codeine phosphate: clinical use

Prescribing considerations

• Confirm the indication and whether a non-opioid option is sufficient.
• Agree treatment goals and a stopping strategy; review continued need and signs of tolerance, dependence, misuse or opioid-induced hyperalgesia.
• Avoid in known CYP2D6 ultra-rapid metabolisers; consider impaired conversion if expected benefit is absent.
• Use particular caution with reduced respiratory reserve, asthma, frailty, hypotension, renal impairment, endocrine disorders, urinary obstruction, bowel disease, seizure disorders, myasthenia gravis, substance-use history or concurrent sedatives.
• Codeine linctus is prescription-only because of dependence, addiction and overdose concerns.

Contraindications and cautions

• Hypersensitivity to codeine, another opioid analgesic or product excipients.
• Acute respiratory depression; obstructive airways disease and other product-specified severe respiratory conditions.
• Product-specified liver disease or severe hepatic dysfunction.
• Acute alcoholism, coma, raised intracranial pressure or head injury where neurological assessment may be impaired.
• Paralytic ileus risk or conditions where inhibition of peristalsis must be avoided; selected acute diarrhoeal conditions.
• Known CYP2D6 ultra-rapid metabolism.
• Breastfeeding.
• Use after tonsillectomy or adenoidectomy for obstructive sleep apnoea in anyone younger than 18 years.
• Codeine for cough in children younger than 12 years.

Monitoring

• Clinical benefit and continued need.
• Sedation, respiratory status and blood pressure, particularly after initiation or with other depressants.
• Constipation, nausea, urinary retention and biliary or pancreatic symptoms.
• Early supply requests, loss of control, tolerance, dependence, withdrawal symptoms and hyperalgesia.
• Neonatal respiratory depression or withdrawal after exposure during pregnancy or labour.

Clinical pharmacology

Codeine is a centrally acting opioid with low affinity for mu-opioid receptors. CYP2D6 conversion to morphine contributes substantially to analgesia, while central suppression of the cough reflex produces its antitussive effect. Metabolites are mainly eliminated in urine.

Formulation and product differences

• The selected tablet is a white oral tablet containing lactose; relevant hereditary sugar-intolerance warnings apply.
• The selected linctus is a clear orange syrup containing sorbitol and Sunset Yellow. Sorbitol is relevant in hereditary fructose intolerance, and Sunset Yellow may cause allergic reactions.
• The linctus is licensed specifically for non-productive cough. The selected tablet additionally covers acute moderate pain, dry or painful cough and adult diarrhoea.

Tablet

Route: Oral

Strengths: 15 mg, 30 mg, 60 mg