12. Antithrombotics and Thrombolytics Flashcards
1
Q
- The body normally maintains an equilibrium between which 2 mechanisms in relation to hemostasis?
- Why is the blood clotting mechanism essential? (2)
- Hemostasis involves which 3 important factors?
A
- Clot formation (thrombosis) and Clot breakdown (fibrinolysis)
- Prevents blood loss and Repairs damaged vessels
- platelet membrane phospholipids, calcium , and activation of protein coagulation factors
2
Q
- Complex biochemical reactions leading to clotting are initiated via which 2 cascade pathways?
- Extrinsic pathway is the ____ factor pathway. Therefore, factors are located where?
- What does this pathway initiate?
A
- Extrinsic and Intrinsic
- tissue –> located outside the plasma
- coagulation during hemostasis
3
Q
- The Intrinsic pathway of clotting involves factors that are located where?
- This pathway is called the ______ ________ pathway.
- How is this pathway activated?
A
- present within the plasma
- contact activation pathway
- by trauma or infection
4
Q
- What happens to the Intrinsic and Extrinsic pathways prior to forming a blood clot?
- What 2 factors act as a catalyst for prothrombin –> thrombin?
- What does thrombin catalyze? What does this end up activating?
- What is the end product of this whole cascade pathway?
A
- they will merge into a final common pathway
- activated factor X (Xa) + calcium
- fibrinogen’s conversion to fibrin activating fibrin stabilizing factor
- stable fibrin clot
5
Q
- With maintaining hemostasis, there is eventual activation of the fibrinolytic system, how?
- From the previous question, plasminogen –> plasmin, what does this lead to?
- What are antithrombotic agents?
- How are the different class of antithrombotic agents classified?
A
- by tissue plasminogen activator (t-PAs)
- Dissolves fibrin and fibrinogen to dissolve clot
- agents that prevent or break up blood clots
- according to MOA
6
Q
- What are the 3 classes of antithrombotic agents?
- What 2 things do anticoagulants prevent?
- What do antiplatelets do?
- What do thrombolytics do?
- Out of the above medications, which is the only one capable of breaking up a clot already formed?
A
- Anticoagulants, Antiplatelets, and Thrombolytics
- prevent the formation of fibrin clots and further clot formation in pre-existing thrombi
- inhibit platelet action at the onset of clotting
- break up thrombi through fibrin degradation
- thrombolytics! - others are for prophylaxis
7
Q
- What type of drug is Heparin?
- This native substance is found where? What can this drug be extracted from? (2)
- What is the name of natural heparin? What does this mean? What does this lead to?
A
- anticoagulant
- in mast cells, can be extracted from bovine lung or porcine intestines
- unfractionated heparin (UFH) meaning it varies in length and molecular size leading to less predictable treatment
8
Q
- What are the 4 traditional indications to using Heparin?
- What are the 3 novel indications for using this drug?
- What are 3 contraindications?
- What are 2 adverse effects?
A
- Prevention and treatment of VTE (DVT), PE & peripheral arterial embolism, Treatment of Afib with embolization (blood can become stagnant), Treatment of DIC, and Prevention of clot formation in invasive lines
- ARDS, inhalational injuries, and allergic responses
- Pre-existing bleeding disorders, Recent surgery, Active bleeding sites
- osteoporosis and heparin induced thrombocytopenia (HIT)
9
Q
- What drug is known as the heparin antidote?
- MOA? (2)
- Where in the hospital is this drug often used? why?
A
- Protamine (reversal agent)
- Combines with free heparin forming inactive salt and Also dissociates heparin-antithrombin III complexes
- OR’s to maintain hemostasis and decrease bleeding during surgery
10
Q
- What is the dose when using Protamine? What is the maximum amount that can be given?
- A slow IV infusion over 1-3 minutes is recommended to prevent what 3 effects?
- This drug poses a risk of allergic anaphylactic reaction in which patients? (3)
A
- 1 mg for every 100 U of heparin, up to 50 mg
- hypotension, bradycardia, and dyspnea
- Patients receiving insulin that contains protamine, Vasectomy patients, and Patients with fish sensitivity*
11
Q
- What is the other drug name for Enoxaparin? For Dalteparin?
- What type of drug class are these?
- These drugs are considered ____ _______ _______ heparin. These drugs consist of what type of molecular chains?
