A drug that is a substrate for CYP3A4 is administered concurrently with a potent CYP3A4 inhibitor. What is the most likely outcome regarding the substrate drug's concentration?

The correct answer to the question "A drug that is a substrate for CYP3A4 is administered concurrently with a potent CYP3A4 inhibitor. What is the most likely outcome regarding the substrate drug's concentration?" is Option B: Increased plasma concentration.

The other options — A) Decreased plasma concentration, C) No change in plasma concentration, D) Increased renal clearance — are incorrect for this USMLE Exam Prep question. As explained above: Inhibition of CYP3A4, a major metabolic enzyme, will decrease the metabolism of its substrate drug. This leads to reduced drug breakdown and thus an increased plasma concentration of the substrate dr…