How Do Protease Activated Receptor-1 (PAR-1) Inhibitors Work?

Protease-activated receptor-1 (PAR-1) inhibitors are a new class of antiplatelet agents used to reduce the risk of a heart attack in people with coronary artery disease who are at an increased risk for atherosclerotic occlusive thrombotic events. PAR-1 inhibitors work by inhibiting thrombin-related platelet aggregation.

A tear in the lining of the coronary artery with a disease exposes inactive platelets to collagen and other factors present in the plasma. These factors activate the platelets to become sticky and aggregate at the site of the tear. These activated platelets release molecules that trigger a cascade of coagulation factors and increase thrombin. Thrombin is responsible for the formation of a fibrin net that traps platelets and red blood cells and forms a blood clot to seal the injured area.

Thrombin is also responsible for activating circulating platelets by binding with PAR-1 receptors present on the surface of the platelets. One molecule of thrombin can activate multiple PAR-1 receptors. Thrombin also amplifies the coagulation factors, increasing thrombin, fibrin, and activated platelets, and thus, the size of the clot increases in such a way that the artery is occluded, resulting in myocardial infarction (heart attack).

• PAR-1 inhibitors are taken orally and used together with other medications, such as aspirin and clopidogrel to help prevent heart attacks and strokes in people who have had a heart attack or have poor blood flow (peripheral arterial disease).

Common side effects of PAR-1 inhibitors include:

• Bleeding
• Anemia (lack of healthy red blood cells to carry oxygen sufficient for the body)
• Vision changes
• Depression
• Rash
• Rare but serious side effects of PAR-1 inhibitors may include:
• Intracranial hemorrhage (bleeding within the skull)

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Drug name includes:

• Vorapaxar (Zontivity)