II. Indications
III. Mechanism
- Tissue Plasminogen Activator (tPA)
- Serine protease binds Fibrin and activates Fibrin-bound plasminogen to plasmin
- Plasmin breaks down both Fibrin and Fibrinogen to Fibrin
- Fibrin Degradation Products result, which in turn also act to inhibit Fibrin formation
- tPA has been replaced by recombinant products (r-tPA)
- tPA was originally synthesized and extracted from cultured mammalian cells
- Recombinant Tissue Plasminogen Activator (r-tPA)
IV. Dosing
-
Myocardial Infarction
- See Thrombolysis in ST Elevation Myocardial Infarction
- Bolus: 15 mg IV THEN
- Next: 0.75 mg/kg (max 50 mg) over 30 minutes THEN
- Next: 0.5 mg/kg (max 35 mg) over next 60 minutes
- Administer adjunctive Heparin concurrently
- See Thrombolysis
- Acute Ischemic Cerebrovascular Accident
- See Thrombolysis in Cerebrovascular Accident
- Calculate total dose: 0.9 mg/kg (max 90 mg)
- Bolus: Give 10% total dose as IV bolus over 1 minute
- Next: Give remainder of total dose over 60 minutes
- Acute Massive Pulmonary Embolus
- See Thrombolysis in Massive Pulmonary Embolism
- Pulse present
- First: 10 mg IV bolus
- Next: 90 mg IV over 2 hours
- Pulse absent
- tPA 50 mg IV bolus and continue CPR for at least 30 minutes (to allow for tPA circulation)
- Restart Heparin when PTT below twice normal
- Occluded central venous access
- Administer 2 mg/ml via occluded catheter for 2 hours
- May repeat once if refractory to first dose
V. Efficacy
- Disadvantages (compared with other Thrombolytics)
- Increased bleeding risk
- 3-4% greater risk of bleeding in older than age 75
- Re-occludes earlier than other Thrombolytics
- Needs Heparin concurrently and afterward
- Increased bleeding risk
- Advantages (compared with other Thrombolytics)
- Probably reperfuses arteries earlier
- Superior in large, anterior Myocardial Infarctions
VI. Safety
- Unknown safety in pregnancy
- Unknown safety in Lactation
VII. Drug Interactions
-
ACE Inhibitor
- Increased Angioedema risk when tPA is used