Atazanavir with Vardenafil Interaction Details
Brand Names Associated with Atazanavir
- Atazanavir
- ATZ
- Reyataz®
Brand Names Associated with Vardenafil
- Levitra®
- Staxyn®
- Vardenafil
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Feb 29, 2024
Interaction Effect
Increased vardenafil exposure and an increased risk of QT interval prolongation
Interaction Summary
Although the interaction between atazanavir, a strong CYP3A4 inhibitor, and vardenafil has not been studied, concomitant use of ritonavir, another strong CYP3A4 inhibitor, at a dose of 600 mg twice daily and vardenafil at a dose of 5 mg increased the Cmax and AUC by 13-fold and 49-fold, respectively, and significantly prolonged the vardenafil half-life to 26 hours. Coadministration of atazanavir and vardenafil may have additive effects on the QT interval as both the drugs prolong the QT interval. Use caution when atazanavir and vardenafil are coadministered. If ritonavir-boosted atazanavir is given concomitantly with vardenafil, do not exceed a vardenafil dose of 2.5 mg every 72 hours[1]. If atazanavir (without ritonavir) is given concomitantly with vardenafil, do not exceed a vardenafil dose of 2.5 mg every 24 hours. Monitoring for vardenafil adverse events (e.g., hypotension, syncope, priapism, and visual changes) is also recommended [2]. Do not use orally disintegrating vardenafil with atazanavir [3].
Severity
Major
Onset
Unspecified
Evidence
Probable
How To Manage Interaction
Coadministration of atazanavir and vardenafil may have additive effects on the QT interval as both the drugs prolong the QT interval. Use caution when atazanavir (with or without ritonavir) and vardenafil are coadministered as this may result in increased vardenafil plasma concentrations. If ritonavir-boosted atazanavir is given concomitantly with vardenafil, do not exceed a vardenafil dose of 2.5 mg every 72 hours[1]. If atazanavir (without ritonavir) is given concomitantly with vardenafil, do not exceed a vardenafil dose of 2.5 mg every 24 hours. Monitor for vardenafil adverse events including hypotension, syncope, priapism, and visual changes [2]. Do not use orally disintegrating vardenafil with atazanavir [3].
Mechanism Of Interaction
Inhibition of CYP3A4-mediated vardenafil metabolism by atazanavir; additive QT interval prolongation
Literature Reports
A) Although the interaction between atazanavir, a strong CYP3A4 inhibitor, and vardenafil has not been studied, concomitant use of ritonavir, another strong CYP3A4 inhibitor, at a dose of 600 mg twice daily and vardenafil at a dose of 5 mg increased the Cmax and AUC by 13-fold and 49-fold, respectively, and significantly prolonged the vardenafil half-life to 26 hours [1].
B) In a single-dose, double-blind, randomized, placebo- and active-controlled crossover study, 59 male patients receiving vardenafil 10 mg (therapeutic), vardenafil 80 mg (supratherapeutic), or moxifloxacin 400 mg experienced similar increases in QTc interval measurements taken one hour after dosing. Single-dose administration resulted in a placebo-subtracted mean change from baseline QT (uncorrected) of 3 msec (90% confidence interval [CI]: 1, 5) for moxifloxacin 400 mg and -2 msec (90% CI: -4, 0) for both vardenafil 10 mg and 80 mg. Mean change from baseline Fridericia QT correction was 10 msec (90% CI: 8, 11) for vardenafil 80 mg, and 8 msec (90% CI: 6, 9) for both vardenafil 10 mg and moxifloxacin. Mean change from baseline for individual QT correction was 4 msec (90% CI: 3, 6) for vardenafil 10 mg, 6 msec (90% CI: 4, 7) for vardenafil 80 mg, and 7 msec (90% CI: 5, 8) for moxifloxacin. Mean increases in heart rate with vardenafil 10 mg and 80 mg were 5 and 6 beats per minute, respectively, compared with placebo [1][3].
References
1 ) Product Information: LEVITRA(R) oral tablets, vardenafil HCl oral tablets. Bayer Health Care Pharmaceuticals Inc (per FDA), Whippany, NJ, 2023.
2 ) Product Information: REYATAZ(R) oral capsules, atazanavir sulfate oral capsules. Bristol-Myers Squibb Company, Princeton, NJ, 2010.
3 ) Product Information: STAXYN(R) oral disintegrating tablets, vardenafil HCl oral disintegrating tablets. GlaxoSmithKline (per FDA), Research Triangle Park, NC, 2023.
Atazanavir Overview
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Atazanavir is used along with other medications to treat human immunodeficiency virus (HIV) infection in adults and children who are at least 3 months of age and weigh at least 22 lb (10 kg). Atazanavir is in a class of medications called protease inhibitors. It works by decreasing the amount of HIV in the blood. Although atazanavir does not cure HIV, it may decrease your chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as serious infections or cancer. Atazanavir must be given with other medications that treat HIV infection to completely treat the infection. Taking these medications along with practicing safer sex and making other lifestyle changes may decrease the risk of transmitting the HIV virus to other people.
Vardenafil Overview
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Vardenafil is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Vardenafil is in a class of medications called phosphodiesterase (PDE) inhibitors. It works by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Vardenafil does not cure erectile dysfunction or increase sexual desire. Vardenafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus (HIV).
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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.