Flecainide with Darifenacin Interaction Details
Brand Names Associated with Flecainide
- Flecainide
- Tambocor®
Brand Names Associated with Darifenacin
- Darifenacin
- Enablex®
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 25, 2023
Interaction Effect
Increased flecainide exposure with an increased risk of cardiac arrhythmias
Interaction Summary
Coadministered darifenacin may increase flecainide exposure, causing a potential risk of arrhythmias or other serious adverse effects. Flecainide, like imipramine, is metabolized primarily by the CYP2D6 isoenzyme and it has a narrow therapeutic window. The mean maximum concentration (Cmax) and area under the concentration-time curve (AUC) of imipramine increased 57% and 70%, respectively, when used together with darifenacin 30 mg once daily at steady-state. Note: The recommended dose of darifenacin is 7.5 or 15 mg once daily. The AUC of desipramine, the active metabolite of imipramine, increased 3.6-fold. Caution should be used with the coadministration of darifenacin and CYP2D6 substrates with a narrow therapeutic window, such as flecainide.
Severity
Major
Onset
Delayed
Evidence
Theoretical
How To Manage Interaction
Use caution with the coadministration of darifenacin and other CYP2D6 substrates with a narrow therapeutic window, such as flecainide. Monitor for flecainide toxicity.
Mechanism Of Interaction
Competitive inhibition of CYP2D6-mediated flecainide metabolism
Flecainide Overview
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Flecainide is used to prevent certain types of life-threatening irregular heartbeats. Flecainide is in a class of medications called antiarrhythmics. It works by slowing electrical signals in the heart to stabilize the heart rhythm.
Darifenacin Overview
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Darifenacin is used to treat an overactive bladder (a condition in which the bladder muscles contract uncontrollably and cause frequent urination, urgent need to urinate, and inability to control urination). Darifenacin is in a class of medications called antimuscarinics. It works by relaxing the bladder muscles to prevent urgent, frequent, or uncontrolled urination.
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Definitions
Severity Categories
Contraindicated
These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.
Major
This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.
Moderate
This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.
Minor
While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.
Onset
Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.
Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.
Evidence
Level of documentation of the interaction.
Established: The interaction is documented and substantiated in peer-reviewed medical literature.
Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.
How To Manage The Interaction
Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.
It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.
Mechanism Of Interaction
The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.
Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.
Where Does Our Information Come From?
Information for our drug interactions is compiled from several drug compendia, including:
The prescribing information for each drug, as published on DailyMED, is also used.
Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.
The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.