Antiplatelet Drugs – Classification, Uses

Introduction

An antiplatelet drug , also known as a platelet agglutination inhibition of platelet aggregation inhibitor, 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.

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 clots to form by interfering with the platelet activation process in primary hemostasis.

What is the most common antiplatelet drug?

Aspirin is the most common antiplatelet. At a low dose, aspirin reduces inflammation in the arteries. You may be put on aspirin to lower your risk of getting heart disease.

Other antiplatelets may be prescribed when you’ve had a heart event or your risk of having one is higher.

Classification of drugs

Irreversible cyclooxygenase inhibitors

• Aspirin
• Triflusal (Disgren)
• Adenosine diphosphate (ADP) receptor inhibitors
• angrelor (Kengreal)
• Clopidogrel (Plavix)
• Prasugrel (Effient)
• Ticagrelor (Brilinta)
• Ticlopidine (Ticlid)

Phosphodiesterase inhibitors

• Cilostazol (Pletaal)
• Protease-activated receptor-1 (PAR-1) antagonists
• Vorapaxar (Zontivity)

Glycoprotein IIB/IIIA inhibitors (intravenous use only)

• Abciximab (ReoPro)
• Eptifibatide (Integrilin)
• Tirofiban (Aggrastat)

Adenosine reuptake inhibitors

• Dipyridamole (Persantine)

Thromboxane inhibitors

• Thromboxane synthase inhibitors
• Thromboxane receptor antagonists- Terutroban

Drug toxicity

Antiplatelet drugs effect may be affected by patient’s medications, current medical conditions, food and supplements taken.

Antiplatelet drugs effect may be increased or decreased.

An increase in antiplatelet effect would increase the risk of bleeding and results in prolonged or excessive bleeding.

A decrease in antiplatelet effect would reduce the risk of bleeding and potentially increase the thromboembolic risk.

Drug toxicity also may increased when multiple antiplatelet drugs are used. Gastrointestinal bleeding is a common adverse event seen in many patients.

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 after the platelet activation at the site of vascular damage crucial to the development of arterial thrombosis.

Aspirin and Triflusal are also antiplatelets.

Aspirin as being an antiplatelet reduce the inflammation in the arteries.

Triflusal inhibits platelet aggregation and interaction of platelets with subendothelium.

Antiplatelets drugs in detail

Ticagrelor is a faster and more potent P2Y12 inhibitor that demonstrated a significant clinical benefit over clopidogrel in ACS.

It is therefore recommended as a first-line agent over clopidogrel in ACS and can be used in high-risk PCI in patients with stable angina.

Clopidogrel, sold under the trade name PLAVIX among others, is an antiplatelet medication used to reduce the risk of heart disease and stroke in those at high risk.

It is also used together with aspirin in heart attacks and following the placement of a coronary artery stent. It is taken by mouth.

Prasugrel is a drug used to prevent formation of blood clots. It is a platelet inhibitor and an irreversible antagonist of P2Y,2 ADP receptors and is of the thienopyridine drug class.

Eptifibatide, is an antiplatelet drug of the glycoprotein llb/llla inhibitor class. Eptifibatide is a cyclic heptapeptide derived from a disintegrin protein found in the venom of the southeastern pygmy rattlesnake.

It belongs to the class of the arginine-glycine-aspartate-mimetics and reversibly binds to platelets.

Ticlopidine is an antiplatelet drug in the thienopyridine family which is an adenosine diphosphate receptor inhibitor. Research initially showed that it was useful for preventing strokes and coronary stent occlusions.

Abciximab or Abciximab a glycoprotein llb/llla receptor antagonist trade name ReoPro, is a platelet aggregation inhibitor mainly used during and after coronary artery procedures like angioplasty to prevent

Cilostazol, sold under the brand name PLETAL among others, is a medication used to help the symptoms of intermittent claudication in peripheral vascular disease. If no improvement is seen after 3 months, stopping the medication is reasonable. It may also be used to prevent stroke.

It is taken by mouth.

Dipyridamole (trademarked as Persantine and others) is a nucleoside transport inhibitor and a PDE3 inhibitor medication that inhibits blood clot formation when given chronically and causes blood vessel dilation when given at high doses over a short time.

Terutroban is an antiplatelet agent developed by Servier Laboratories. It is a selective thromboxane prostanoid antagonist and is an orally active drug in clinical development for the secondary prevention of acute thrombotic complications.

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