NAPLEX (North American Pharmacist Licensure Examination) Practice Exam

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Study for the NAPLEX exam with a comprehensive quiz featuring multiple-choice questions and in-depth explanations. Build your pharmacological knowledge and increase your chances of passing the pharmacist licensure examination!

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!

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Which is a CYP inhibitor?

Smoking
Grapefruit
Phenytoin
Carbamazepine

The correct answer is: Grapefruit

Grapefruit is a CYP inhibitor because it contains compounds that can inhibit the activity of specific cytochrome P450 enzymes in the liver. This inhibition can result in altered metabolism of certain drugs that are substrates for these enzymes, leading to potential drug interactions and changes in drug levels in the body. Smoking, phenytoin, and carbamazepine are not CYP inhibitors. Smoking can induce the activity of some CYP enzymes, leading to increased metabolism of certain drugs. Phenytoin and carbamazepine are known to induce the activity of CYP enzymes rather than inhibit them, impacting the metabolism of various drugs in the body.