FPGEE for National Association of Boards of Pharmacy (NABP) Practice Exam

What defines the role of cytochrome P450 in drug metabolism?

1. Inhibition of drug absorption

2. Catalyzing a diverse group of oxidative biotransformations

3. Reducing drug polarity

4. Amplifying drug activity

The correct answer is: Catalyzing a diverse group of oxidative biotransformations

The defining role of cytochrome P450 enzymes in drug metabolism involves catalyzing a diverse group of oxidative biotransformations. These enzymes are crucial for the metabolism of a vast array of substances, including drugs, toxins, and endogenous compounds. They achieve this by facilitating oxidation reactions, which typically involve the introduction of an oxygen atom into a drug molecule. This process not only transforms the chemical structure of drugs but also plays a significant role in facilitating their elimination from the body. Through these oxidative reactions, cytochrome P450 enzymes increase the solubility of drugs, enhancing their clearance and excretion, ultimately impacting their pharmacokinetics. The diversity of cytochrome P450 isoenzymes is significant; different isoforms are responsible for metabolizing various classes of drugs, making them essential in how individuals process medications. This metabolic capability highlights the importance of P450 enzymes in pharmacotherapy, particularly regarding drug interactions and individual variability in drug metabolism. Other options touch on aspects related to drug metabolism but do not accurately define the primary role of cytochrome P450. For example, inhibition of drug absorption is not a function of these enzymes; rather, it pertains to other mechanisms. Reducing drug polarity is a byproduct of some metabolic reactions but