Anticoagulants Flashcards
Anistreplase class
Thrombolytics activate plasmin
3degree hemostasis
Anistreplase description
purified human plasminogen and bacterial streptokinase
Alteplase, Reteplase, Tenecteplase class
Thrombolytics activate plasmin
3 degree hemostasis
Alteplase, Reteplase, Tenecteplase description
recombinant t-PA
Less selective
Mutant t-PA
Alteplase, Reteplase, Tenecteplase mechanism
t-PA is a serine protease produced by human endothelial cells that activates plasminogen bound to fibrin (selective)
Alteplase, Reteplase, Tenecteplase indication
2nd line therapy after angioplasty for treatment of acute MI and ischemic stroke
Urokinase class
Thrombolytic
Urokinase description
Human enzyme synthesized in kidney
Urokinase mechanism
Direct conversion of plasminogen to plasmin
Urokinase indication
lysis of PE
Streptokinase class
Thrombolytic
Streptokinase mechanism
Catalyzes degradation of PF-V and VII in addition to activation of plasmin
Streptokinase description
Protein made by beta hemolytic strep
Streptokinase indication
Rarely used due to newer drugs
Warfarin description
Coumarin anti-coag
Monitor every 2-4 weeks via PT (INR)
Warfarin mechanism
Inhibits Vit K epoxide reductase -> can’t gamma carboxylate factors II, VII, IX and X
Factor VII is the first to go -> monitor PT
Can reverse action with Vit K (24 hrs)
Warfarin indication
Hypercoagulable states
Pregnancy category X
Warfarin PK
Oral
Several hours to take effect; single dose lasts for 2-5 days
Monitor with INR
Warfarin adverse
Narrow therapeutic window
Many drug interactions
Hemorrhage
Cutaneous necrosis** ->decreased activity of protein C -> paradoxical hypercoagulability
Lepirudin, Bivalirudin, Argatroban description
Direct thrombin inhibitors (hirudin from leeches)
Lepirudin, Bivalirudin, Argatroban mechanism
Direct binding to active site of thrombin
Inhibits thrombin and platelet aggragation
Lepirudin, Bivalirudin, Argatroban indication
Thrombosis related to HIT
Coronary angioplasty
Lepirudin, Bivalirudin, Argatroban PK
Parenteral
Monitored with PTT
Lepirudin, Bivalirudin, Argatroban adverse
No antidote
Fondaparinux description
synthetic pentasaccharide
Fondaparinux mechanism
Selective PF-10 inhibitor -> binds anti-thrombin III allowing it inhibit PF-10
Negligible ATIII activity
Fondaparinux indication
Treatment and prevention of DVT
Heparin, Enoxaparin, Dalteparin, Tinzaparin description
UFH: mixture of straight chain anionic GAGs
LMWH: has higher therapeutic index
Pentasaccharide sequence binds ATIII
Heparin, Enoxaparin, Dalteparin, Tinzaparin mechanism
UFH: binds to anti-thrombin III -> increased activity -> inhibits thrombin by forming a ternary complex along with factors IX and X
LMWH:inhibits factor X, with less of an effect on thrombin than UFH due to lack of ternary complex formation
Heparin, Enoxaparin, Dalteparin, Tinzaparin indication
DOC in pregnancy
DVT
PE
MI
Heparin, Enoxaparin, Dalteparin, Tinzaparin PK
Only given IV, never oral
Rapid acting
Monitored with PTT
Excess heparin is treated with protamine sulfate
Heparin, Enoxaparin, Dalteparin, Tinzaparin adverse
Bleeding
HIT (Type 2):
IgG binds to heparin/PF-4 complex -> binding to FcR on platelets ->degranulation and more PF-4 release -> thrombosis and thrombocytopenia
Tx. -> disocntinue use and give DTI or fondaparinux**
Abciximad mechanism
Irreversible monoclonal Ab
Eptifibatide mechanism
Reversible cyclic peptide antagonist
Tirofiban mechanism
Non peptide reversible antagonist
Abciximab, Eptifibatide, Tirofiban description
GPIIb/IIIa blockers
Platelet aggregation inhibitors
Abciximab, Eptifibatide, Tirofiban indication
Acute coronary syndrome
Angioplasty
give parentally
Abciximab, Eptifibatide, Tirofiban adverse
Patients who lack GPIIb/IIIa have Glanzmann’s Thrombasthenia
Dipyridamole, Cilostazol description
Platelet aggregation inhibitors
PDE inhibitor
Coronary vasodilation
Dipyridamole, Cilostazol mechanism
Increases cAMP
Little effect alone -> coadminister with aspirin or warfarin
Dipyridamole, Cilostazol indication
Prophylaxis for angina
Clopidogrel, Ticlopidine description
Platelet aggregation inhibitors
ADP receptor blockers
Clopidogrel, Ticlopidine mechanism
Irreversible inhibition of P2Y12 receptor on platelets -> decreased aggregation
Clopidogrel, Ticlopidine indication
Recent stroke, MI or acute coronary syndrome
Clopidogrel is preferred because is has fewer AE
Clopidogrel, Ticlopidine PK
Clopidogrel is a prodrug activated by CYP2C19 … DO NOT use with omeprazole which inhibits CYP2C19
Clopidogrel, Ticlopidine adverse
Inhibits CYP450
Thrombocytopenic purpura
Ticlopidine causes neutropenia
Aspirin description
inhibits platelet aggregation
COX inhibitor
Aspirin mechanism
Irreversible acetylation of COX -> blocks TXA2 synthesis -> prolonged bleeding time
TXA2 normally increases affinity for GPIIb/IIIa receptor to find fibrinogen
Aspirin indication
Cerebral ischemia
Stroke and MI
Aspirin PK
No nucleus = no new enzyme for 10 days