IV Thrombolytics

Question 1

When are these used?

Answer 1

Acute myocardial infarction (STEMI/NSTEMI)
PE/DVT
Phrophylaxis of clot formation - post surgery, pregnancy, after giving birth, immobile

Question 2

Plasminogen activators

Answer 2

Streptokinase, alteplase, tenecteplase and retaplase

Urokinase can be used to restore the patency of occluded intravenous catheters and cannulas blocked with fibrin clots

Question 3

Glycoprotein IIb/IIIa inhibitors

Answer 3

Prevent platelet aggregation and thrombus formation by inhibiting GpIIb/IIIa on platelet surface
- Without the inhibitor, fibrinogen would interact with platelet surface and convert to fibrin

Question 4

Heparin

Answer 4

Binds to antithrombin III which inactivates thrombin, factor Xa and other proteases
Unfractionated has a short half life so should be stopped with immediate effect

Question 5

Low MW heparin

Answer 5

Has a longer half life, high absorption and high bioavailibility
Subcutaneous injection
Forms a complex with antithrombin III inhibiting several clotting factors

Dalteparin, enoxaparin, tinzaparin

Question 6

How to monitor

Answer 6

For unfractionated monitor: platelets and activated partial thromboplastin time (aPTT)
For low MW heparin: Factor Xa levels

Question 7

Heparin induced thrombocytopenia

Answer 7

Low platelet count due to administration of heparin
More common with unfractionated
Argabotran is used to treat this