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Strong Opioid Analgesic — Step 3 WHO Ladder Pregnancy: Regular use during pregnancy may cause fetal dependence and neonatal opioid withdrawal syndrome; administration during labour may depress neonatal respiration and an antidote for the child should be readily available. Not recommended in nursing women — morphine may be secreted in breast milk and cause respiratory depression in the infant.

Morphine (Oral)

Brand names: Oramorph (oral solution), Sevredol (immediate-release tablet), MST Continus (modified-release), MXL (modified-release)

Used in: Burns

Oral morphine is a strong opioid analgesic available in immediate-release and modified-release oral preparations, used for moderate-to-severe acute pain and as the opioid of choice for chronic cancer pain and palliative care.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 10-20 mg (5-10 ml of 10 mg/5 ml oral solution) every 4 hours
Route: Oral
Frequency: Every 4 hours
Max: 120 mg per day
Dosage can be increased under medical supervision according to the severity of the pain and the patient's previous history of analgesic requirements. Agree a treatment strategy, duration, goals and an end-of-treatment plan before starting; taper gradually when no longer required to prevent withdrawal. If pain control is inadequate, consider hyperalgesia, tolerance and progression of the underlying disease. When oral solution replaces parenteral morphine a 50-100% increase in dose is usually required for the same level of analgesia. Dose reduction may be appropriate in the elderly and in chronic hepatic disease, renal impairment, severe hypothyroidism, adrenocortical insufficiency, prostatic hypertrophy, shock, or where sedation is undesirable. PAEDIATRIC (UK SPC §4.2, age-banded — not per kg): 13-18 years 5-20 mg (2.5-10 ml) every 4 hours, maximum 120 mg/day; 6-12 years 5-10 mg (2.5-5 ml) every 4 hours, maximum 60 mg/day; 1-5 years 5 mg (2.5 ml) every 4 hours, maximum 30 mg/day; under 1 year not recommended. Verify all paediatric dosing against a children's formulary before prescribing.

Dose adjustments

Renal

Reductions in dosage may be appropriate in renal impairment (§4.2 Special populations).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to morphine or to any of the excipients
  • Respiratory depression; obstructive airways disease; acute asthma exacerbation
  • Acute hepatic disease; acute alcoholism
  • Head injury, coma, raised intracranial pressure, convulsive disorders
  • Paralytic ileus
  • Concurrent monoamine oxidase inhibitors or within two weeks of stopping them
  • Phaeochromocytoma

Side effects

  • Respiratory depression (including central sleep apnoea syndrome)
  • Nausea and vomiting
  • Constipation
  • Drowsiness / somnolence and confusional state
  • Hypotension, bradycardia or tachycardia
  • Drug tolerance, dependence and withdrawal syndrome on discontinuation

Interactions

  • Monoamine oxidase inhibitors — contraindicated concurrently or within 2 weeks of discontinuation (§4.3)
  • Phenothiazines and certain anaesthetics — may cause severe hypotension, particularly if blood volume is depleted (§4.4)
  • Benzodiazepines and other CNS depressants including alcohol — additive risk of hypotension, respiratory depression, profound sedation, coma and death (US label §7)
  • Serotonergic drugs — risk of serotonin syndrome (US label §7)

Clinical monograph

How it works

It is a full agonist at mu-opioid receptors in the central nervous system and periphery, reducing the perception of and emotional response to pain and depressing the brainstem respiratory centre.

Prescribing in practice

  • Respiratory depression is the most serious risk and is potentiated by other CNS depressants such as benzodiazepines, gabapentinoids and alcohol, so co-prescribe with caution.
  • Do not confuse or interchange immediate-release and modified-release preparations, and reduce doses in renal impairment and the elderly because the active metabolite accumulates.
  • Anticipate and treat constipation, nausea and sedation, and counsel on the risks of tolerance and dependence with prolonged use.

Monitoring

Monitor pain control, sedation level, respiratory rate and bowel function, reviewing the dose regularly and tapering rather than stopping abruptly after prolonged use.

Counselling the patient

  • This medicine can cause drowsiness, so do not drive or operate machinery until you know how it affects you.
  • Take a regular laxative, as constipation is very common.
  • Do not drink alcohol, and never take more than prescribed.

Evidence & guidelines

Oral morphine is recommended as a first-line strong opioid for cancer pain in NICE and WHO analgesic ladder guidance.

Reference: NICE NG31 (Cancer Pain); WHO Analgesic Ladder; Palliative Care Formulary (PCF6); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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