B.44 Anticoagulant and Antiplatelet TX Flashcards

Question 1

Q

B.44 Anticoagulant and Antiplatelet TX

Unfractionated Heparin (UFH)

Answer

A

anti-coagulant

Question 2

Q

B.44 Anticoagulant and Antiplatelet TX

List all the anti-coagulants

Answer

A

Warfarin - A vitamin K antagonist that requires regular monitoring of INR levels and is used for various thromboembolic disorders.
Direct Oral Anticoagulants (DOACs):

Dabigatran - Direct thrombin inhibitor.
Rivaroxaban - Factor Xa inhibitor.
Apixaban - Factor Xa inhibitor.
Edoxaban - Factor Xa inhibitor.

Heaprin

Question 3

Q

B.44 Anticoagulant and Antiplatelet TX

List all the Anti-platelets

Answer

A

Aspirin - Inhibits cyclooxygenase (COX-1) and decreases thromboxane A2 production.
Clopidogrel - A thienopyridine that irreversibly blocks the P2Y12 ADP receptor.
Prasugrel - A thienopyridine that irreversibly inhibits the P2Y12 ADP receptor, more potent than clopidogrel.
Ticagrelor - A reversible inhibitor of the P2Y12 ADP receptor.
Dipyridamole - An antiplatelet drug that inhibits the uptake of adenosine and increases platelet cyclic AMP levels.
Gp IIb/IIIa antagonists - These include:

Abciximab

Question 4

Q

B.44 Anticoagulant and Antiplatelet TX

Unfractionated Heparin (UFH) MOA

Answer

A

Unfractionated heparin acts by binding to antithrombin III, which inhibits thrombin and factor Xa, leading to anticoagulation.

Question 5

Q

B.44 Anticoagulant and Antiplatelet TX

How is unfractionated heparin administered?

Answer

A

A: Unfractionated heparin is administered parenterally, either through subcutaneous (SC) injection or continuous intravenous (IV) infusion.

Question 6

Q

B.44 Anticoagulant and Antiplatelet TX

What is a major clinical use of unfractionated heparin?

Answer

A

A: Unfractionated heparin is used for the prevention and treatment of venous thromboembolism (VTE) and in acute coronary syndrome (ACS).

Question 7

Q

B.44 Anticoagulant and Antiplatelet TX

UFH clinical use

Answer

A

immediate anticoagulation for PE, ACS, MI, DVT

can be used during pregnacy, does not cross placenta

Question 8

Q

B.44 Anticoagulant and Antiplatelet TX

how to monitor UFH

Question 9

Q

B.44 Anticoagulant and Antiplatelet TX

SE UFH

Answer

A

Bleeding
Thrombocytopenia (HIT)
Osteoporosis
drug-drug interaction

Question 10

Q

B.44 Anticoagulant and Antiplatelet TX

Antidote UFH

Answer

A

protamine sulfate

Question 11

Q

B.44 Anticoagulant and Antiplatelet TX

What is the range of plasma half-life for unfractionated heparin?

Answer

A

A: The plasma half-life of unfractionated heparin typically ranges from 30 to 60 minutes, depending on the dose and clearance mechanisms.

Question 12

Q

B.44 Anticoagulant and Antiplatelet TX

What monitoring is required for patients on unfractionated heparin?

Answer

A

A: Patients on unfractionated heparin require monitoring of activated partial thromboplastin time (aPTT) to ensure appropriate anticoagulation levels.

Question 13

Q

B.44 Anticoagulant and Antiplatelet TX

What is one of the key disadvantages of using unfractionated heparin?

Answer

A

A: The anticoagulant response to unfractionated heparin can be unpredictable due to variable patient responses and binding to plasma proteins.

Question 14

Q

B.44 Anticoagulant and Antiplatelet TX

Why is unfractionated heparin often replaced by low-molecular-weight heparins (LMWH)?

Answer

A

A: LMWH has more predictable pharmacokinetics, longer half-life, lower risk of heparin-induced thrombocytopenia, and does not require routine monitoring.

Question 15

Q

B.44 Anticoagulant and Antiplatelet TX

In what situation is the use of unfractionated heparin preferred over LMWH?

