Hemostasis Modifier Drugs - Ch. 55 Flashcards
What is hemostasis?
Process that halts bleeding after injury to a blood vessel
1. Forms a platelet plug
2. Fibrin produced (clotting cascade, plasma proteins)
What are hemostasis modifier agents?
Anticoagulants
Antiplatelet drugs
Thrombolytic drugs
Hemostatic agents
What do anticoagulants do?
Inhibit the action or formation of clotting factors
Prevent clot formation
What do anti platelet drugs do?
Inhibit platelet aggregation
Prevent platelet plugs
What do thrombolytic drugs do?
Lyse existing clots
What do hemostatic agents do?
Promote blood coagulation
What is the final product of the clotting cascade?
Fibrin
What is the clotting/coagulation cascade divided into?
Intrinsic pathway
Extrinsic pathway
What is the other name for anticoagulants?
Blood thinners
How are anticoagulants used?
Prophylactically
What are anticoagulants used to prevent?
Clot formation (thrombus)
Emboli (dislodged clots)
What are anticoagulants not used for?
Do not use to lyse/break down existing clots
In what settings are anticoagulants used to prevent clot formation?
MI
Unstable angina
Atrial fibrillation
DVT e.g, major orthopaedic surgery
Indwelling devices (e.g, mechanical heart valves)
Pulmonary embolism
Examples of anticoagulants that all prevent clot formation?
Heparin and low molecular weight heparins (LMWH)
Warfarin -oral
Direct-Acting Oral Anticoagulants (DOACs)
-Direct factor X & Thrombin inhibitors
When is anticoagulant use contraindicated?
Known drug allergy
Acute bleeding process
Thrombocytopenia
What adverse effects are associated with anticoagulants?
Bleeding risk
-gums bleed
-nosebleeds
-unusual bruising
-anemia/low Hct
-tarry stools
What is the mechanism of action of Heparin?
Indirectly inhibits activity of multiple proteins on cascade
What proteins are inhibited by heparin?
-Thrombin (II)
-Factor Xa
-Intrinsic pathway factors
What is natural heparin?
Obtained from animal sources
how is heparin monitored because of its unpredictable dosage?
Activated partial thromboplastin times (aPTT)
What pathway does aPTT measure?
Intrinsic pathway
What do aPTTs need to be?
1.5 - 2.5 x greater than 40 sec (control)
How is Heparin administered?
Parenteral (IV or SC)
How long does it take for Heparin to be effective?
Seconds
What is the half life of Heparin?
Short half life
1-2 hours
What adverse effects are associated with Heparin?
Heparin-induced thrombocytopenia (HIT)
Hypersensitivity reactions
What is Heparin-induced thrombocytopenia (HIT)?
The body reacts to heparin in a way that causes platelets to clot instead of preventing them
-Increases blood clots
-1-5% population (>4 days of administration)
-stop heparin administration and use an alternative
What hypersensitive reactions does Heparin cause?
Urticaria
Fever
Chills
What is the antidote for heparin?
protamine sulfate
What does protamine sulphate do?
Reverses anticoagulant effects