Fluconazole with Alfuzosin Interaction Details
Brand Names Associated with Fluconazole
- Diflucan®
- Fluconazole
Brand Names Associated with Alfuzosin
- Alfuzosin
- Uroxatral®
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 27, 2023
Interaction Effect
Increased alfuzosin exposure and an increased risk of QT interval prolongation
Interaction Summary
The metabolism of alfuzosin, a CYP3A4 substrate, may be inhibited by concomitant administration of fluconazole, a moderate CYP3A4 inhibitor. Increased alfuzosin plasma concentrations can lead to QT interval prolongation and torsade de pointes. Therefore, concomitant use of fluconazole and CYP3A4 substrates that prolong the QT interval, such as alfuzosin, is contraindicated. Fluconazole-mediated CYP3A4 inhibition may continue for 4 to 5 days after discontinuation because of the long half-life .
Severity
Contraindicated
Onset
Unspecified
Evidence
Theoretical
How To Manage Interaction
Concomitant use of fluconazole with CYP3A4 substrates that prolong the QT interval, such as alfuzosin, is contraindicated due to the potential for increased alfuzosin plasma concentrations, thereby increasing the risk for QT interval prolongation and torsades de pointes. Fluconazole-mediated CYP3A4 inhibition may continue for 4 to 5 days after discontinuation because of the long half-life .
Mechanism Of Interaction
Inhibition of CYP3A4-mediated alfuzosin metabolism by fluconazole; additive effects on QT interval prolongation
Literature Reports
A) In a postmarketing study that evaluated the effect of concomitant administration of alfuzosin with another QT interval-prolonging drug of similar effect size, the observed QT interval prolongation was greater than that seen with either drug alone, but was not more than additive. The corrected (Fridericia) QT interval (QTcF) increased by 5.9 milliseconds (upper bound of 95% confidence interval (CI), 9.4 milliseconds). The QTcF increase observed with moxifloxacin 400 mg (positive control) was 10.2 milliseconds (upper bound 95% CI, 13.8 milliseconds). The mean placebo-subtracted QTcF increase following administration of alfuzosin 10 mg alone was 1.9 milliseconds (upper bound 95% CI, 5.5 milliseconds) .
Fluconazole Overview
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Fluconazole is used to treat fungal infections, including yeast infections of the vagina, mouth, throat, esophagus (tube leading from the mouth to the stomach), abdomen (area between the chest and waist), lungs, blood, and other organs. Fluconazole is also used to treat meningitis (infection of the membranes covering the brain and spine) caused by fungus. Fluconazole is also used to prevent yeast infections in patients who are likely to become infected because they are being treated with chemotherapy or radiation therapy before a bone marrow transplant (replacement of unhealthy spongy tissue inside the bones with healthy tissue). Fluconazole is in a class of antifungals called triazoles. It works by slowing the growth of fungi that cause infection.
Alfuzosin Overview
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Alfuzosin is used in men to treat symptoms of an enlarged prostate (benign prostatic hyperplasia or BPH), which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency. Alfuzosin is in a class of medications called alpha blockers. It works by relaxing the muscles in the prostate and bladder to allow urine to flow more easily.
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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.