Estradiol with Telaprevir Interaction Details

Brand Names Associated with Estradiol

Brand Names Associated with Telaprevir

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Nov 13, 2023

Interaction Effect

Decreased contraceptive effectiveness

Interaction Summary

Administration of telaprevir with ethinyl estradiol may significantly decrease plasma concentrations of ethinyl estradiol. Norethindrone concentrations were minimally effected. In a drug interaction study, concurrent administration of ethinyl estradiol and telaprevir led to significant decreases in ethinyl estradiol Cmax, AUC, and Cmin. During concurrent use of telaprevir and combination contraceptives, 2 effective non-hormonal forms of birth control should be used throughout telaprevir therapy and until approximately 2 weeks following the discontinuation of telaprevir, at which time hormonal contraceptives may be used as 1 of the 2 contraceptive measures required during ribavirin and peginterferon alfa therapy; however, specific contraceptive prescribing guidelines should be followed. Patients who are using estrogens as hormone replacement therapy should be monitored for signs of estrogen deficiency .

Severity

Major

Onset

Unspecified

Evidence

Established

How To Manage Interaction

Administration of telaprevir with ethinyl estradiol may significantly decrease plasma concentrations of ethinyl estradiol. During concurrent use of telaprevir and combination contraceptives, 2 effective non-hormonal forms of birth control should be used throughout telaprevir therapy and until approximately 2 weeks following the discontinuation of telaprevir, at which time hormonal contraceptives may be used as 1 of the 2 contraceptive measures required during ribavirin and peginterferon alfa therapy; however, specific contraceptive prescribing guidelines should be followed. Patients who are using estrogens as hormone replacement therapy should be monitored for signs of estrogen deficiency.

Mechanism Of Interaction

Unknown

Literature Reports

A) In a pharmacokinetic study (n=24), the concomitant administration of telaprevir 750 mg every 8 hours with an oral contraceptive containing ethinyl estradiol 0.035 mg and norethindrone 0.5 mg daily resulted in a 26% to 33% reduction in ethinyl estradiol exposure. Female volunteers 18 and 45 years old who were taking ethinyl estradiol 0.035 mg/norethindrone 0.5 mg for at least 3 months were enrolled. During the study, study participants received this combination contraceptive regimen for 21 days followed by a 7-day washout period, then ethinyl estradiol 0.035 mg/norethindrone 0.05 mg plus telaprevir for 21 days followed by telaprevir alone for 7 days. The mean Cmax, AUC at steady state, and Cmin for ethinyl estradiol decreased by 26%, 28% and 33%, respectively, after the administration of telaprevir. The least-squares mean ratios for ethinyl estradiol were all outside the no-effect boundaries of 0.8 to 1.25 (0.74 (90% confidence interval (CI); 0.68 to 0.80), 0.67 (90% CI; 0.63 to 0.71), and 0.72 (90% CI 0.69 to 0.75) for Cmax, Cmin, and AUC at steady state, respectively). Norethindrone and telaprevir exposures were found not to be significantly affected by the coadministration of both agents .

B) In 2 drug interaction studies (n=23 and n=24), administration of telaprevir 750 mg every 8 hours for 21 days concurrently with ethinyl estradiol 0.035 mg and norethindrone 0.5 mg daily for 21 days did not significantly change norethindrone concentrations. The norethindrone ratio estimate (norethindrone with telaprevir to norethindrone without) was 1 (90% confidence interval (CI), 0.93 to 1.07) for Cmax, 0.99 (90% CI, 0.93 to 1.05) for AUC and 1 (90% CI, 0.93 to 1.08) for Cmin for one study (n=23). In the second study (n=24), the ratio estimates were 0.85 (90% CI, 0.81 to 0.89), 0.89 (90% CI, 0.86 to 0.93), and 0.94 (0.87 to 1), respectively .

Estradiol Overview

• 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.

Telaprevir Overview

• Telaprevir is used along with two other medications (ribavirin [Copegus, Rebetol] and peginterferon alfa [Pegasys]) to treat chronic hepatitis C (an ongoing viral infection that damages the liver) in people who have not yet been treated for this condition or whose condition could not successfully be treated with ribavirin and peginterferon alfa alone. Telaprevir is in a class of medications called protease inhibitors. It works by decreasing the amount of hepatitis C virus (HCV) in the body. Telaprevir may not prevent the spread of hepatitis C to other people.

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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:

• Gold Standard Drug Database
• Micromedex
• Lexicomp
• DrugBank

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.