Exam 6 - Anticoagulant, Antiplatelet, and Fibrinolytic Drugs Flashcards
Warfarin
oral antigocagulant
Warfarin MOA
- inhibits synthesis of clotting factors II, VII, IX, X (2, 7, 9, 10)
- inhibits anticoagulant proteins C and S
- blocks vitamin K
Warfarin indications
- deep vein thrombosis (DVT)
- atrial fibrillation
- artificial heart valves
Warfarin goal
International normalized ratio (INR) 2-3
Warfarin pharmacokinetics
- metabolized by 2C9 (S), 2C19 (R), 1A2 (R), 3A4 (R)
- maximal effects not seen for 3 to 5 days
Warfarin adverse effects
Bleeding
- reversed by vitamin K
- Kcentra (Prothrombin Complex - factors II (prothrombin) VII, IX, X) - used w/ administration of vitamin K to reverse the anticoagulation effect and stop bleeding
- contraindicated in pregnancy
Polymorphism of 2C9 and VKORC1 (poor metabolizers)
will need lower dose
Warfarin interactions CYP 450 inducers
serum levels decreased by CYP 450 inducers (rifampin, carbamazepine, phenobarbital)
Warfarin interactions CYP 450 inhibitors
serum levels increased by CYP 450 inhibitors (amiodarone, azole antifungals, metronidazole, TMP/SMX
Warfarin (other) interactions
- aspirin, antiplatelets, NSAIDs, increase bleeding
- food containing vitamin K (can inhibit the action of warfarin)
Heparin MOA
- forms complex w/ antithrombin III
- irreversibly inactivates thrombin (factor IIa) and Xa
- HELPS PREVENT GROWTH AND EXTENSION OF THE CLOT BUT DOES NOT LYSE THE CLOT
Heparin indications
treatment and prevention DVT
Heparin adverse effects
- bleeding (reversed by protamine)
- Heparin Induced Thrombocytopenia (Type I HIT, Type II HIT; Type II HIT discontinue heparin)
- hyperkalemia (decreased aldosterone secretion)
- osteoporosis (long term use)
Heparin-induced thrombocytopenia (HIT-II)
- immune-mediated reaction
- platelets drop >50% or <100,000cells/mm3
- usually begins within 5-14 days but can begin immediately
- this is a HYPERCOAGULABLE STATE
Heparin
Parenteral anticoagulant
Enoxaparin MOA
inactivates clotting factors
- binds to antithrombin III (AT-III)
- LMWH-ATIII complex less affinity for thrombin
- primarily inactivates factor X
Enoxaparin
low molecular weight heparin (LMWH)
Enoxaparin is indicated for everything on the chart except
extended treatment for symptomatic VTE (venous thromboembolism) in cancer patients to reduce recurrence
Enoxaparin adverse effects
- spinal/epidural hematomoas
- DO NOT USE IN PATIENTS W/ TYPE II HIT (use a direct thrombin inhibitor such as Lepirudin or Bivalridin)
What is the comparison of UFH w/ LMWHs in regards to efficacy of antidote (protamine sulfate)
efficacy is only partial
Fondaparinux
parenteral anticoagulant
Fondaparinux MOA
indirect Xa inhibitor
Fondaparinux indications
prophylaxis of DVT in patients undergoing
- hip fracture and replacement surgery
- knee replacement surgery
- abdominal surgery
treatment of DVT and PE
Main difference between UFH, LMWH and Fondaparinux
Fondaparinux = no inactivation of thrombin
Fondaparinux pharmacokinetics
contraindicated in sever renal impairment
Fondaparinux adverse effects
bleeding - lack of antidote
Rivaroxaban
oral anticoagulant
Rivaroxaban MOA
oral direct Xa inhibitor
Rivaroxaban indications
- prophylaxis of DVT which may lead to pulmonary embolism in patients undergoing knee or hip replacement surgery
- treatment of DVT or PE and to reduce risk for recurrences after initial treatment
- prevention of stroke in AF w/ nonvalvular atrial fibrillation
- must be adjusted for renal function
Rivaroxaban adverse effects
spinal/epidural hematomas
- neuraxial anesthesia or spinal puncture
Rivaroxaban drug interactions
- drugs that inhibit 3A4 and P-gp (erythromycin and clarithromycin)
- drugs that induce 3A4 and P-gp (rifampin and phenytoin)
Dabigatran
oral anticoagulant
Dabigatran MOA
direct thrombin inhibitor
Dabigatran indication
reduce the risk of stroke and systemic embolism in patients w/ nonvalvular atrial fibrillation
Dabigatran pharmacokinetics
must be adjusted for renal function
Dabigatran adverse effects
bleeding and gastritis
Apixaban
