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Weak Opioid·Analgesia - Opioids
Mild to moderate pain, severe dry cough, short-term diarrhea management
Max Dose
240 mg/day
Half-life
3 h
Constipation
SEVERE
CYP2D6 Prodrug
VARIABLE
Overview
A weak opioid prodrug. Relies entirely on the liver to convert it into morphine to provide pain relief. Highly unpredictable efficacy across the population due to genetics.
Maximum Dose
Max 240 mg/day.
Clinical Focus
Causes profound constipation. Up to 10% of Caucasians gain zero pain relief because they lack the enzyme to convert it to morphine.
Bottom Line
Codeine is a weak opioid prodrug for mild-moderate pain, but has highly variable efficacy due to CYP2D6 polymorphisms (poor to ultra-rapid metabolisers) and is contraindicated in children under 12.
Brand Names
Panadeine Forte (combo), Panadeine (combo), Actacode
Oral Routes
Tablets (30 mg). Usually combined with Paracetamol (e.g., 500mg/30mg).
Prescribing & PBS
Prescription Only (S4).
Primary
Mild to moderate pain, severe dry cough, short-term diarrhea management.
Clinical Place
Step 2 on the WHO analgesic ladder. Increasingly superseded by safer agents due to erratic metabolism.