Recall that plasmin is the enzyme in the body responsible for breaking down clots and that plasminogen is the inactive form of plasmin.
- Tissue plasminogen activator (tPA): In the body, tPA is the enzyme responsible for the conversion of plasminogen to plasmin. Alteplase is a pharmacologic tPA and functions in the same way.
- Streptokinase: Streptococci produce this substance. When given as a drug, streptokinase works with the body's own supply of plasminogen. Plasminogen, in the presence of streptokinase, will become plasmin at a fast rate. NOTE: This drug is still discussed in literature but is no longer available in the US.
Use of thrombolytics:
- Stroke patients who do not have any brain bleeding: thrombolytic use within three hours is indicated and improves outcomes after a stroke. Note that thrombolytics are NOT used in stroke patients who have a "bleeding" or hemorrhagic stroke, as the administration of thrombolytics will increase bleeding in the brain.
- Myocardial infarction: Thrombolytics can play a role in an open thrombosed coronary artery if a patient is at a hospital that doesn't have the ability to perform heart catheterization procedures.
Toxicity of thrombolytics:
- With any drug that breaks down clots, you would be concerned about hemorrhage.
