Belzutifan with Estradiol Interaction Details
Brand Names Associated with Belzutifan
- Belzutifan
- Welireg®
Brand Names Associated with Estradiol
- Amnestrogen® (esterified estrogens)
- Cenestin® (conjugated synthetic A estrogens)
- conjugated estrogens
- Covaryx® (as a combination product containing Esterified Estrogens, Methyltestosterone)
- Enjuvia® (conjugated synthetic B estrogens)
- Essian® (as a combination product containing Esterified Estrogens, Methyltestosterone)
- esterified estrogens
- Estrace® Tablets (estradiol)
- estradiol
- Estratab® (esterified estrogens)
- Estratest® (as a combination product containing Esterified Estrogens, Methyltestosterone)
- Estrogen
- estropipate
- Evex® (esterified estrogens)
- Femogen® (esterified estrogens)
- Femtest® (as a combination product containing Esterified Estrogens, Methyltestosterone)
- Menest® (esterified estrogens)
- Menogen® (as a combination product containing Esterified Estrogens, Methyltestosterone)
- Menrium® (as a combination product containing Chlordiazepoxide, Esterified Estrogens)
- Milprem® (as a combination product containing Conjugated Estrogens, Meprobamate)
- Ogen® Tablets (estropipate)
- Ortho-est® (estropipate)
- PMB® (as a combination product containing Conjugated Estrogens, Meprobamate)
- Premarin® Tablets (conjugated estrogens)
- Premarin® with Methyltestosterone (as a combination product containing Conjugated Estrogens, Methyltestosterone)
- Syntest® (as a combination product containing Esterified Estrogens, Methyltestosterone)

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Mar 04, 2024
Interaction Effect
Decreased plasma levels of hormonal contraceptives
Interaction Summary
Concomitant use of belzutifan and a hormonal contraceptive may decrease plasma concentrations of the contraceptive leading to contraceptive failure or an increase in breakthrough bleeding. Advise females of reproductive potential to use effective non-hormonal contraception during treatment with belzutifan and for 1 week after the last dose[1].
Severity
Major
Onset
Unspecified
Evidence
Theoretical
How To Manage Interaction
Concomitant use of belzutifan and a hormonal contraceptive may decrease plasma concentrations of the contraceptive leading to contraceptive failure or an increase in breakthrough bleeding. Advise females of reproductive potential to use effective non-hormonal contraception during treatment with belzutifan and for 1 week after the last dose[1].
Mechanism Of Interaction
Induction of CYP450-mediated hormonal contraceptive metabolism by belzutifan
References
1 ) Product Information: WELIREG(TM) oral tablets, belzutifan oral tablets. Merck Sharp & Dohme Corp (per FDA), Whitehouse Station, NJ, 2021.
Belzutifan Overview
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Belzutifan is used in adults with von Hippel-Lindau disease (VHL; a rare disease that causes tumors and cysts) to treat renal cell carcinoma (RCC; kidney cancer), central nervous system (CNS) hemangioblastomas (tumors in the brain and spinal cord), and a certain type of pancreatic cancer that does not require surgery right away. Belzutifan is in a class of medications called hypoxia-inducible factor inhibitors. It works by blocking the activity of a certain protein in people with VHL.
Estradiol Overview
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Estrogen is used to treat hot flushes ('hot flashes'; sudden strong feelings of heat and sweating) in women who are experiencing menopause ('change of life', the end of monthly menstrual periods). Some brands of estrogen are also used to treat vaginal dryness, itching, or burning, or to prevent osteoporosis (a condition in which the bones become thin and weak and break easily) in women who are experiencing or have experienced menopause. However, women who need a medication only to treat vaginal dryness or only to prevent osteoporosis should consider a different treatment. Some brands of estrogen are also to relieve symptoms of low estrogen in young women who do not produce enough estrogen naturally. Some brands of estrogen are also used to relieve the symptoms of certain types of breast and prostate (a male reproductive gland) cancer. Estrogen is in a class of medications called hormones. It works by replacing estrogen that is normally produced by the body.
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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.