- When are these drugs typically prescribed?
A
- Lovenox and Fragmin
- Anticoagulant agents
- low molecular weight heparin (LMWH) consisting of polysaccharide chains (uniform in length/size)
- mostly out-patient therapy (becoming the standard of care)
12
Q
- What are 4 additional advantages of LMWH such as Enoxaparin and Dalteparin?
- What are the 7 indications? (same as heparin)
- What are the 2 contraindications?
A
- OD dosing, ↑ half-life and bioavailability, SC administration, ↓ risk of osteoporosis and HIT
- Prevention and treatment of VTE (DVT), PE & peripheral arterial embolism, Treatment of Afib with embolization, Treatment of DIC, Prevention of clot formation in invasive lines, ARDS, Inhalational injuries, and Allergic responses
- Pre-existing bleeding disorders, and End-stage renal disease
13
Q
- What is the other drug name for Fondaparinux?
- What type of drug is this?
- This drug is a synthetic derivative of?
- What does this drug inhibit? And causes indirect suppression via?
A
- Arixtra
- anticoagulant
- heparin
- factor Xa inhibitor, and causes indirect suppression via ATIII
14
Q
- Regarding Fondaparinux, a daily SC injection is used to treat? (2)
- Fondaparinux has a better safety profile then which 2 types of heparin?
- What are the 3 adverse reactions of this drug?
A
- Deep vein thrombosis (DVT) and pulmonary embolism
- UFH and LMWH
- bleeding, low risk of osteoporosis and HIT
15
Q
- What is the other drug name for Rivaroxaban?
- What type of drug is this?
- Is a direct inhibitor of? Interferes with?
A
- Xarelto
- anticoagulant
- factor Xa and interferes with final common pathway
16
Q
- How is this drug taken? why?
- Rivaroxaban is partially cleared by the ______.
- This drug was approved for prevention of?
A
- by mouth - orally active
- kidneys
- VTE following hip/knee replacement surgery
17
Q
- Direct thrombin inhibitors (anticoagulant drugs) will inhibit?
- less likely to cause?
- What are 2 indications for using this class of drugs?
- This class of anticoagulants are called ____ group of drugs. Polypeptide found where? Example?
A
- prothrombin enzyme (factor IIa)
- bleeding complications
- HIT and acute coronary syndrome
- Hirudin –> found in salivary glands of leeches
ex. / dabigatran (pradaxa) used in ortho patients
18
Q
- What is the other drug name for Warfarin?
- What type of drug is this?
- MOA?
- suppresses which 4 key coagulation factors?
A
- Coumadin
- Anticoagulant
- synthetic vitamin K antagonist –> inhibits enzyme that activates vit K
- VII, IX, X, and prothrombin?
19
Q
- Where is Warfarin active? Where is it rapidly absorbed in the body?
- This drug has a delayed? how long? how long till therapeutic effect is reached?
- What are 2 indications?
A
- orally active, rapidly absorbed by the gut
- onset of action (1-3 mins) –> 1 week for full therapeutic effect
- Prevention and treatment of DVT, and Superwarfarins used as rat poisons (make the rat bleed out)
20
Q
- What are the 3 contraindications for using Warfarin? (same as heparin)
- What are the 3 precautions?
- What drugs increase the effects of warfarin? (6)
A
- Pre-existing bleeding disorders, Recent surgery, and Active bleeding
- Bleeding, Unpredictable pharmacodynamics, and Significant drug and food interactions
- Antibiotics, NSAIDs, Loop diuretics, GERD agents, Statins, and Antifungal agents
21
Q
- What drugs decrease the effects of warfarin? (6)
2. What foods decrease the effects of warfarin? (7)
A
- Oral contraceptives, Rifampin, Barbiturates, Spironolactone, Thiazide diuretics, and vitamin K
- Liver, Broccoli, Brussel sprouts, Leafy green veggies, Cranberry and grapefruit juice, Mango, and Soy products
22
Q
- Platelet aggregation is important for?
- Normally, which cell surface is anticoagulated?
- What happens when the above cell surface is disrupted? (3)
A
- controlling ruptured vessels
- endothelial surface
- procoagulant subendothelium exposed, chemotactic factors released–> promoting platelet aggregation
23
Q
- What are the 4 categories of antiplatelet drugs?
- What is the other drug name for Acetylsalicylic acid?
