Overview
Clopidogrel is an antiplatelet medication used to reduce the risk of heart disease and stroke in those at high risk. It is often used together with aspirin in dual antiplatelet therapy after a heart attack or stent placement.

Mechanism of Action
It is a prodrug that requires activation by liver enzymes (CYP450 system). The active metabolite irreversibly binds to the P2Y12 class of ADP receptors on platelets, inhibiting platelet activation and aggregation.

Dosage and Administration
The standard maintenance dose is 75 mg once daily. For acute coronary syndrome, a loading dose of 300 mg or 600 mg is typically given initially.

Side Effects
The most significant side effect is an increased risk of bleeding, including gastrointestinal bleeding and easy bruising. Rare but serious side effects include thrombotic thrombocytopenic purpura (TTP).

Contraindications
Contraindicated in patients with active pathological bleeding, such as peptic ulcer or intracranial hemorrhage.

Pregnancy and Lactation
It should be used during pregnancy only if clearly needed. It is not known whether it is excreted in human milk; breastfeeding is generally not recommended during treatment.