Thrombolytics / Contraindications
Thrombolytics: STREPTOKINASE, UROKINASE,
TISSUE PLASMINOGEN ACTIVATORS (ALTEPLASE, RETEPLASE, TENECTEPLASE)
Common contraindications
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The fundamental problem with the action of thrombolytics is that they don't distinguish between "good" clots (such as the hemostatic plug shown here) and "bad" clots (thrombi). Thrombolytic drugs will degrade fibrin wherever it is found. |
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- cause BLEEDING (particularly hemorrhagic stroke)
- at physiologic levels, tPA has significant clot specificity, because plasminogen and plasmin have specialized protein domains (kringles) that bind to the clot and because the activity of tPA is regulated by plasminogen activator inhibitor (PAI)
- however, at pharmacologic concentrations, this innate inhibitory control system can be overwhelmed producing a systemic lytic state è these drugs are not for use in patients with:
- recent surgery (10 days)
- active bleeding or hemorrhagic disorder
- previous cerebrovascular accident or active intracranial process
- history of hypertension (diastolic > 110 mg Hg)
- GI bleeding (in the last 3 months)
- pregnancy
- aortic dissection
- acute pericarditis
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thrombolytics can be antagonized by AMINOCAPROIC ACID (for tPAs) or APROTININ (for STREPTOKINASE)
- thrombolytic therapy is expensive (particularly tPAs)
- differences in cost among these agents is a major factor in treatment decisions