Apr 27, 2021 · Metabolism. Codeine is primarily metabolised by two different pathways (see Figure) [2] . In most people, around 80% of codeine is conjugated to form codeine-6-glucuronide, which may have weak analgesic activity [2,7] . However, typically less than 10% of codeine undergoes CYP2D6-mediated O-demethylation to the potent analgesic, morphine [5] .

Codeine is metabolized by 10% into morphine; other metabolites are codeine-6-glucuronide and norcodeine . Codeine is a much weaker agonist at μ-opioid receptors than morphine (Table 1; K i values for 3 H-DAMGO replacement from μ-receptors of 0.35 μM for codeine compared to 0.0018 μM for morphine 4).

The CYP2D6 enzyme is entirely responsible for the metabolism of hydrocodone, 14 codeine, 13 and dihydrocodeine to their active metabolites (hydromorphone, morphine, and dihydromorphine, respectively), which in turn undergo phase 2 glucuronidation.

Between 0-15% of codeine is O-demethylated to morphine, the most active metabolite, which has a 200 fold greater affinity for the mu-opioid receptor compared to codeine. This metabolic reaction is performed by CYP2D6.

May 18, 2015 · Codeine is a prodrug metabolized by cytochrome P450 2D6 to morphine which mediates most of the analgesic effects of codeine in the body. Over 100 variants of this enzyme (CYP2D6) result in a continuum of activity.

Jul 4, 2006 · Codeine is an analgesic drug acting on μ -opiate receptors predominantly via its metabolite morphine, which is formed almost exclusively by the genetically polymorphic enzyme cytochrome P450...

It is high time to avoid codeine and possibly other stronger opioids metabolized via CYP2D6 pathway, especially in children with significant co-morbidities such as OSA or significant respiratory disease.

Codeine is an analgesic drug acting on mu-opiate receptors predominantly via its metabolite morphine, which is formed almost exclusively by the genetically polymorphic enzyme cytochrome P450 2D6 (CYP2D6).

Codeine (30 mg phosphate) was metabolized by eight human volunteers to the following six metabolites: codeine-6-glucuronide 81.0 +/- 9.3 per cent, norcodeine 2.16 +/- 1.44 per cent, morphine 0.56 +/- 0.39 per cent, morphine-3-glucuronide 2.10 +/- 1.24 per cent, morphine-6-glucuronide 0.80 +/- 0.63 p …

Mar 1, 2022 · The interpretation of codeine and other drugs in drug testing can be complicated due to the many variables that can affect the presence of metabolites. Codeine can be metabolized to norcodeine, morphine, hydrocodone, norhydrocodone, hydromorphone, and …