Opioid Analgesic — Weak (Prodrug) Pregnancy: Caution should be exercised during pregnancy, especially in the first trimester — a possible association with respiratory and cardiac malformations has been reported after first-trimester exposure. Regular use during pregnancy may cause dependence in the foetus with neonatal withdrawal; administration during labour may depress neonatal respiration and an antidote for the child should be readily available. Contraindicated in women during breastfeeding (§4.3): codeine may be secreted in breast milk and may cause respiratory depression in the infant.

Codeine Phosphate (Orthopaedic — Mild-Moderate Pain)

Brand names: Codeine Phosphate Tablets, Codeine Linctus

Codeine phosphate is a weak opioid used in orthopaedics for mild-to-moderate acute pain, typically as a step up from simple analgesia or in combination with paracetamol. This page covers its short-term use for musculoskeletal and post-injury pain.

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: Lowest effective dose for the shortest period of time — this SPC states NO specific milligram dose per administration for adults with mild to moderate pain (fetched product is Codeine phosphate 15 mg tablets)

Route: Oral

Frequency: Up to 4 times a day, at intervals of not less than 6 hours

Max: Maximum daily dose of codeine should not exceed 240 mg; duration of treatment for mild to moderate pain should be limited to 3 days

§4.2 'For Mild to Moderate Pain — Adults' states only: codeine should be used at the lowest effective dose for the shortest period of time; the dose may be taken up to 4 times a day at intervals of not less than 6 hours; maximum daily dose of codeine should not exceed 240 mg; duration should be limited to 3 days and if no effective pain relief is achieved the patient/carer should be advised to seek the views of a physician. IMPORTANT: the 30–60 mg every 6 hours figure in this SPC belongs to the 12–18 year age group ONLY (see paedDose) and must not be assumed to be the adult per-dose figure — the adult milligram dose was not stated in the source and has not been supplied from any other source. Elderly: dosage should be reduced. Other indications in the same SPC: dry or painful cough — adults 15–30 mg 3–4 times daily; diarrhoea — adults 30 mg three to four times daily (range 15–60 mg). Before starting, agree a treatment strategy including duration, goals and a plan for ending treatment; review the need for continued treatment frequently and taper the dose gradually on stopping to prevent withdrawal. §4.5 (interactions) was not part of the fetched bundle; §4.4 was truncated at the source-fetch limit mid-way through a statement about pethidine and possibly other opioid analgesics in patients taking an MAOI.

Paediatric dose

Route: oral

Frequency: every 6 hours when necessary

Max: 240 mg codeine daily

Children aged 12 years to 18 years ONLY: the recommended codeine dose is 30–60 mg every 6 hours when necessary, up to a maximum codeine dose of 240 mg daily; the SPC states the dose is based on body weight (0.5–1 mg/kg), so no single per-kg figure is given. Codeine must NOT be used in children below 12 years because of the risk of opioid toxicity from variable and unpredictable metabolism of codeine to morphine, and is contraindicated in ALL paediatric patients (0–18 years) undergoing tonsillectomy and/or adenoidectomy for obstructive sleep apnoea. Not recommended in children aged 12–18 years with compromised respiratory function (including neuromuscular disorders, severe cardiac or respiratory conditions, upper respiratory or lung infections, multiple trauma or extensive surgical procedures). Verify against a children's formulary before prescribing.

Dose adjustments

Renal

Codeine should be avoided, or the dose reduced, in patients with renal or hepatic impairment (§4.4). Liver disease and severe hepatic dysfunction are contraindications. No numeric renal dose adjustment is stated in this SPC.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Acute respiratory depression; obstructive airways disease; use with caution or reduced dose in asthma and avoid during an acute asthma attack
Hypersensitivity to codeine or other opioid analgesics or to any of the excipients
Liver disease, severe hepatic dysfunction; acute alcoholism; comatose patients
Raised intracranial pressure or head injury (use should be avoided — risk of respiratory depression and raised intracranial pressure, and interference with pupillary and other responses vital for neurological assessment)
Conditions where inhibition of peristalsis is to be avoided, risk of paralytic ileus, abdominal distension, or acute diarrhoeal conditions such as acute ulcerative colitis or antibiotic-associated (e.g. pseudomembranous) colitis, or diarrhoea caused by poisoning
All paediatric patients (0–18 years) undergoing tonsillectomy and/or adenoidectomy for obstructive sleep apnoea; children under 12 years; women during breastfeeding; patients known to be CYP2D6 ultra-rapid metabolisers

Side effects

Constipation, nausea, vomiting, dry mouth and stomach cramps
Drowsiness, dizziness, headache (prolonged use of a painkiller for headaches can make them worse); confusion; convulsions especially in infants and children
Respiratory depression with large doses; dyspnoea
Postural hypotension, facial flushing, tachycardia, palpitations and bradycardia; hypotension with large doses
Drug dependence, tolerance and drug withdrawal syndrome with regular prolonged use
Urinary retention, difficulty with micturition, ureteric spasm; miosis and blurred or double vision; biliary spasm; allergic skin reactions including rash, urticaria and pruritus

Interactions

Monoamine oxidase inhibitors (MAOIs) — §4.4 begins a warning on administration of pethidine and possibly other opioid analgesics to patients taking an MAOI, but the statement was truncated at the source-fetch limit; check the SPC directly
CYP2D6 status — codeine is metabolised by CYP2D6 to morphine: patients deficient in the enzyme will not obtain adequate analgesia, while extensive or ultra-rapid metabolisers are at increased risk of opioid toxicity even at commonly prescribed doses (ultra-rapid metabolisers are contraindicated)
Alcohol — acute alcoholism is a contraindication (§4.3)
Full §4.5 interaction section was not retrieved in this bundle — check the SPC directly before relying on this list

Clinical monograph

How it works

Codeine is a prodrug metabolised by CYP2D6 to morphine, which acts on central mu-opioid receptors to reduce pain perception; it also has a direct antitussive and constipating effect.

Prescribing in practice

Analgesic response and toxicity depend on CYP2D6 metaboliser status — ultra-rapid metabolisers can develop life-threatening opioid effects, so codeine is contraindicated during breastfeeding and avoided in children and those with known ultra-rapid metabolism.
Combine with caution with other CNS depressants and CYP2D6 inhibitors, anticipate constipation and the risk of tolerance and dependence with continued use, and avoid in acute respiratory depression or paralytic ileus.
Use the lowest effective dose for the shortest time and reduce or avoid in significant renal or hepatic impairment per the SPC.

Monitoring

Monitor pain relief, sedation and respiratory status when used in higher or repeated doses, and review bowel function and ongoing need.

Counselling the patient

May cause drowsiness and constipation; avoid alcohol and do not drive if affected.
Use only as needed for short-term pain and follow the stated maximum frequency.
Seek advice before stopping after regular use, as the dose may need tapering.

Evidence & guidelines

MHRA advice restricts codeine for pain in children and during breastfeeding because of the risk of morphine toxicity in CYP2D6 ultra-rapid metabolisers.

Reference: MHRA DSU 2013 (Children Under 18); MHRA DSU 2015 (Breastfeeding); EMA Codeine Review 2013; SPC Codeine Phosphate Tablets; 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).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways