Pharmacology Drug Classifications Practice Test

PCSK9 inhibitors are monoclonal antibodies that block the action of PCSK9, a protein that promotes the degradation of LDL receptors on liver cells. When PCSK9 is inhibited, more LDL receptors are available to pull LDL cholesterol out of the blood, lowering overall LDL-C levels. Evolocumab fits this class perfectly because it is a monoclonal antibody designed to inhibit PCSK9, increasing LDL receptor recycling and activity. This mechanism is different from other lipid-lowering approaches (for example, statins like atorvastatin reduce cholesterol by inhibiting HMG-CoA reductase), and it’s distinct from drugs used for other indications (ranitidine is an H2 blocker for gastric acid, cyclophosphamide is a chemotherapy agent). PCSK9 inhibitors are typically given by injection every few weeks and are used in familial hypercholesterolemia or statin-intolerant patients.