Answer

A

A: Unfractionated heparin is preferred in patients requiring rapid reversal of anticoagulation, such as in cases of major bleeding or urgent surgical procedures.

Question 16

Q

B.44 Anticoagulant and Antiplatelet TX

What is one of the significant complications of long-term unfractionated heparin use?

Answer

A

A: Long-term use of unfractionated heparin can lead to osteoporosis and vertebral fractures due to decreased bone density.

Question 17

Q

B.44 Anticoagulant and Antiplatelet TX

Low molecular weight heparin/Enoxaprin

Answer

A

Anti-coagulant

Question 18

Q

B.44 Anticoagulant and Antiplatelet TX

MOA LMWH

Answer

A

predominately acts on factor Xa

Question 19

Q

B.44 Anticoagulant and Antiplatelet TX

Clinical Use LMWH/Enoxaparin

Answer

A

immediate anticoagulation for PE, ACS, MI, DVT

Question 20

Q

B.44 Anticoagulant and Antiplatelet TX

LMWH/Enoxaparin administration

Answer

A

Subcutaneously, does not need lab monitoring

Question 21

Q

B.44 Anticoagulant and Antiplatelet TX

LMWH/Enoxaparin bioavaliability

Answer

A

better than UFH 2-4x longer half life

Question 22

Q

B.44 Anticoagulant and Antiplatelet TX

LMWH/Enoxaparin CI

Answer

A

renal insufficiency

Question 23

Q

B.44 Anticoagulant and Antiplatelet TX

LMWH/Enoxaparin antidote

Answer

A

partially inhibited by protamine sulfate . but not easily done

Question 24

Q

B.44 Anticoagulant and Antiplatelet TX

What is the mechanism of action for enoxaparin (LMWH)?

Answer

A

A: Enoxaparin potentiates the inhibitory effect of antithrombin on factor Xa more than on thrombin, leading to anticoagulation.

Question 25

Q

B.44 Anticoagulant and Antiplatelet TX

How is enoxaparin administered?

Answer

A

A: Enoxaparin is administered subcutaneously (SC) for prophylaxis and treatment of venous thromboembolism and can also be given intravenously if rapid effect is required.

Question 26

Q

B.44 Anticoagulant and Antiplatelet TX

What are the pharmacokinetic advantages of enoxaparin compared to unfractionated heparin?

Answer

A

A: Enoxaparin has more predictable pharmacokinetics, longer half-life, and higher bioavailability (~90%) after subcutaneous injection, making it easier to use without routine monitoring.

Question 27

Q

B.44 Anticoagulant and Antiplatelet TX

What is the typical dosing regimen for enoxaparin in the treatment of venous thromboembolism?

Answer

A

A: The usual dosing is 1 mg/kg every 12 hours or 1.5 mg/kg once daily, depending on the clinical situation and patient’s weight.

Question 28

Q

B.44 Anticoagulant and Antiplatelet TX

What is one of the major benefits of using LMWH like enoxaparin over unfractionated heparin?

Answer

A

A: Enoxaparin has a lower risk of inducing heparin-induced thrombocytopenia (HIT) and fewer drug-related complications, making it safer for long-term use.

Question 29

Q

B.44 Anticoagulant and Antiplatelet TX

Which patients may require caution or dosage adjustments when using enoxaparin?

Answer

A

A: Patients with renal impairment may require dosage adjustments, as LMWH is primarily cleared by the kidneys.

Question 30

Q

B.44 Anticoagulant and Antiplatelet TX

What are common indications for enoxaparin use?

Answer

A

A: Indications include prevention of deep vein thrombosis (DVT) in surgical or hospitalized patients, treatment of DVT and pulmonary embolism (PE), and management of acute coronary syndromes.

Question 31

Q

B.44 Anticoagulant and Antiplatelet TX

What is the risk of bleeding with enoxaparin compared to unfractionated heparin?

Answer

A

A: While bleeding risk exists with both, enoxaparin’s predictable response and lower incidence of thrombocytopenia make it associated with a relatively lower risk of bleeding complications.

Question 32

Q

B.44 Anticoagulant and Antiplatelet TX

What should patients be monitored for while on enoxaparin therapy?

