Comparative Pharmacology
Head-to-head clinical analysis: CODEINE versus WESTADONE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CODEINE versus WESTADONE.
Codeine vs WESTADONE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Codeine is an opioid agonist that binds to mu-opioid receptors in the CNS, inhibiting ascending pain pathways and altering pain perception. It is a prodrug converted to morphine via CYP2D6, which mediates most of its analgesic effects.
Mu-opioid receptor agonist; also acts as an NMDA receptor antagonist and inhibits serotonin and norepinephrine reuptake.
Oral: 30-60 mg every 4-6 hours as needed; maximum 360 mg per day. Intramuscular/Subcutaneous: 30-60 mg every 4-6 hours as needed. Use lowest effective dose for shortest duration.
Oral: 2.5-10 mg every 4-6 hours as needed for pain; maximum 40 mg per day.
None Documented
None Documented
The terminal elimination half-life of codeine is approximately 2.5 to 3.5 hours in adults with normal renal function. In patients with renal impairment, the half-life may be prolonged to up to 8 hours, necessitating dose adjustment.
Clinical Note
moderateCodeine + Torasemide
"The risk or severity of adverse effects can be increased when Codeine is combined with Torasemide."
Clinical Note
moderateDihydrocodeine + Torasemide
"The risk or severity of adverse effects can be increased when Dihydrocodeine is combined with Torasemide."
Clinical Note
moderateCodeine + Etacrynic acid
"The risk or severity of adverse effects can be increased when Codeine is combined with Etacrynic acid."
Clinical Note
moderateDihydrocodeine + Etacrynic acid
Terminal elimination half-life: 15-60 hours (mean ~24 hours). Clinical context: Prolonged half-life supports once-daily dosing in opioid maintenance; accumulation occurs with repeated dosing due to long half-life.
Codeine is eliminated primarily via renal excretion (about 90% as inactive metabolites, mainly codeine-6-glucuronide and norcodeine, with less than 10% as free codeine). Biliary/fecal excretion accounts for approximately 10% of the dose.
Primarily renal (40-50% as unchanged methadone and its metabolites, 15-20% as metadone-N-oxide), biliary/fecal (5-10%).
Category D/X
Category C
Opioid Agonist
Opioid Agonist
"The risk or severity of adverse effects can be increased when Dihydrocodeine is combined with Etacrynic acid."