cofactor for the activation of antithrombin leading to decreased thrombin and factor Xa
Use of Heparin
immediate anticoagulation for PE, acute coronary syndrome, MI, DVT **Follow PTT
Heparin can be used during pregnancy bc...
it does not cross the placenta. Warfarin cannot be used in pregnancy.
Toxicity of Heparin
-bleeding -HIT -osteoporosis
For rapid reversal of Heparin, use...
protamine sulfate (which is a positively charged molecule that binds negatively charged heparin).
Low-molecular weight heparins (2)
1. Enoxaparin 2. Dalteparin
Low-molecular weight heparins act more on...
factor Xa, have better bioavailablity and 2-4x longer half life.
Heparin Induced Thrombocytopenia (HIT)
-development of IgG antibodies agaisnt heparin bound to platelet factor 4 (PF4) -Ab-heparin-PF4 complex activates platelets leading to thrombosis and thrombocytopenia
Argatroban, Bivalirudin MOA
Inhibit thrombin directly
Argatroban and Bivalirudin are used...
instead of heparin for anticoagulating pts with HIT.
-interferes with normal synthesis and gamma-carboxylation of vitamin-K dependent clotting factors II, VII, IX and X and proteins C and S
Warfarin is metabolized by...
In lab assays, Warfarin has an effect on the...
extrinsic pathways and increases PT.
Use of Warfarin
-chronic anticoagulation (after STEMI, venous thromboembolism prophylaxis, stroke prevention) **Follow PT/INR values.
Toxicity of Warfarin
-bleeding -teratogenic -skin/tissue necrosis
For reversal of warfarin overdose
-give vitamin K -if rapid reversal is necessary, give FFP
Apixaban and Rivaroxaban MOA
bind and directly inhibit activity of factor Xa
Use of Apixaban and Rivaroxaban
-treatment and prophylaxis of DVT and PE (rivaroxaban) -stroke prophylaxis
1. Alteplase (tPA) 2. Reteplase (rPA) 3. Tenecteplase (TNK-tPA)
MOA of thrombolytics (tPA, etc)
directly or indirectly aid conversion of plasminogen to plasmin, which cleaves thrombin and fibrin clots -increases PT and PTT
Use of thrombolytics
-MI -ischemic stroke -directy thrombolysis of severe PE
Thrombolytics are contraindicated in...
pts with active bleeding, hx of intracranial bleed, recent surgery, known bleeding diathesis or HTN.
Treat thrombolytic toxicity with...
aminocaproic acid (inhibitor of fibrinolysis).
irreversibly inhibits COX1 and COX2 by covalent acetylation; platelets cannot synthesize new enzyme so the effects last until new platelets are produced
-increased bleeding time -decreased TXA2 and prostaglandins -no effect on PT or PTT
Use of Aspirin
-antipyretic -analgesic -anti-inflammatory -antiplatelet (decreased aggregation)
Toxicity of aspirin
-gastric ulceration -tinnitus -reye syndrome in children with viral infxn
Chronic use of aspirin can lead to...
acute renal failure, interstitial nephritis and upper GI bleeding.
Overdose of aspirin causes....
respiratory alkalosis initially which is then superimposed by metabolic acidosis.