Part 8-2 Cardiovascular Pharmacology Flashcards
Coagulation disorders
- Inadequate clotting: hemorrhage
- Excessive clotting: thrombogenesis
Clotting Mechanism Intrinsic System
Begins when factor XII contacts damaged vessel
Clotting Mechanism Extrinsic system
Begins when damaged vessel releases tissue factor (Thromboplastin)
Clotting Mechanism sequence
CF XII and CF VII lead to CF X
CF X turns prothrombin into Thrombin
Thrombin turns fibrinogen to Fibrin
Clot Breakdown
Tissue Plasminogen Activator turns plasminogen into plasmin
Drugs for overactive clotting
Anticoagulants
Antithrombotics
Thrombolytics
Anticoagulants
Used primarily in venous thrombosis
- Heparin
- Oral anticoagulants
Heparin
Acts by increasing effects of antithrombin III
- rapid effects
- Administered parenterally
Types of heparin
Unfractionated heparin
Low molecular weight heparins
Unfractioned heparin
- IV administration, several injections per day
- Unpredictable effects
Low molecular weight heparins
Administered sub-Q, usually 1/day
Preferentially inhibit factor Xa
More predictable, safer effect
Heparin induced thrombocytopenia
Heparins can decrease platelets
Type I HIT
Type II HIT
Type I HIT
Asymptomatic, resolves spontaneously
Type II HIT
Immune reaction…causes serious thrombosis, life/limb threatening
Oral anticoagulants
Warfarin (Coumadin)
Dicumarol
-Inhibit vitamin K function in liver
-Decreased synthesis of certain clotting factors
Oral anticoagulants administration
Oral administration
Time lag of 3-4 days
Typically used after heparin
Other Anticoagulants
Can be used as primary or if other anticoagulants aren’t tolerated
Other anticoagulant examples
Direct Thrombin inhibitors
Factor Xa Inhibitors
Antithrombotics
-Inhibit platelet activity; decrease platelet induced clot
Primary agents
-aspirin
-Newer antiplatelet drugs
Aspirin anticlotting effects
- Aspirin inhibits PG & Thrombozane (TX) biosynthesis
- Decreased TXs means less platelet induced clots