NAPLEX (North American Pharmacist Licensure Examination) Practice Exam

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Prepare for the NAPLEX (North American Pharmacist Licensure Examination) Test. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

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Regarding drug interactions, what specific effect does rifampin have on hormonal contraceptives?

  1. Decreases their efficacy

  2. Increases their efficacy

  3. Changes their metabolism

  4. No effect

The correct answer is: Decreases their efficacy

Rifampin is known to induce liver enzymes, particularly cytochrome P450 enzymes, which can lead to the increased metabolism of hormonal contraceptives. This increased metabolism can result in decreased blood levels of the hormonal contraceptives, ultimately reducing their efficacy. It is essential to advise patients using hormonal contraceptives and rifampin concurrently to consider additional or alternative contraceptive methods to ensure effectiveness.