Coagulation Modifier drugs Flashcards
What is hemostasis
General term for any process that stops bleeding
What does coagulation mean
The process of blood clot formation
What is the difference between a thrombus and an embolus
Thrombus is a blood clot
Embolus is a blood clot that moves through blood vessels
What is the cascading effect of coagulation
Each activated factor serves as a catalyst that amplifies the next reaction
What is the result of the coagulation system
Fibrin, a clot forming substance
What is the purpose of the fibrinolytic system
Initiates the breakdown of clots and balances the clotting process to prevent blood vessel blockage
How does fibrinolysis occur
Fibrin in the clots bind to plasminogen
Binding converts plasminogen to plasmin
Plasmin is an enzyme that eventually breaks down thrombus into fibrin degradation products
This keeps the thrombus localized and prevents it from becoming an embolus
What is hemophilia and what are the 2 types
A genetic disorder in which natural coagulation and hemostasis factors are limited or absent
Factor VII deficient
Factor VIII and/or IX deficiency
What are the 5 categories of coagulation modifiers ?
Anticoagulants
Antiplatelets
Hemorheological drugs
Thrombolytic drugs
Antifibrinolytic/hemostatic
How do anticoagulants prevent clot formation
They don’t affect clots that have already been formed
Prevents thrombosis by decreasing blood coagulability
Used prophylactically to prevent embolus and thrombus
What are the different types of thromboembolic events
Embolus in coronary artery: MI
Embolus in brain: Stroke
Embolus in lungs: Pulmonary embolus
Embolus in leg veins: DVT
What is the MOA of heparin anticoagulants
Inhibit clotting factors IIa(thrombin), Xa and IX
XI and XII also inactivated but not as important
Name an example of an unfractionated heparin and low-molecular weight heparin (LMWH)
Heparin and Enoxaparin
What requires more frequent lab monitoring of bleeding times? LMWH or Unfractionated Heparin
Unfractionated Heparin. It is not needed for LMWHs
When are the indications for heparin
Prevention of clot formations
Used as bridge therapy for patients to stop warfarin after surgery
What does warfarin do?
Inhibits vitamin K synthesis in the GI
This impairs the synthesis II, VII, IX and X
Prevents clot formation
How do antithrombin medications work and name one
Directly inhibit thrombin (factor IIa)
Dabigatran (synthetic)
T/F: Dabigatran has no antidote even though it has the most severe adverse effects
True
Name a direct acting Xa inhibitor
Rivaroxaban
What are the indications for anticoagulants
MI
Unstable angina
Atrial fibrillation
Conditions in which blood flow may be slowed and blood may pool
What are the contraindications of anticoagulants
Acute bleeding or high risk of bleeding
Pregnancy
Epidural catheters with LMWHs for risk of epidural hematoma
What are the adverse effects of anticoagulants
Increased bleeding time
Abdominal cramps
Lethargy
Muscle pain
Skin necrosis
Purple toes
Thrombocytopenia
What is heparin-induced thrombocytopenia (HIT) and what are the two types
Deficiency of platelets in blood
Type 1: Gradual reduction in platelets
Type 2: Acute reduction in platelets( >50% of baseline)
T/F: Discontinue heparin therapy for Type 1HIT and continue heparin therapy for type 2 HIT
False: Discontinue for Type 2 and Continue for Type 1
How can HIT be treated
Using thrombin inhibitor argatroban
What are the symptoms of heparin toxicity
Hematuria
Melena (blood in stool)
Petechiae (red spots)
Ecchymoses (bruising)
What is the purpose of IV protamine sulphate
Treat heparin toxicity
1 mg of protamine can reverse the effects of 100 units of heparin (1mg of protamine for each mg of LMWHs)
What is used to reverse warfarin toxicity
Vitamin K1(phytonadione)
How long does it normally take for the liver to resynthesize enough clotting factors to reverse the effects of warfarin? And how does Vitamin K1 affect this ?
