Directions Pharmacokinetic actions are mediated through the hepatic and gut drug-metabolizing system known as the cytochrome P540 (CYP) enzyme system. Select medications that you would likely prescribe or encounter frequently in your practice (ideally psychopharmaceutical agents). Please answer the following questions, assigned by the first letter of your last name. Include at least two references other than Stahl in your answers. Also, please write two test questions covering the information in your initial post. I–O: Please state what the CYP 2D6 enzyme is, why it is important, and what it does in the body. List common medications, foods, herbs, and/or substances that inhibit this enzyme, including any substrates, and any important medication restrictions regarding this enzyme.