Drug interactions
Codeine + Darifenacin
Severity: Moderate
Codeine and Darifenacin: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Codeine requires CYP2D6 to be converted to morphine for much of its analgesic effect. Darifenacin is a moderate CYP2D6 inhibitor and may reduce this conversion, so analgesia may be weaker. Constipation and urinary retention may also add up.
What this interaction means in plain words
Codeine and Darifenacin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Codeine belongs to Musculoskeletal; Darifenacin belongs to Genitourinary.
Why it happens
Darifenacin inhibition of CYP2D6 reduces codeine bioactivation to morphine.
What to do
Monitor pain control and consider a non-CYP2D6-dependent opioid if analgesia is inadequate. Watch for constipation and urinary retention.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Darifenacin
Other interactions of Codeine
- Alvimopan + Codeine Contraindicated
- Codeine + Isocarboxazid Contraindicated
- Codeine + Olanzapine / samidorphan Contraindicated
- Codeine + Phenelzine Contraindicated
- Codeine + Tranylcypromine Contraindicated
- Alfentanil + Codeine Major
Frequently asked questions
Can I take Codeine with Darifenacin?
MediHelp rates the interaction as moderate. Codeine and Darifenacin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Codeine requires CYP2D6 to be converted to morphine for much of its analgesic effect. Darifenacin is a moderate CYP2D6 inhibitor and may reduce this conversion, so analgesia may be weaker. Constipation and urinary retention may also add up.
How serious is the interaction between Codeine and Darifenacin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor pain control and consider a non-CYP2D6-dependent opioid if analgesia is inadequate. Watch for constipation and urinary retention.
What other medicines interact with Darifenacin?
MediHelp also lists interactions of Darifenacin with, for example, Atazanavir, Bethanechol, Clarithromycin. The full list is on the Darifenacin page.
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