36 - 42 hours
Vitamin K1 can return normal coagulation within 6 hours if given a high dose through IV (10 mg)
What are some risks associated with giving Vitamin K IV
Warfarin resistance will occur for up to 7 days
Risk for anaphylaxis (decreased by diluting and giving every 30 mins)
What is heparin sodium used for and what is the route, dosage and frequency?
DVT prophylaxis
5000 units SQ BID or TID
Does not need to be monitored when used for it.
What are heparin flushes used for and what is a risk?
Used to flush IVs and central catheters
Risk of development of HIT so most places use saline as a flush for IVs instead.
What is the most commonly used oral anticoagulant
Warfarin sodium
Name 3 antiplatelet drugs and what do they do
Aspirin
Clopidogrel bisulfate
Eptifibatide
Prevent platelet adhesion at the site of injury, which occurs before the clotting cascade
How does aspirin prevent platelet adhesion and what is it used for
Inhibits cyclooxygenase in platelet which prevents TXA2 (causes platelet aggregation and vasoconstriction)
May affect vitamin K dependent clotting factors
Used for stroke prevention and MI
How does clopidogrel prevent platelet adhesion and what is it commonly used as
Alters platelet membrane so that it can no longer receive signal to aggregate and form platelet plug
Most commonly used as an ADP inhibitor
T/F: Aspirin is better than clopidogrel at reducing number of MI’s, strokes and vascular deaths for at risk patients
False: Clopidogrel is better
How does Eptifibatide prevent platelet adhesion and where is it usually used
Inhibits GP II/IIa
Usually used in critical care or cardiac catheterization settings where continuous cardiac monitoring is available
Eptifibatide is only available for __________
IV infusion
What are the adverse effects of antiplatelets
All pose a risk for serious bleeding episodes
What are the contraindications of antiplatelets
Vitamin K deficiency, leukemia, thrombocytopenia
Name 2 thrombolytic drugs and what they do
Alteplase
Tenecteplase
Breakdown already formed clots
What is the MOA of thrombolytic drugs
Activates fibrinolysis to break down the clot quickly
Activates plasminogen and converts it to plasmin which lyses thrombus
Mimics body’s process of clot destruction
What are the indications for thrombolytic drugs
Acute MI
Arterial thrombolysis
DVT
Occlusion of shunt/catheter
Pulmonary embolism
Acute ischemic stroke
What are the adverse effects of thrombolytic drugs
Increased bleeding
Hypotension
Anaphylactoid reactions (mimic allergic reaction but not caused by immune response)
Cardiac dysrhythmias
What is the purpose of antifibrinolytic drugs
Prevents the lysis of fibrin so it promotes clot formation
What are the indications of antifibrinolytic drugs
Used to prevent and treat excessive bleeding
Treats hemophilia A
Treats type 1 Willebrand’s disease with desmopressin
Name an antifibrinolytic drug
Desmopressin (DDAVP)
What are the adverse effects of antifibrinolytic drugs
Dysrhythmia
Orthostatic hypotension
Bradycardia
Headache
Dizziness
Hallucinations
Fatigue
Abdominal cramps
Diarrhea
T/F: Do not give SQ doses of heparin within 5 cm of umbilicus, abdominal incisions, open wounds, scars, drainage tubes, stomas, or areas of bruising or oozing
True
Why shouldn’t you massage the injection site or aspirate SQ injections of heparin
May cause hematoma to form
T/F: Anticoagulant effects from heparin are seen immediately whereas warfarin effects take several days
True
What is the antidote for excessive coagulation from heparin
Protamine sulphate
What herbal products interact with warfarin to cause increased bleeding
Capsicum pepper
Garlic
Ginger
Ginkgo
St. John’s wort
Feverfew
What type of diet should patients have when taking anticoagulants
Low vitamin K (avoid tomatoes, dark leafy green veggies)
What are the signs of internal bleeding
Decreased BP, restlessness, increased pulse
