012 · Not graded (NICE 1.1.5)
Why: Morphine and its breakdown products build up when the kidneys or liver are failing, which can cause drowsiness, confusion and twitching.
“Seek specialist advice before prescribing strong opioids for patients with moderate to severe renal or hepatic impairment.”
NICE 2012 · Not graded (NICE 1.1.7)
Why: The right dose is the one that controls the pain with side effects you can live with, and it differs from person to person.
“Adjust the dose until a good balance exists between acceptable pain control and side effects. If this balance is not reached after a few dose adjustments, seek specialist advice. Offer patients frequent review, particularly in the titration phase.”
NICE 2012 · Not graded (NICE 1.1.6)
Why: The rescue doses a person needed show how much more regular opioid they need.
“Regular dose of opioid may be increased to incorporate the rescue doses taken in previous 24 h (NCCN), then reassess pain severity and adverse effects within 48 h. (Consensus)”
Asia-Pacific Journal of Clinical Oncology 2025 · Consensus (NCCN source)
Why: Oral morphine works for most breakthrough pain; fast-acting fentanyl products cost much more and are kept for when morphine does not work.
“Do not offer fast-acting fentanyl as first-line rescue medication.”
NICE 2012 · Not graded (NICE 1.1.15)
Why: Constipation affects nearly everyone on strong opioids and does not wear off with time.
“Prescribe laxative treatment (to be taken regularly at an effective dose) for all patients starting strong opioids.”
NICE 2012 · Not graded (NICE 1.1.18)
Why: Changing the laxative usually works and keeps the pain control that has been found; antagonists such as naldemedine or naloxegol block opioids in the gut only.
“Optimise laxative treatment for managing constipation before considering switching strong opioids.”
NICE 2012 · Not graded (NICE 1.1.20)
Why: Knowing the early side effects usually fade helps people keep taking the medicine; drowsiness can affect driving.
“If nausea persists, prescribe and optimise anti-emetic treatment before considering switching strong opioids.”
NICE 2012 · Not graded (NICE 1.1.23)
Why: These are signs of too much opioid for this person; lowering the dose or changing the drug usually clears them.
“consider dose reduction if pain is controlled or”
NICE 2012 · Not graded (NICE 1.1.25)
Why: A full reversing dose in someone on long-term opioids brings on severe pain and withdrawal; small doses reverse the danger and keep some pain relief.
“If respiratory rate ≤ 8/min and the person is unrousable, use the appropriate dose of naloxone in frequent small doses with the aim to improve consciousness without worsening pain (diluting ampoule to 10 mL). (ESMO, NCCN)”
Asia-Pacific Journal of Clinical Oncology 2025 · Adopted from ESMO and NCCN
How care is usually carried out, read from the guidelines and standards cited. Your own team's protocol and their judgement come first; this page is for understanding it, not for doing it yourself.
Oral morphine first, regular dosing plus immediate-release oral morphine as rescue (WHO 2018, strong recommendation, moderate-quality evidence; NICE CG140), titrated with frequent review, with a regular laxative from day one (NICE CG140; Australian guideline 2025 citing ESMO, NICE and NCCN). The starting dose for adults without renal or hepatic impairment is NICE's 20 to 30 mg a day; ASCO 2023 starts as needed at the lowest effective dose. The size of the rescue dose differs between sources and is stated side by side: WHO 50 to 100% of the 4-hourly dose; ASCO 2022 (via the Australian guideline) 5 to 20% of the daily dose, up to hourly; NICE a fixed 5 mg while titrating. None of these rests on strong trial evidence: WHO calls its rescue statement best practice and found one small trial.
World Health Organization 2018 · NICE 2012 · Asia-Pacific Journal of Clinical Oncology 2025 · ASCO (Journal of Clinical Oncology) 2023
Where it differs: Starts immediate-release opioid only as needed (PRN) at the lowest dose, with early assessment and frequent titration, adding a long-acting opioid once three or four doses a day are needed consistently.
