Anti-platelet and Anti-coagulants drugs

Platelet aggregation inhibitors
Platelet aggregation inhibitors decrease the formation of a platelet-rich clot or decrease the action of chemical signals that promote platelet aggregation.
Therapeutic uses
These agents are beneficial in the:
1-Prevention and treatment of occlusive cardiovascular diseases,
2- In the maintenance of vascular grafts and arterial patency,
3- Adjuncts to thrombin inhibitors or thrombolytic therapy in MI
1- Aspirin
Mechanism of action
Aspirin inhibits thromboxane A2 synthesis by acetylation of a serine residue on the active site of COX-1, thereby irreversibly inactivating the enzyme .This shifts the balance of chemical mediators to favor the anti aggregatory effects of prostacyclin, thereby preventing platelet aggregation. Aspirin is the only antiplatelet agent that irreversibly inhibits platelet function.
Therapeutic use:
Aspirin used in the prophylactic treatment of transient cerebral ischemia, to reduce the incidence of recurrent MI, and to decrease mortality in the setting of primary and secondary prevention of MI. Complete inactivation of platelets occurs with 75 mg of aspirin given daily. The recommended dose of aspirin ranges from 50 to 325 mg daily.

2-Ticlopidine, Clopidogrel, prasugrel, and ticagrelor
Mechanism of action:
These drugs inhibit the binding of ADP to its receptors on platelets and, thereby, inhibit the activation of the GP IIb/IIIa receptors required for platelets to bind to fibrinogen and to each other.
Therapeutic use:
Clopidogrel is approved for prevention of atherosclerotic events in patients with a recent MI or stroke and in those with established peripheral arterial disease.
Adverse effects:
These agents can cause prolonged bleeding for which there is no antidote. Ticlopidine is associated with severe hematologic reactions that limit its use, such as agranulocytosis, thrombotic thrombocytopenic purpura (TTP), and aplastic anemia. Clopidogrel causes fewer adverse reactions.
3-Abciximab, eptifibatide, and tirofiban
Mechanism of action
A chimeric monoclonal antibody, abciximab ,inhibits the GP IIb/IIIa receptor complex. By binding to GP IIb/IIIa, abciximab blocks the binding of fibrinogen and von Willebrand factor and, consequently, aggregation does not occur.
Therapeutic use: These agents are given intravenously, along with heparin and aspirin, as an adjunct to PCI (percutaneous coronary intervention) for the prevention of cardiac ischemic complications.