Does Aprepitant (Substance P/neurokinin 1 (NK1) receptor antagonist) reduce the effectiveness of hormonal contraception?

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Last updated: March 8, 2025View editorial policy

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From the Guidelines

Aprepitant can reduce the effectiveness of hormonal contraceptives, requiring women to use additional contraception methods during and for 28 days after treatment. This is because aprepitant is a moderate CYP3A4 enzyme inducer that accelerates the metabolism of hormonal contraceptives, potentially lowering their blood levels 1. The exact mechanism involves the induction of CYP3A4, which is responsible for the metabolism of many drugs, including hormonal contraceptives. As a result, women taking aprepitant should use barrier methods such as condoms or diaphragms alongside their regular hormonal contraception to prevent unintended pregnancies.

Key points to consider:

  • Aprepitant decreases the AUC for patients taking oral contraceptives, as stated in the package insert 1
  • The interaction applies to all hormonal contraceptives, including pills, patches, rings, implants, and hormone-containing IUDs
  • The 28-day additional protection period after completing aprepitant therapy is necessary because the enzyme induction effects persist after the medication is discontinued
  • Healthcare providers should counsel patients about this interaction before starting aprepitant therapy to prevent unintended pregnancies

It is essential to note that the interaction between aprepitant and hormonal contraceptives is significant, and women should take extra precautions to prevent unintended pregnancies. The use of barrier methods, such as condoms or diaphragms, is recommended in addition to regular hormonal contraception during and for 28 days after aprepitant treatment 1.

From the FDA Drug Label

5.3 Risk of Reduced Efficacy of Hormonal Contraceptives Upon coadministration with aprepitant, the efficacy of hormonal contraceptives may be reduced during administration of and for 28 days following the last dose of aprepitant [see Clinical Pharmacology (12.3)]. Advise patients to use effective alternative or back-up methods of contraception during treatment with aprepitant and for 1 month following the last dose of aprepitant [see Drug Interactions (7.1), Use in Specific Populations (8.3)].

Aprepitant may reduce the effectiveness of hormonal contraception. Patients should be advised to use effective alternative or back-up methods of contraception during treatment with aprepitant and for 1 month following the last dose of aprepitant 2.

From the Research

Effect of Aprepitant on Hormonal Contraception

  • There are no research papers provided to assist in answering this question regarding the effect of Aprepitant on hormonal contraception 3, 4, 5, 6, 7.
  • The studies available focus on the use of Aprepitant for the prevention of chemotherapy-induced nausea and vomiting, and its cost-effectiveness in this context.
  • None of the studies provided investigate the interaction between Aprepitant and hormonal contraception, or its potential impact on the effectiveness of hormonal contraception.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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