Answer

A

A: Although routine monitoring is not necessary, patients should be monitored for signs of bleeding, renal function, and possibly anti-factor Xa levels in high-risk situations.

Question 33

Q

B.44 Anticoagulant and Antiplatelet TX

How does the efficacy of enoxaparin compare to that of unfractionated heparin?

Answer

A

A: Enoxaparin has been shown to be as effective as unfractionated heparin for the treatment and prevention of thromboembolic events, with the added benefits of convenience and safety.

Question 34

Q

B.44 Anticoagulant and Antiplatelet TX

What is Fondaparinux

Answer

A

It is a anti-coagulant, synthetic heparin

Question 35

Q

B.44 Anticoagulant and Antiplatelet TX

Fondaparinux MOA

Answer

A

Acts on on Factor Xa

Question 36

Q

B.44 Anticoagulant and Antiplatelet TX

What is fondaparinux?

Answer

A

A: Fondaparinux is a synthetic anticoagulant that is a selective inhibitor of factor Xa and a synthetic analogue of the antithrombin-binding pentasaccharide sequenc

Question 37

Q

B.44 Anticoagulant and Antiplatelet TX

How is fondaparinux administered?

Answer

A

A: Fondaparinux is administered subcutaneously (SC), typically once daily.

Question 38

Q

B.44 Anticoagulant and Antiplatelet TX

What is the mechanism of action of fondaparinux?

Answer

A

A: Fondaparinux binds to antithrombin, leading to the inhibition of factor Xa, but does not significantly inhibit thrombin.

Question 39

Q

B.44 Anticoagulant and Antiplatelet TX

What are the primary indications for fondaparinux use?

Answer

A

A: Fondaparinux is used for thromboprophylaxis in patients undergoing surgery, and for the treatment of acute deep vein thrombosis (DVT) and pulmonary embolism (PE).

Question 40

Q

B.44 Anticoagulant and Antiplatelet TX

What is the bioavailability of fondaparinux?

Answer

A

A: Fondaparinux has a bioavailability of approximately 100% after subcutaneous injection.

Question 41

Q

B.44 Anticoagulant and Antiplatelet TX

How is fondaparinux cleared from the body?

Answer

A

A: Fondaparinux is cleared primarily via the kidneys in an unchanged form, making renal function an important consideration in dosing.

Question 42

Q

B.44 Anticoagulant and Antiplatelet TX

What is the typical dosing for fondaparinux in the treatment of DVT or PE?

Answer

A

A: The initial dose is typically 7.5 mg once daily, with adjustments made for body weight: 5 mg for patients weighing <50 kg and 10 mg for those >100 kg.

Question 43

Q

B.44 Anticoagulant and Antiplatelet TX

What are the major side effects of fondaparinux?

Answer

A

A: The primary side effect of fondaparinux is bleeding. It does not cause heparin-induced thrombocytopenia (HIT) because it does not bind to PF4.

Question 44

Q

B.44 Anticoagulant and Antiplatelet TX

Why is fondaparinux considered beneficial for patients with a history of HIT?

Answer

A

A: Fondaparinux does not cross-react with HIT antibodies, making it a safer alternative for anticoagulation in patients who have developed HIT.

Question 45

Q

B.44 Anticoagulant and Antiplatelet TX

What significant limitation is associated with fondaparinux regarding reversal of anticoagulation?

Answer

A

A: Fondaparinux has no specific antidote, and protamine sulfate does not reverse its anticoagulant effects, complicating management in case of major bleeding.

Question 46

Q

B.44 Anticoagulant and Antiplatelet TX

What is Dabigatran

Answer

A

Anti-coagulant

Question 47

Q

B.44 Anticoagulant and Antiplatelet TX

MOA Dabigatran

Answer

A

Direct thrombin (IIa) inhibitor

Question 48

Q

B.44 Anticoagulant and Antiplatelet TX

Administration Dabigatran

Question 49

Q

B.44 Anticoagulant and Antiplatelet TX

Dabigatran antidote

Answer

A

Idarucizumab

Question 50

Q

B.44 Anticoagulant and Antiplatelet TX

What is dabigatran?

