<prompt> Which of the following is a P-glycoprotein inhibitorRifampicinPhenytoinGriseofulvinKetoconazole  <response>: Drugs like Cyclosporine, Tacrolimus, Quinidine, Diltiazem, Verapamil, Itraconazole, Ketoconazole, Amiodarone inhibit P-glycoprotein and cause drug toxicity. 