What is Platelet Inhibition?

Platelet inhibition is an action of some medications. There are different kinds of platelet inhibition for different medical needs. Basically, platelet inhibitors restrict some function of the platelets, the clotting agents in the blood. They are used primarily to prevent thrombosis, or the formation of blood clots, thereby preventing heart attack and stroke. Unlike anticoagulants, which also prevent blood clotting, platelet inhibitors are effective within the arteries.

Platelets are one of the three major components of blood, along with red blood cells and white blood cells. Platelets are responsible for hemostasis, or the cessation of bleeding. Hemostasis has three stages: vasoconstriction, in which the blood vessel becomes narrower to reduce bloodflow; blockage of a break in the blood vessel wall by a platelet plug; and thrombosis, or the formation of a blood clot that will keep the wound closed until it heals.

Hemostasis and platelets are therefore extremely important in wound repair and healing. Without them, even minor injuries would be a serious medical matter. However, in some medical conditions, including cardiovascular disease, platelets are either too numerous or too aggressive, and can lead to blood clots forming unnecessarily within the blood vessels. These can impede blood flow and can be extremely serious if they reach the heart or brain, where they can cause a heart attack or stroke respectively.

Platelet inhibition is used to prevent two conditions: thrombotic cerebrovascular and thrombotic cardiovascular disease. At risk patients include those with high blood pressure, atherosclerosis or clogged arteries, or a history of heart attack or stroke. The major medical risk associated with taking platelet inhibitors is hemorrhage or excessive bleeding, but the incidence of this complication is relatively low. In patients taking low-dose aspirin as a platelet inhibitor, for example, only one in 800 will suffer from major bleeding each year.

Sometimes, platelet inhibitors are taken regularly to promote cardiovascular health, while in other instances, they are used briefly in high doses to aid in surgery or to dilate the blood vessels to treat pain. Low-dose aspirin, which can be obtained over the counter, is usually the front line treatment for maintaining cardiovascular health. Prescription drugs for platelet inhibition include Plavix, Ticlid, Pletal, and Persantine. Other platelet inhibitors, known as glycoprotein IIb/IIIa inhibitors, are administered intravenously during angioplasty, a surgery in which a restricted blood vessel is widened from within using a small balloon. These drugs use platelet inhibition to prevent a clotting reaction to the surgery, which could cause further complications.