Evidence: ASCO 2023 recommends PRN initiation at the lowest possible dose; the Australian guideline applies it to intermittent pain and adds NCCN's threshold of 3 to 4 doses a day. NICE and WHO start regular dosing. No trial comparing the two starts was found in the sources read.
ASCO (Journal of Clinical Oncology) 2023 · Asia-Pacific Journal of Clinical Oncology 2025
Where it differs: Sets the rescue dose at 5 to 20% of the daily regular morphine-equivalent dose, available hourly, with advice to seek help if three doses in a row have not worked (Australian guideline, citing ASCO 2022 and NCCN). WHO suggests 50 to 100% of the regular 4-hourly dose, which is roughly 8 to 17% of the daily dose.
Evidence: Consensus in all sources. WHO found one small trial (68 patients) on breakthrough pain and could not make a recommendation, issuing a best practice statement instead.
Asia-Pacific Journal of Clinical Oncology 2025 · World Health Organization 2018
Where it differs: Starts with a fentanyl or buprenorphine patch instead of oral morphine.
Evidence: NICE does not routinely offer patches as first-line maintenance where oral opioids are suitable, and considers them where oral opioids are not suitable and pain is stable. The Australian guideline notes a reduced risk of constipation with transdermal preparations and that they suit stable pain only, because of slow onset and long action.
Where it differs: Where constipation persists despite stimulant and softening laxatives, switches to a less constipating opioid, to oxycodone combined with naloxone (below its maximum dose), or uses methylnaltrexone short term in palliative care.
Evidence: Adopted by the Australian guideline from ESMO, NCCN and NICE; NICE refers to its technology appraisals of naldemedine (TA651) and naloxegol (TA345) for people who have had laxatives.
| Recommendation | Grade, as printed | Source |
|---|---|---|
| NSAIDs, paracetamol and opioids, alone or together, at the start of cancer pain management | Strong recommendation; low-quality evidence | World Health Organization 2018 |
| Any opioid may be considered for maintenance of pain relief | Strong recommendation; low-quality evidence | World Health Organization 2018 |
| Regular oral morphine (immediate or slow release) with immediate-release oral morphine as rescue | Strong recommendation; moderate-quality evidence | World Health Organization 2018 |
| Breakthrough pain treated with an immediate-release opioid rescue medicine “Breakthrough pain should be treated with a rescue medicine, which should be an opioid such as morphine in its immediate-release formulation.” | Best Practice statement | World Health Organization 2018 |
| Subcutaneous rather than intramuscular route when oral or transdermal routes are not possible “When oral or transdermal routes are not possible for administration of opioids, the subcutaneous route is preferred over intramuscular injection, as this route is less painful for the patient.” | Best Practice statement | World Health Organization 2018 |
| Taper gradually if physical dependence has developed “If a patient has developed physical dependence on opioids over the course of the management of their pain, opioid dosages should be decreased gradually to avoid withdrawal symptoms.” | Best Practice statement | World Health Organization 2018 |
| A regular laxative for all patients starting strong opioids | Not graded (NICE does not grade recommendations) | NICE 2012 |
| Laxatives routinely for prophylaxis and management of opioid-induced constipation “Laxatives must be routinely prescribed for both the prophylaxis and the management of opioid‐induced constipation (ESMO, NICE, NCCN)” | Adopted from ESMO, NICE and NCCN (strength as in the source guidelines, not printed beside the recommendation) | Asia-Pacific Journal of Clinical Oncology 2025 |
Shares Fentanyl (transmucosal, for breakthrough cancer pain), Methylnaltrexone, Cancer pain management, Early integrated palliative care.
Shares Cancer pain management, Early integrated palliative care.
Shares Fentanyl (transmucosal, for breakthrough cancer pain), Methylnaltrexone, Early integrated palliative care.
Shares Early integrated palliative care.
Shares Fentanyl (transmucosal, for breakthrough cancer pain), Cancer pain management.
Shares Early integrated palliative care.
Shares Early integrated palliative care.
Shares Cancer pain management, Early integrated palliative care.