PCSK9 inhibitors are used to treat high cholesterol and familial hypercholesterolemia. They can also help reduce the risk of heart attack and stroke in people with heart disease. These medications work by blocking a protein in the body called PCSK9, which then helps your liver remove more LDL cholesterol (the "bad" cholesterol) from your blood. PCSK9 inhibitors are injectable medications. Examples include Repatha (evolocumab) and Praluent (alirocumab). You will need to get these injections regularly to keep your cholesterol levels in check.