- What type of drug is this?
A
- COX inhibitors, ADP receptor antagonists, Prostaglandin analogues, and Glycoprotein IIb/IIa inhibitors
- Aspirin
- antiplatelet drug
24
Q
- What pathway does Aspirin act on? What does this inhibit?
- What are the 3 indications to using this drug?
- What is the other drug name for Clopidogrel?
A
- arachidonic acid pathway –> inhibits COX-1 enzyme
- Thromboprophylaxis, Low dose therapy (81 mg) daily for cardiac pts, and Useful in areas with high shear rates (vessel stenosis and atherosclerotic plaques)
- Plavix
25
Q
- What type of drug is Clopidogrel?
- What type of inhibitor is this drug?
- What does this drug decrease?
- When is this drug indicated?
- Useful for patients who?
A
- antiplatelet drug
- ADP receptor inhibitor
- platelet aggregation
- for CVA (stroke)
- can’t tolerate ASA
26
Q
- What do thrombolytic drugs induce? Which 3 locations in the body especially?
- What do this class of drugs help to convert? Therefore these drugs are also called?
- MOA?
- These drugs have an effect in reducing?
A
- fibrinolysis of life threatening clots - especially pulmonary, coronary and cerebral
- Plasminogen –> plasmin and also called plasminogen activators
- degrade fibrin without releasing thromboemboli
- infarct size
27
Q
- What is sensitive about thrombolytic agents? Typically given within?
- When are thrombolytics preferred over PCI? (2)
- Thrombolytics decrease the incidence/severity of? (2)
A
- administration is time sensitive –> given within 12-24 hours of symptoms
- if STEMI patient presents to hospital within 3 hours of symptom onset and door to primary PCI time > 90 mins
- CVA’s and MI’s
28
Q
Thrombolytic agents have 9 contraindications, can you list a few?
A
- History/evidence of ICH (intracranial hemorrhage)
- SAH (subarachnoid hemorrhage)
- Known AV malformation: arteries and veins do not connect normally, increasing pressure and chances of bleeding
- SBP > 185 mmHg or DBP > 110 mmHg
- Seizure with postictal neurological impairment
- Platelet < 100,000/mm3
- INR > 1.7
- Active internal bleeding/trauma
- Head trauma/stroke within 3 months
29
Q
- What is the other drug name for Streptokinase?
- What type of drug is this?
- This drug was derived from?
A
- Streptase
- thrombolytic agent
- Streptococcal virulence factor
30
Q
- What are the 4 precautions to using Streptokinase?
- What are the 2 adverse effects?
- This is the preferred thrombolytic for patients how old? why?
A
- ↑ risk of bleeding with antithrombotic therapy, Streptococcal infections, Allergic reactions, and Lacks fibrin specificity
- bleeding during surgery and cerebral hemorrhage
- > 75 years old –> increased risk of hemorrhagic stroke with other agents
31
Q
- What is the other drug name for Urokinase?
- What type of drug is this?
- This drug is an enzyme found in?
- This drug is bioengineered from?
- Causes direct conversion of?
- Adverse side effects and precautions are similar to?
A
- Abbokinase
- thrombolytic drugs
- human urine
- kidney cells cultures
- Plasminogen to plasmin
- Streptokinase
32
Q
- What is the other drug name for Alteplase? (2)
- What type of drug is this?
- MOA? (3)
A
- activase, rt-PA
- thrombolytic agent
- endothelial cells of vessel walls release rt-PA, splits plasminogen to release active plasmin, then dissolves fibrin mesh in clots
33
Q
- Alteplase (rt-PA) is only active for how long? Therefore, causes less?
- What does this drug degrade?
- Indicated for the acute treatment of? (2)
A
- 10 mins therefore, less bleeding than other thrombolytics
- circulating fibrinogen (can increase risk of hemorrhage)
- massive PE and acute ischemic stroke
34
Q
- What is the other drug name for Tenecteplase? (2)
- Recombinant version of?
- MOA?
A
- TNkase, TNK-tPA
- hamster cells
- tissue plasminogen activator –> splits plasminogen
35
Q
- Tenecteplase is commonly used to treat?
- This drug has high fibrin specificity causing?
- There is a moderate risk of what when taking this drug?
A
- STEMI
- low risk of systemic bleeding
- intracranial hemorrhage