NAPLEX (North American Pharmacist Licensure Examination) Practice Exam

Which is a P-gp inducer?

1. Carbamazepine

2. Verapamil

3. Clarithromycin

4. Ritonavir

The correct answer is: Carbamazepine

Carbamazepine is a P-glycoprotein (P-gp) inducer. P-gp is an efflux transporter that helps remove drugs and toxins from cells. Inducing P-gp can lead to increased drug efflux and decreased drug concentrations inside the cell. In this case, carbamazepine induces P-gp activity, which can affect the pharmacokinetics and effectiveness of co-administered drugs that are substrates for P-gp. Verapamil, Clarithromycin, and Ritonavir are not P-gp inducers; in fact, verapamil and ritonavir are known to inhibit P-gp activity, while clarithromycin has no significant effect on P-gp.