An antiplatelet drug (antiaggregant) is a member of a class of pharmaceuticals that decrease platelet aggregation and inhibit thrombus formation. They are effective in the arterial circulation, where anticoagulants have little effect.
Contents
- Choice of antiplatelet drug
- Dual antiplatelet therapy
- Classification
- Prevention and treatment of arterial thrombosis
- Drug toxicity
- References
They are widely used in primary and secondary prevention of thrombotic cerebrovascular or cardiovascular disease.
Antiplatelet therapy with one or more of these drugs decreases the ability of blood clot to form by interfering with platelet activation process in primary hemostasis. Antiplatelet drugs can reversibly or irreversibly inhibit the process involved in platelet activation resulting in decreased tendency of platelets to adhere to one another and to damaged blood vessels endothelium.
Choice of antiplatelet drug
A 2006 review states: "...low-dose aspirin increases the risk of major bleeding 2-fold compared with placebo. However, the annual incidence of major bleeding due to low-dose aspirin is modest—only 1.3 patients per thousand higher than what is observed with placebo treatment. Treatment of approximately 800 patients with low-dose aspirin annually for cardiovascular prophylaxis will result in only 1 additional major bleeding episode."
Dual antiplatelet therapy
Often a combination of aspirin plus an ADP/P2Y inhibitor (such as clopidogrel, prasugrel, ticagrelor, or another) is used in order to obtain greater effectiveness than with either agent alone.
Classification
The class of antiplatelet drugs include:
Prevention and treatment of arterial thrombosis
Prevention and treatment of arterial thrombosis is essential in patients with certain medical conditions whereby the risk of thrombosis or thromboembolism may result in disastrous consequences such as heart attack, pulmonary embolism or stroke. Patients who require the use of antiplatelet drugs are: stroke with or without atrial fibrillation, any heart surgery (especially prosthetic replacement heart valve), Coronary Heart Disease such as stable angina, unstable angina and heart attack, patients with coronary stent, Peripheral Vascular Disease/Peripheral Arterial Disease and apical/ventricular/mural thrombus.
Treatment of established arterial thrombosis includes the use of antiplatelet drugs and thrombolytic therapy. Antiplatelet drugs alter the platelet activation at the site of vascular damage crucial to the development of arterial thrombosis.
Thrombolytic therapy is used in myocardial infarction, cerebral infarction, and, on occasion, in massive pulmonary embolism. The main risk is bleeding. Treatment should not be given to patients having had recent bleeding, uncontrolled hypertension or a hemorrhagic stroke, or surgery or other invasive procedures within the previous 10 days.
Drug toxicity
Drug toxicity may be increased when multiple antiplatelet drugs are used. Gastrointestinal bleeding is a common adverse event seen in many patients.