Codeine and Quinidine interaction
Codeine and Quinidine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Codeine (Codeine sulfate) label · effective 2025-12-22
Interactions with Drugs Affecting Cytochrome P450 Isoenzymes The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with codeine are complex.
Use of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with Codeine Sulfate Tablets requires careful consideration of the effects on the parent drug, codeine, and the active metabolite, morphine. [See Warnings and Precautions ( 5.7 ), Drug Interactions ( 7 )] .
• The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with codeine are complex.
Risks of Interactions with Drugs Affecting Cytochrome P450 Isoenzymes The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with codeine are complex.
Risks of Concomitant Use or Discontinuation of Cytochrome P450 2D6 Inhibitors: The concomitant use of Codeine Sulfate Tablets with all cytochrome P450 2D6 inhibitors (e.g., amiodarone, quinidine) may result in an increase in codeine plasma concentrations and a decrease in active metabolite morphine plasma concentration which could result in an analgesic efficacy…
From the Quinidine (Quinidine Gluconate) label · effective 2024-08-27
In the case of prodrugs whose actions are actually mediated by P450 IID6 -produced metabolites (for example, codeine and hydrocodone , whose analgesic and antitussive effects appear to be mediated by morphine and hydromorphone, respectively), it may not be possible to achieve the desired clinical benefits in poor metabolizers.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.