Codeine

Category: alkaloid

Aliases: Methylmorphine

Pharmacological Mechanism

Methylated morphine prodrug — analgesic effect requires hepatic CYP2D6 demethylation to morphine, the active µ-opioid receptor agonist (~10% of dose). CYP2D6 ultrarapid metabolizers risk respiratory depression; poor metabolizers get little analgesia.

Half-Life (t½)

PO: 3h

Dosing Guidelines

• PO: Typical 30 mg (Range: 15–60 mg)

Target Organ Systems

• nervous
• respiratory
• digestive

Pathways It Modulates

• Cough reflex arc + central antitussives (inhibitor) — central cough center via μ-opioid agonism → ↓cough
• Opioid receptor signaling (activator) — μ-opioid receptor (prodrug → morphine via CYP2D6)

Chemical Identifiers

• PubChem CID: 5284371
• Formula: C18H21NO3
• Molecular weight: 299.36 g/mol
• InChIKey: OROGSEYTTFOCAN-DNJOTXNNSA-N
• SMILES: CN1CC[C@]23[C@@H]4[C@H]1CC5=C2C(=C(C=C5)OC)O[C@H]3[C@H](C=C4)O

References

• PMID 8227477