Codeine is an opioid analgesic used to treat moderate to severe pain when the use of an opioid is indicated. The relief of pain (analgesia) is a primary goal for enhancing the quality of life of patients and for increasing the ability of patients to engage in day to day activities.
- Mechanism
- Curator reviewed · 9 references
Although the exact mechanism of action of codeine is still unknown, it is generally thought to be mediated through the agonism of opioid receptors, particularly the mu-opioid receptors. Morphine was previously postulated to contribute to the analgesic effect of codeine due to the O-demethylation of codeine to morphine by CYP2D6. Particularly, CYP2D6 poor metabolizer did not experience the analgesic effect of codeine. However, this is unlikely to be the main mechanism of action of codeine as only 5% of codeine is metabolized to morphine. Other hypotheses also postulate that codeine-6-glucuronide, the main metabolite of codeine, mediates the analgesic effect of codeine as it not only has an affinity to the mu receptors as codeine but also can be metabolized to morphine-6-glucuronide, which was observed to be more potent than morphine.
Binding to the mu receptors by codeine activates the G-proteins Gαi, causing a decrease in intracellular cAMP and Ca2+ level. This causes hyperpolarization of nociceptive neurons, thus imparing the transmission of pain signals.
- Primary indication
- Codeine sulfate is a form of this drug that is commonly used.Curator reviewed · 17 structured indications
- Formula / weight
- C18H21NO3 · 299.3642 g/mol (avg)
- First approval
- Canada, 1996 · United States, 1960
- Also known as
- Codeine polistirex · Codeinum · Methylmorphine
- Code names
- IDS-NC-005(SECT.-2)
- Brand names
Resolves to
OROGSEYTTFOCAN-DNJOTXNNSA-NSMILES[H][C@]12C=C[C@H](O)[C@@H]3OC4=C5C(C[C@H]1N(C)CC[C@@]235)=CC=C4OCWhat you can answer from here — as of September 27, 2026
Which drugs share a target with Codeine, and which of those have an active Phase 3 trial?
Create a free account or log in to explore the full data card.
Create Account