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Opioid Analgesic (Weak) Pregnancy: Caution during pregnancy, especially the first trimester; a possible association with respiratory and cardiac malformations has been reported after first-trimester exposure. Regular use during pregnancy may cause fetal dependence and neonatal withdrawal; administration during labour may depress neonatal respiration (an antidote for the child should be readily available). Contraindicated in women during breastfeeding - administration to nursing women is not recommended (risk of infant respiratory depression).

Codeine Phosphate

Brand names: Codeine Linctus, Codipar (combination)

Codeine phosphate is a weak opioid analgesic (also used as an antitussive and antidiarrhoeal) for mild-to-moderate pain; this page concerns its use in older patients, who are more sensitive to opioid effects.

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: Mild to moderate pain: ELDERLY - dosage should be reduced in elderly patients. The SPC states no fixed adult milligram dose for pain: codeine should be used at the lowest effective dose for the shortest period of time, and the dose may be taken up to 4 times a day at intervals of not less than 6 hours
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
SOURCE: UK SPC (eMC) for Codeine phosphate 15 mg Tablets, §4.2 (https://www.medicines.org.uk/emc/product/11268/smpc). ELDERLY (this page): §4.2 states for every indication only that 'Dosage should be reduced in elderly patients' - no specific reduced milligram dose or percentage is given, so the reduction must be individualised. §4.4 adds that codeine should only be used with caution or in reduced dose in elderly or debilitated patients, or in patients with hypotension, hypothyroidism, prostatic hypertrophy, adrenocortical insufficiency, inflammatory or obstructive bowel disorders, urethral stricture, shock, convulsive disorders or myasthenia gravis, and that it should be avoided or the dose reduced in renal or hepatic impairment. DURATION (pain): treatment should be limited to 3 days; if no effective pain relief is achieved, patients/carers should be advised to seek the views of a physician. OTHER INDICATIONS - dry or painful cough: adults 15-30 mg 3-4 times daily (elderly: reduce). Diarrhoea: adults 30 mg three to four times daily (range 15-60 mg) (elderly: reduce; paediatric use not recommended). BEFORE STARTING: a discussion should be held with the patient to put in place a strategy for ending treatment, to minimise the risk of addiction and drug withdrawal syndrome. CYP2D6: ultra-rapid metabolisers are at increased risk of opioid toxicity (contraindicated); poor metabolisers may get inadequate analgesia. §4.5 was not present in the fetched bundle, so the interaction list below is drawn from §4.4 only and is incomplete.

Paediatric dose

Route: Oral
Frequency: Every 6 hours when necessary
Max: Maximum dose of codeine 240 mg daily
SPC §4.2, mild to moderate pain, children aged 12 years to 18 years only: 30-60 mg every 6 hours when necessary, up to a maximum of 240 mg codeine daily; the SPC states 'The dose is based on the body weight (0.5-1mg/kg)' - a range, so no single per-kg figure is given (dosePerKg left null deliberately). Children under 12 years: codeine should NOT be used (risk of opioid toxicity from variable, unpredictable metabolism to morphine) and it is contraindicated under 12 years for cough. Contraindicated in ALL patients aged 0-18 years undergoing tonsillectomy and/or adenoidectomy for obstructive sleep apnoea syndrome. Not recommended in children 12-18 years with compromised respiratory function. Diarrhoea: paediatric use not recommended. Verify any paediatric use against a children's formulary.

Dose adjustments

Renal

SPC §4.4: codeine should be avoided, or the dose reduced, in patients with renal (or hepatic) impairment - no specific adjusted dose is stated.

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 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)
  • Conditions where inhibition of peristalsis is to be avoided - risk of paralytic ileus, abdominal distension, or acute diarrhoeal conditions such as acute ulcerative colitis, 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 syndrome
  • Women who are breastfeeding
  • Patients known to be CYP2D6 ultra-rapid metabolisers

Side effects

  • Drowsiness, dizziness and headache (prolonged use of a painkiller for headaches can make them worse)
  • Nausea, vomiting, constipation, dry mouth and stomach cramps
  • Confusion, mood changes, euphoria/dysphoria, hallucinations; drug dependence and tolerance with regular prolonged use
  • Respiratory depression and hypotension with large doses; postural hypotension, facial flushing
  • Urinary retention/difficulty with micturition; miosis and blurred or double vision

Interactions

  • Monoamine oxidase inhibitors (MAOIs) - §4.4 warns about administration of pethidine and possibly other opioid analgesics to patients taking an MAOI (the SPC text is truncated at the source-fetch limit; §4.5 was not retrieved, so this list is incomplete)

Clinical monograph

How it works

Codeine is a prodrug metabolised by CYP2D6 to morphine, which acts on central mu-opioid receptors to produce analgesia; this metabolic step underlies much of its variability and risk.

Prescribing in practice

  • Older patients are at heightened risk of sedation, confusion, respiratory depression, constipation and falls, so use the lowest effective dose for the shortest time and review regularly.
  • CYP2D6 ultra-rapid metabolisers generate excessive morphine with risk of toxicity, while poor metabolisers gain little analgesia; it is contraindicated in children under twelve and in breastfeeding.
  • Co-prescribe a laxative for opioid-induced constipation and avoid combining with other CNS depressants where possible, with caution in renal impairment.

Monitoring

Monitor pain control, bowel function, sedation and respiratory status, and reassess the continuing need for opioid analgesia.

Counselling the patient

  • It can cause drowsiness and constipation; take any prescribed laxative and avoid alcohol.
  • Do not exceed the prescribed amount and do not drive if you feel drowsy.
  • Report excessive sleepiness, confusion or slow or difficult breathing.

Evidence & guidelines

MHRA advice highlights CYP2D6-related variability and restrictions on codeine use, and prescribing follows established analgesic and opioid-safety guidance.

Reference: MHRA Drug Safety Update 2013 (codeine in children); AGS Beers Criteria 2023; STOPP/START v3; 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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