Which agent is a thrombolytic used to dissolve clots in myocardial infarction?

• A. Streptokinase
• B. Aspirin
• C. Clopidogrel
• D. Warfarin

Answer: (A)

Thrombolytic therapy dissolves an existing clot by turning on the body's fibrinolytic system. It does this by activating plasminogen to plasmin, which breaks down fibrin strands that hold the clot together. Streptokinase is a thrombolytic that facilitates this process, leading to clot dissolution in the setting of myocardial infarction when rapid reperfusion is needed and other options like immediate PCI aren’t available.

Aspirin and clopidogrel, while important for preventing future clots by inhibiting platelet aggregation, do not rapidly dissolve an already formed clot. Warfarin is an anticoagulant that prevents new clot formation by interfering with vitamin K–dependent clotting factors, not by breaking down an existing clot. So, among these choices, streptokinase best fits the role of a thrombolytic used to dissolve clots in myocardial infarction.