oral anticoagulant
Apixaban MOA
oral factor Xa (thrombin) inhibitor
Apixaban indication
reduce the risk of stroke and systemic embolism in patients w/ nonvalvular atrial fibrillation
Lepirudin
parenteral anticoagulant; hirudin analogue
Bivalridin
parenteral anticoagulant; hirudin analogue
Hirudin analogue MOA
direct thrombin inhibitors
- does not cause HIT
- administered IV
Aspirin effects
- antipyretic
- analgesic
- anti-inflammatory
- antiplatelet
Aspirin MOA
inhibits thromboxane A2 (TXA2); IRRIVERSIBLY inhibits platelet aggregation for life of platelet
Aspirin indications
prevent thrombosis in
- coronary artery disease
- stroke/TIA (transient ischemic attack)
- peripheral arterial disease
Aspirin adverse effects
- GI bleeding
- tinnitus
- Reyes syndrome
Aspirin interactions
- warfarin
- anticoagulants
- NSAIDs
- these drugs interact w/ all antiplatelets
Dipyridamole
antiplatelet
Dipyridamole MOA
inhibits platelet aggregation
Dipyridamole indications
used in combination w/ ASA (Aggrenox); indicated for TIAs and stroke
Clopidogrel
antiplatelet
Clopidogrel MOA
irreversibly binds to platelet receptors
Clopidogrel pharmacokinetics
prodrug (metabolized to active drug by 2C19); inhibiting 2C19 may decrease effectiveness
Clopidogrel indications
- prevention of MI, strokes/TIA, peripheral arterial disease
- used alone or w/ ASA in ACS (acute coronary syndrome which can be STEMI or NSTEMI)
Clopidogrel adverse effects
- bleeding
- thrombotic thrombocytopenic purpura
What should be used if a patient is allergic to aspirin?
Clopidogrel
Prasugrel
antiplatelet
Prasugrel MOA
irreversibly binds to platelet receptors
Prasugrel indications
- reduction of thrombotic cardiovascular events (including stent thrombosis) IN PATIENTS W/ ACUTE CORONARY SYNDROME WHO ARE TO BE MANAGED W/ PCI AS FOLLOWS:
- patients w/ unstable angina or non-ST-elevation myocardial infarction (NSTEMI)
- patients w/ ST-elevation myocardial infarction (STEMI) when managed w/ either primary or delayed PCI
Prasugrel adverse effects
bleeding
Prasugrel contraindications
prior transient ischemic attack or stroke; generally not recommended for patients or are 75 years or older
Ticagrelor
antiplatelet
Ticagrelor MOA
REVERSIBLY bind to platelet receptor
Ticagrelor indications
- reduce the rate of thrombotic cardiovascular events in patients w/ acute coronary syndrome (ACS) (unstable angina, non-ST elevation myocardial infarction, or ST-elevation myocardial infarction)
- always used w/ aspirin
Ticargrelor contraindications
- history of intracranial hemorrhage
- active pathological bleeding
Ticagrelor warnings and precautions
- avoid maintenance doses of aspirin above 100 mg
- dyspnea
Ticagrelor adverse effects
- bleeding (12%)
- dyspnea (14%)
Ticagrelor drug interactions
avoid strong 3A4 inhibitors and inducers
Abciximab
antiplatelet; glycoprotein IIb/IIIa antagonist
Abciximab MOA
prevents aggregation by binding to GP IIb/IIIa receptor; prevents fibrinogen binding and cross-linking of platelets
Abciximab indications
percutaneous coronary interventions
Abciximab adverse effects
- bleeding
- hypotension
- bradycardia
- thrombocytopenia
Tirofiban
antiplatelet; glycoprotein IIb/IIIa antagonist
Eptifibatide
antiplatelet; glycoprotein IIb/IIIa antagonist
Tirofiban and Eptifibatide MOA
prevents aggregation by binding to GP IIb/IIIa receptor; prevents fibrinogen binding and cross-linking of platelets
Tirofiban and Eptifibatide indications
- percutaneous coronary interventions
- ACS (acute coronary syndrome)
Tirofiban and Eptifibatide adverse effects
bleeding
Alteplase
fibrinolytic/thrombolytic
Reteplase
fibrinolytic/thrombolytic
Tenecteplace
fibrinolytic/thrombolytic
How are fibrinolytic drugs given?
given IV
Fibrinolytic/thrombolytic MOA
- thrombolytics are enzymes that convert plasminogen to plasmin
- plasmin degrades fibrin and fibrinogen causing clot dissolution
Fibrinolytic/thrombolytic drugs adverse effects
hemorrhage
Fibrinolytic/thrombolytic drugs interaction
increase bleeding associated w/ anticoagulants and antiplatelets