Opioid Analgesic (Weak) Pregnancy: Caution during pregnancy, especially first trimester; possible association with respiratory and cardiac malformations after first-trimester exposure. Regular use may cause fetal drug dependence and neonatal withdrawal. Administration during labour may depress neonatal respiration. Breastfeeding: administration to nursing women not recommended (contraindicated during breastfeeding).

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: Lowest effective dose for the shortest period; usual max single/period dosing per indication (see notes)

Route: Oral

Frequency: Up to 4 times a day at intervals of not less than 6 hours (mild to moderate pain)

Max: Codeine should not exceed 240 mg daily

ELDERLY: dosage should be reduced in elderly patients (applies to all indications). Mild to moderate pain: use lowest effective dose for shortest period; duration of treatment limited to 3 days and if no effective pain relief is achieved patients/carers should seek a physician's views. Dry or painful cough: 15-30 mg 3-4 times daily. Diarrhoea: 30 mg three to four times daily (range 15-60 mg). Avoid or reduce dose in renal or hepatic impairment. Contraindicated in patients known to be CYP2D6 ultra-rapid metabolisers. Children <12 years: contraindicated. Children 12-18 years (pain): 30-60 mg every 6 hours when necessary, max 240 mg daily (0.5-1 mg/kg).

Paediatric dose

Route: Oral

Frequency: Every 6 hours when necessary (children 12-18 years, for pain)

Max: 240 mg daily

Children 12-18 years (mild to moderate pain): 30-60 mg every 6 hours when necessary, up to a maximum codeine dose of 240 mg daily; dose is based on body weight (0.5-1 mg/kg). Children <12 years: codeine should NOT be used (risk of opioid toxicity from variable/unpredictable metabolism to morphine). Contraindicated in all paediatric patients (0-18 years) undergoing tonsillectomy/adenoidectomy for obstructive sleep apnoea. For cough: contraindicated <12 years; not recommended 12-18 years with compromised respiratory function. For diarrhoea: not recommended.

Dose adjustments

Renal

Avoid or reduce dose in patients with renal impairment.

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

Acute respiratory depression
Hypersensitivity to codeine or other opioid analgesics or to any excipient
Obstructive airways disease
Liver disease / severe hepatic dysfunction
Acute alcoholism
Conditions where inhibition of peristalsis is to be avoided, risk of paralytic ileus, abdominal distension, or acute diarrhoeal conditions (e.g. acute ulcerative colitis, antibiotic-associated/pseudomembranous colitis, diarrhoea caused by poisoning)
Comatose patients
All paediatric patients (0-18 years) undergoing tonsillectomy and/or adenoidectomy for obstructive sleep apnoea syndrome
Women during breastfeeding
Patients known to be CYP2D6 ultra-rapid metabolisers

Side effects

Drowsiness
Nausea and vomiting
Constipation
Confusion
Respiratory depression (with large doses)

Interactions

MAOIs: administration of pethidine and possibly other opioid analgesics to patients taking a monoamine oxidase inhibitor has been associated with reactions (see SPC section 4.4/4.5)
CNS depressants (additive effects; risk of sedation/respiratory depression)

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).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Pathways