Answer

A

A: Dabigatran is a direct oral anticoagulant (DOAC) that inhibits thrombin, thereby preventing the formation of blood clots.

Question 51

Q

B.44 Anticoagulant and Antiplatelet TX

How does dabigatran work?

Answer

A

A: Dabigatran directly binds to the active site of thrombin, inhibiting its ability to convert fibrinogen to fibrin, which is essential for clot formation.

Question 52

Q

B.44 Anticoagulant and Antiplatelet TX

What are the primary indications for dabigatran use?

Answer

A

A: Dabigatran is used for stroke prevention in patients with nonvalvular atrial fibrillation and for the treatment and prevention of venous thromboembolism (VTE).

Question 53

Q

B.44 Anticoagulant and Antiplatelet TX

What is the bioavailability of dabigatran?

Answer

A

A: Dabigatran has a low bioavailability of approximately 6% due to extensive first-pass metabolism; it is often given with food to enhance absorption.

Question 54

Q

B.44 Anticoagulant and Antiplatelet TX

What are the typical dosing regimens for dabigatran when used for stroke prevention?

Answer

A

A: The usual dose for stroke prevention in nonvalvular atrial fibrillation is 150 mg taken twice daily, with a reduced dose of 75 mg twice daily for patients with moderate renal impairment.

Question 55

Q

B.44 Anticoagulant and Antiplatelet TX

What are the major side effects of dabigatran?

Answer

A

A: The most common side effect of dabigatran is bleeding, particularly gastrointestinal bleeding. Dyspepsia is also reported in about 10% of patients.

Question 56

Q

B.44 Anticoagulant and Antiplatelet TX

How is dabigatran cleared from the body?

Answer

A

A: Dabigatran is primarily cleared by the kidneys; therefore, caution is advised in patients with renal impairment, and dosage adjustments may be necessary.

Question 57

Q

B.44 Anticoagulant and Antiplatelet TX

What is the reversal agent for dabigatran?

Answer

A

A: Idarucizumab is the specific reversal agent for dabigatran, and it binds dabigatran with high affinity to neutralize its anticoagulant effect.

Question 58

Q

B.44 Anticoagulant and Antiplatelet TX

When should dabigatran be stopped prior to surgical procedures?

Answer

A

A: Dabigatran should be stopped 1-2 days before procedures associated with a moderate to high risk of bleeding; the timing depends on renal function.

Question 59

Q

B.44 Anticoagulant and Antiplatelet TX

What monitoring is recommended for patients on dabigatran therapy?

Answer

A

A: Routine coagulation monitoring is generally not required; however, assessment of renal function and monitoring for signs of bleeding are important.

Question 60

Q

B.44 Anticoagulant and Antiplatelet TX

What is argatroban?

Answer

A

A: Argatroban is a direct thrombin inhibitor used as an anticoagulant, specifically for patients with heparin-induced thrombocytopenia (HIT).

Question 61

Q

B.44 Anticoagulant and Antiplatelet TX

How does argatroban work?

Answer

A

A: Argatroban binds to the active site of thrombin, inhibiting its ability to convert fibrinogen to fibrin, thus preventing clot formation.

Question 62

Q

B.44 Anticoagulant and Antiplatelet TX

In which patient population is argatroban primarily used?

Answer

A

A: Argatroban is primarily used in patients with HIT, especially those who require anticoagulation and cannot use heparin.

Question 63

Q

B.44 Anticoagulant and Antiplatelet TX

What is the route of administration for argatroban?

Answer

A

A: Argatroban is administered via continuous intravenous (IV) infusion.

Question 64

Q

B.44 Anticoagulant and Antiplatelet TX

What is the half-life of argatroban?

Answer

A

A: The plasma half-life of argatroban is approximately 45 minutes.

Answer 63

A

A: The activated partial thromboplastin time (aPTT) is used to monitor argatroban’s anticoagulant effect, with the goal of achieving an aPTT that is 1.5 to 3 times the baseline value.

Answer 64

A

A: Argatroban prolongs INR, complicating the transition to warfarin; monitoring factor X levels can help in this transition instead of relying solely on INR.

Answer 65

A

A: The most common side effect of argatroban is bleeding. Other potential complications may include elevated liver enzymes.

