Anticoagulants Flashcards
What is another name for an anticoagulant?
Blood thinner - but blood is not becoming thinner
What are the two purposes of anticoagulants?
- Decrease bloods ability to clot
- Help prevent or treat life-threatening conditions caused by a clot
Do most drugs help facilitate break down of existing clots or prevent clots from forming (or getting bigger)?
Prevent clots from forming (or getting bigger)
Most anticoagulation drugs do not preform what action?
Facilitate break down of existing clots
Anticoagulation drugs help to prevent or treat life-threatening conditions caused by a clot such as… (there are 4)
- Ischemic strokes
- Myocardial infarctions
- Pulmonary embolisms
- Venous thrombi
What are conditions that may cause blood clots?
- Atrial fibrillation
- Heart valve surgery/ replacement
- Joint replacement/ orthopedic surgery
- Blood clotting disorders
There are three kinds of drugs that affect blood clotting, what are they?
- Anticoagulants
- Antiplatelets
- Fibrinolytics (Thrombolytics)
What treats venous abnormal clot formation such as deep vein thrombosis (DVT) and thromboembolisms?
Anticoagulants
What is a thromboembolism?
A DVT (clot) that travels through the venous system to the right side of the heart and into the lungs to cause a pulmonary embolism
What prevents excessive clotting by inhibiting platelet activity?
Antiplatelets
What often forms by abnormal platelet aggregation?
Arterial thrombi
What is used to treat arterial clots such as coronary artery occlusions and cerebral infarctions?
Antiplatelets
What facilitates the breakdown and dissolution of already formed clots?
Fibrinolytics (Thrombolytics)
What converts plasminogen to plasmin to help break down fibrin?
Fibrinolytics (Thrombolytics)
What are the three ways of administration of anticoagulants?
- Parenteral
- Subcutaneous
- Oral
What is a parenteral anticoagulant and how is it administered?
- Heparin (prevents clots from getting larger)
- Through IV
What is a subcutaneous anticoagulant and how is it administered?
- Low molecular weight heparin
- Lovenox
- Arixtra
- Under the skin via needle
What is an oral anticoagulant and how is it administered?
- Vitamin K antagonist (Coumadin aka Warfarin)
- Administered through the mouth
Why is vitamin K so important when it comes to Coumadin (Warfarin)?
- Vitamin K aids in the clotting process
- Coumadin (Warfarin) takes vitamin K out of the problem
- Patient needs to be monitored for vitamin K ingestion as it is in most foods
- It takes hours to days to deplete the body’s stores of vitamin K
What is the preferred test for patient on vitamin K antagonist (VKA) such as Coumadin?
INR - International Normalized Ratio
What is INR?
Derived from prothrombin time - indirectly measures time it takes a sample of blood to clot through assessing level of several clotting factors
INR is a ratio, what is this ratio?
INR = patient PT / control PT
- (PT = prothrombin)
What is a normal INR and what does it mean?
- Normal = 1
- Takes the same time for patients blood to clot as it does for the control sample to clot
What is a therapeutic INR?
INR 2-3 = takes 2-3x as long to clot
If a patient has a high INR they are at risk for what?
Increased risk for uncontrolled bleeding
If a patient has a low (near 1) INR what does that mean?
They have an INR with no therapeutic effect
If someone has a high INR do they have a low vitamin K level or a high vitamin K level?
Low vitamin K level
What medication MUST you monitor INR with?
Coumadin/ Warfarin
There are newer anticoagulants called direct thrombin inhibitors, how are most of these administered?
Parenterally (IV or Subcutaneously)
What are some Factor Xa inhibitors and how are they administered?
- Fondaparinux (Arixtra): subcutaneous
- Apixaban (Eliquis): Oral
- Rivaroxaban (Xarelto): Oral
What prevents excessive clotting caused by increased platelet activity?
Antiplatelets
What are examples of antiplatelet drugs?
- Aspirin (most common)
- ADP receptor blockers
- Glycoprotein 2b-3b blockers
What are some adverse effects that antiplatelets can cause?
- Increased risk of bleeding
- GI irritation (with aspirin)
- Kidney and liver damage
Fibrinolytic agents (Aka clot busters) have what kind of time window to be the most effective?
Must be administered within a 3 hour window of symptom onset
What are the two kinds of fibrinolytic agents?
- Streptokinase
- TPA (Tissue Plasminogen Activator) (Alteplase)
What is the mechanism of action of Streptokinase?
- Nonenzymatic protein substance that forms a complex with plasminogen
- Converts plasminogen to plasmin
What can streptokinase be used for?
Lysis of acute DVT, pulmonary emboli, and acute arterial thrombi
What are the side effects of streptokinase?
Bleeding
How do you administer streptokinase?
Through an IV
What are the contraindications of streptokinase?
Bleeding, hemorrhagic stroke
What is the mechanism of action of TPA?
Recombinant human thrombolytic enzyme that activates plasminogen bound to fibrin
What can TPA be used for?
DVT, multiple pulmonary emboli
What are the side effects of TPA?
Bleeding
How do you administer TPA?
Through an IV
What are contraindications to TPA?
Bleeding and hemorrhagic stoke
