NAPLEX (North American Pharmacist Licensure Examination) Practice Exam

Disable ads (and more) with a membership for a one time $2.99 payment

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!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.


Identify a substrate of CYP-1A2.

  1. S-warfarin

  2. Theophylline

  3. Methadone

  4. Tacrolimus

The correct answer is: Theophylline

CYP-1A2 is an enzyme in the liver that is responsible for metabolizing substances in our body. The other options, S-warfarin, methadone, and tacrolimus, are also substrates that are metabolized by other enzymes. S-warfarin, for example, is primarily metabolized by CYP-2C9, while methadone is metabolized by CYP-3A4 and CYP-2D6. Tacrolimus is metabolized by multiple enzymes, including CYP-3A4. Therefore, only theophylline is correctly identified as a substrate of CYP-1A2.