Answer 66

A

A: No, argatroban is metabolized in the liver and is not cleared by the kidneys, making it safer for patients with renal impairment.

Answer 67

A

A: The typical starting dose of argatroban is 2 mcg/kg/min, which may be adjusted based on aPTT results and clinical responses.

Answer 68

A

A: Bivalirudin is a direct thrombin inhibitor that is used as an anticoagulant, especially in patients undergoing percutaneous coronary intervention (PCI).

Answer 69

A

A: Bivalirudin binds to the active site of thrombin and also interacts with exosite 1, inhibiting thrombin’s ability to convert fibrinogen to fibrin and thus preventing blood clot formation.

Answer 70

A

A: Bivalirudin is indicated for anticoagulation in patients undergoing PCI and for patients with heparin-induced thrombocytopenia (HIT).

Answer 71

A

A: Bivalirudin has a relatively short half-life of approximately 25 minutes.

Answer 72

A

A: Bivalirudin is administered via intravenous (IV) infusion, often starting with a bolus dose followed by a continuous infusion.

Answer 73

A

A: For PCI, bivalirudin is typically given as a bolus of 0.75 mg/kg followed by a continuous infusion of 1.75 mg/kg/hour.

Answer 74

A

A: The major side effect of bivalirudin is bleeding. Other side effects may include thrombocytopenia and elevated liver enzymes.

Answer 75

A

A: The activated clotting time (ACT) is commonly used to monitor the anticoagulant effect of bivalirudin, particularly during PCI procedures.

Answer 76

A

A: Yes, while bivalirudin is partially cleared via the kidneys, dosage adjustments may be necessary for patients with renal impairment.

Answer 77

A

A: Bivalirudin does not cause heparin-induced thrombocytopenia (HIT), making it a safer alternative for patients with this condition undergoing procedures.

Answer 78

A

A: Rivaroxaban is an oral anticoagulant that belongs to the class of direct Factor Xa inhibitors, used for preventing and treating thromboembolic disorders.

Answer 79

A

A: Rivaroxaban inhibits Factor Xa, which is crucial in the coagulation cascade, thereby preventing the conversion of prothrombin to thrombin and reducing clot formation.

Answer 80

A

A: Rivaroxaban is indicated for the prevention of stroke in non-valvular atrial fibrillation, treatment and prevention of venous thromboembolism (VTE), and for secondary prevention of cardiovascular events in patients with coronary artery disease.

Answer 81

A

A: The standard dose for non-valvular atrial fibrillation is 20 mg once daily, with a reduced dose of 15 mg for patients with a creatinine clearance of 15–49 mL/min.

Answer 82

A

A: Rivaroxaban is administered orally, with certain doses required to be taken with food to enhance absorption.

Answer 83

A

A: Common side effects include bleeding (e.g., gastrointestinal and intracranial bleeding) and, less commonly, liver enzyme elevations

Answer 84

A

A: The half-life of rivaroxaban ranges from 7 to 11 hours, which can vary based on renal function and other factors.

Answer 85

A

A: In patients with renal impairment, the dose of rivaroxaban may need to be adjusted, particularly for those with a creatinine clearance of less than 50 mL/min.

Answer 86

A

A: The reversal of rivaroxaban can be achieved using andexanet alfa, a recombinant variant of Factor Xa that sequesters the drug.

Answer 87

A

A: Rivaroxaban generally does not require routine monitoring, but assessments of adherence, bleeding risk, and renal function should be considered. Prothrombin time (PT) can provide qualitative information about its anticoagulant effect.

Answer 88

A

A: Apixaban is an oral anticoagulant that belongs to the class of direct Factor Xa inhibitors, used for preventing and treating thromboembolic disorders.

Answer 89

A

A: Apixaban inhibits Factor Xa, which plays a crucial role in the coagulation cascade, preventing the conversion of prothrombin to thrombin and thereby reducing thrombus formation.

Answer 90

A

A: Apixaban is indicated for the prevention of stroke in non-valvular atrial fibrillation, treatment and prevention of venous thromboembolism (VTE), and secondary prevention of thrombotic events in patients with coronary artery or peripheral artery disease.

