Drugs in different types of ischemic (coronary) heart diseases

Can you please clarify which drugs are to be used in different types of ischemic heart diseases? I am especially confused about the use of heparin/ streptokinase.

Let me start with the different drugs that affect clotting which are used in coronary artery disease:

• Antiplatelet agents - Aspirin, Ticlopidine, Clopidogrel etc.
• Anticoagulants - Warfarin, Coumarin derivatives, Heparin etc.
• Thrombolytic agents - Streptokinase, Urokinase, Alteplase, etc.

Please do not get confused with these names and their actions. Antiplatelet drugs just inhibit platelet aggregation, anticoagulants affect the coagulation pathway in various ways to prevent the formation and progression of a thrombus. Thrombolytics, as their name suggests, break down an already formed thrombus.

Now, if you study this with the pathophysiology of different types of ischemic heart disease, their uses will be quite logical.

• Stable Angina: No thrombus is present or impending - Treat to prevent platelet aggregation generally - Use antiplatelet agents. No use for heparin or thrombolytics
• Unstable angina: Fresh thrombus/ impending thrombus threatening complete blockade of coronary vessel - Treat to prevent further progression of thrombus - Use anticoagulants, especially heparin. Generally low-molecular-weight heparins are used, for example dalteparin, enoxaparin...
• Myocardial infarction: Thrombus that has completely blocked the coronary vessel. Obviously, the need is for a drug that can lyse the thrombus - Treat to lyse the thrombus - thrombolytic agents like streptokinase, r-tpa (recombinant tissue plasminogen activator) are used.

This simplistic description should serve as a start to understand this complex disease and its more complex and sometimes controversial treatment options. If you have any specific questions, please feel free to ask here.