Anticoagulant, Antiplatelet, and thrombolytic agents Flashcards
1
Q
Define Anticoagulants?
A
Prevent blood clotting
2
Q
Define antiplatelet?
A
Inhibit platelet function
3
Q
Define Thrombolytics?
A
Dissolve formed clots
4
Q
Heparin mechanism?
A
- Accelerates inactivation by Antithrombin III.
- Thrombin bind irreversibly to Arg-Ser site on AT-III
- Heparin binding however is reversible
5
Q
Describe Anticoagulant use during pregnancy?
A
Discontinue 24h prior to induction of labor.
6
Q
Intramuscular Heparin injection is?
A
Contraindicated, induces painful hematoma.
7
Q
How do you monitor heparin?
A
Activated partial thromboplastin time (aPTT), monitors common and intrinsic pathway.
8
Q
Adverse effects of Heparin?
A
-
Bleeding
-
Thrombocytopenia Type 1
- Mediated by platelet-heparin interaction
- Treatment of excess hemorrhage
- Protamine sulfate: Heparin-protamine complex cannot bind to AT-III
-
Thrombocytopenia Type 1
9
Q
Benefit of low molecular weight heparin
A
-
Higher specificity for enhanced antithrombin III inactivation of Xa
- >5400 kDa or 18 monosaccharide units required to bind simultaneously AT-III and thrombin.
10
Q
Current perception of advantages for unfractionated heparin?
A
- Does not require monitoring; could monitor anti-Xa activity.
11
Q
Warfarin mechanism of action
A
- Inhibits hepatic synthesis of biologically active Vit-K-dependent clotting factors, Protein C and S.
12
Q
Warfarin therapeutic use?
A
- Drug of choice for oral anticoagulant
- Effective as an anticoagulant only when administered in vivo.
13
Q
How to monitor warfarin?
A
-
INR laboratory
- Monitor extrinsic pathway with prothrombin time.
14
Q
INR details and standards for thromboplastin
A
- International Normalized Ratio standardizes reagent thromboplastin to an international reference preparation (IRP) of thromboplastin
-
Goal for INR is 2.0-3.0
- Prophylactic for heart valves INR 2.5-3.0
15
Q
Adverse Rxns and Contraindications
A
- Hemorrhage
- Adverse rxns more likely to occur if:
- change in:
- Fibrin degradation
- Platelet function and #
- change in:
- Genetic predisposition
- CYP2C9 and VKORC1 genes