Answer 91

A

A: The standard dose for non-valvular atrial fibrillation is 5 mg taken twice daily, with a reduced dose of 2.5 mg twice daily for patients meeting at least two of the “ABC” criteria (age >80 years, weight <60 kg, and serum creatinine >1.5 mg/dL).

Answer 92

A

A: Apixaban is taken orally, and it can be administered with or without food.

Answer 93

A

A: Common side effects include bleeding (such as gastrointestinal and intracranial bleeding) and, less commonly, elevated liver enzymes.

Answer 94

A

A: The half-life of apixaban is approximately 12 hours, which can vary based on individual factors, including renal function.

Answer 95

A

A: In patients with renal impairment, dosage reductions may be necessary for those with a creatinine clearance of 15–50 mL/min, especially for secondary prevention.

Answer 96

A

A: The reversal of apixaban can be achieved using andexanet alfa, which serves as a decoy to sequester oral Factor Xa inhibitors.

Answer 97

A

A: Routine coagulation monitoring is not required for patients on apixaban, but it may be helpful in specific situations such as assessing adherence, detecting accumulation or overdose, or evaluating bleeding mechanisms.

Answer 98

A

A: Warfarin is an oral anticoagulant medication that inhibits vitamin K-dependent clotting factors, used to prevent and treat thromboembolic disorders.

Answer 99

A

A: Warfarin works by inhibiting the vitamin K epoxide reductase complex, which is essential for the synthesis of clotting factors II, VII, IX, and X, and proteins C and S.

Answer 100

A

A: Warfarin is used for the prevention and treatment of venous thromboembolism (VTE), pulmonary embolism (PE), myocardial infarction, and for stroke prevention in patients with atrial fibrillation.

Answer 101

A

A: The anticoagulant effect of warfarin is delayed because it inhibits the synthesis of new clotting factors, which takes time, as existing factors in circulation must degrade before the effects become evident.

Answer 102

A

A: Warfarin dosing is individualized based on monitoring of the International Normalized Ratio (INR), with typical starting doses ranging from 2 to 5 mg daily, adjusted according to INR results.

Answer 103

A

A: Patients on warfarin require regular INR monitoring to ensure that the anticoagulation effect is within the therapeutic range, typically every 3 to 4 weeks for stable patients.

Answer 104

A

A: Common side effects include bleeding (both minor and major), purple toe syndrome, skin necrosis, and, less commonly, liver enzyme elevation.

Answer 105

A

A: At least half of the bleeding complications occur when the INR exceeds the therapeutic range; major bleeding events, such as gastrointestinal or intracranial bleeding, can occur as well.

Answer 106

A

A: Warfarin can be reversed with oral vitamin K for minor INR elevation or serious bleeding treated with intravenous vitamin K and prothrombin complex concentrates.

Answer 107

A

A: Warfarin is contraindicated in pregnancy due to the risk of fetal abnormalities and in patients with active bleeding or conditions that increase the risk of bleeding, such as thrombocytopenia.

Answer 108

A

A: Aspirin is a widely used antiplatelet medication and nonsteroidal anti-inflammatory drug (NSAID) that inhibits platelet aggregation and reduces inflammation.

Answer 109

A

A: Aspirin produces its antithrombotic effect by irreversibly acetylating cyclooxygenase-1 (COX-1), leading to the inhibition of thromboxane A2 (TXA2) synthesis, which is critical for platelet activation and aggregation.

Answer 110

A

A: Aspirin is used for secondary prevention of cardiovascular events in patients with established coronary artery, cerebral artery, or peripheral artery disease.

Answer 111

A

A: The usual dose of aspirin is between 75–325 mg once daily. Lower doses of 75–100 mg daily are often preferred due to a favorable balance of efficacy and safety.

Answer 112

A

A: The most common side effects of aspirin are gastrointestinal and include dyspepsia, erosive gastritis, and peptic ulcers, which can lead to bleeding.

Answer 113

A

A: Recent studies suggest that the potential gastrointestinal and intracerebral hemorrhage risks associated with aspirin may outweigh its benefits in primary prevention for cardiovascular events.

Answer 114

A

A: Aspirin resistance is the failure of aspirin to adequately prevent thrombotic events in some patients, which may be due to various factors such as poor compliance, drug interactions, or genetic variability.

