Streptokinase (Streptase) (Last Updated - 4/6/2005)
-produced by beta-hemolytic strep
-no intrinsic enzymatic activity on its own
-Mechanism Of Action:
-forms complex w/ plasminogen --> induces plasminogen --> plasmin
-NO fibrin (Ia) specificity (unlike t-PA) --> increased risk of serious hemorrhage
-Dosing:
-Loading Dose: 250,000 units (2.5 mg) IV
-to overcome plasma Ab's against it due to prior strep infex.
-1/2-Life:
-40-80 mins. (once Ab's are depleted)
-NOT inhibited by alpha-2-anti-plasmin
-Uses:
1) Acute MI --> coronary thrombolysis --> DOC
-Side Effex:
1) Serious hemorrhage --> NO fibrin (Ia) specificity --> no limit to systemic plasmin formation
2) Allergic reax. (Ex.) anaphylaxis --> rare)
3) Fever
-t-PA vs. Streptokinase:
-t-PA (plus Aspirin) vs. Streptokinase (plus Aspirin) for Acute MI's:
-PTCI (Percutaneous Transluminal Coronary Intervention) is still superior to either
-NO statistically significant differences
-both t-PA & Streptokinase (both along w/ Aspirin) decreased death & reinfarction rates by ~30%
-t-PA more expensive than Streptokinase (Streptase)
-Streptokinase (Streptase) --> DOC (unless pt. has already received it in the past --> increased Ab titers --> then t-PA is DOC
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References:
Goodman & Gilman's: The Pharmacologic Basis Of Therapeutics - 10th Edition - 2001. Chapter 55.