Answer 115

A

A: Aspirin should not be administered to patients with a known history of aspirin allergy characterized by bronchospasm, especially those with asthma, chronic urticaria, or nasal polyps.

Answer 116

A

A: When aspirin is used with other antiplatelet drugs or anticoagulants, low-dose aspirin (75–100 mg daily) is recommended, and the risk of gastrointestinal bleeding may be reduced by administering proton pump inhibitors.

Answer 117

A

A: Aspirin should be used with caution during pregnancy, especially in the third trimester, due to the potential risks of bleeding; however, low-dose aspirin may be beneficial in certain high-risk patients under medical supervision.

Answer 118

A

A: Clopidogrel is an oral antiplatelet agent that inhibits platelet aggregation by irreversibly blocking the P2Y12 ADP receptor on platelets.

Answer 119

A

A: Clopidogrel is a prodrug that requires metabolic activation by the hepatic cytochrome P450 enzyme system to produce its active form, which then blocks the P2Y12 receptor, preventing ADP-induced platelet activation.

Answer 120

A

A: Clopidogrel is indicated for the prevention of cardiovascular events in patients with recent myocardial infarction, recent ischemic stroke, or a history of peripheral artery disease. It is also used in combination with aspirin after coronary stenting.

Answer 121

A

A: The common initial dose of clopidogrel is 75 mg once daily; however, a loading dose of 300-600 mg may be given for rapid platelet inhibition, especially in urgent situations such as coronary intervention.

Answer 122

A

A: The most common side effects of clopidogrel include bleeding complications, such as minor bruising or major bleeding events. Other rare side effects include neutropenia and thrombotic thrombocytopenic purpura (TTP).

Answer 123

A

A: In some studies, clopidogrel has shown to be slightly less effective than aspirin alone for certain primary prevention scenarios, although it is more effective in the context of dual antiplatelet therapy, particularly after stenting.

Answer 124

A

A: Clopidogrel resistance refers to the variability in the drug’s effectiveness among individuals, often linked to genetic polymorphisms in the CYP2C19 enzyme that impair its metabolic activation.

Answer 125

A

A: Yes, clopidogrel is often used in conjunction with aspirin to enhance antiplatelet effects, particularly in patients with acute coronary syndromes or after stent placement, but this combination increases the risk of bleeding.

Answer 126

A

A: Caution should be exercised in patients with a high risk of bleeding, and clopidogrel may need to be stopped 5-7 days prior to major surgery to minimize bleeding risks.

Answer 127

A

A: Alternatives to clopidogrel include other P2Y12 inhibitors such as prasugrel and ticagrelor, which may be more effective in certain populations but come with different efficacy and safety profiles.

Answer 128

A

A: Prasugrel is an oral antiplatelet medication that inhibits platelet aggregation by irreversibly blocking the P2Y12 ADP receptor.

Answer 129

A

A: Unlike clopidogrel, prasugrel is more potent and has a more rapid onset of action because it has a more straightforward metabolic activation pathway and does not rely heavily on the CYP450 enzyme system.

Answer 130

A

A: Prasugrel is indicated for the prevention of thrombotic cardiovascular events in patients with acute coronary syndromes undergoing percutaneous coronary intervention (PCI).

Answer 131

A

A: After an initial loading dose of 60 mg, prasugrel is given at a daily maintenance dose of 10 mg; however, patients over 75 years old or weighing less than 60 kg should receive 5 mg daily.

Answer 132

A

A: The most common side effects include bleeding complications, such as major or life-threatening bleeding, and other rare hematologic effects like thrombocytopenia.

Answer 133

A

A: Prasugrel is contraindicated in patients with a history of prior stroke or transient ischemic attack due to an increased risk of bleeding.

Answer 134

A

A: In clinical trials, prasugrel was associated with a lower incidence of cardiovascular death, myocardial infarction (MI), and stent thrombosis compared to clopidogrel, though it also led to higher rates of bleeding.

Answer 135

A

A: Prasugrel should typically be discontinued 5-7 days prior to major surgical procedures to reduce the risk of bleeding.

Answer 136

A

A: Elderly patients (over 75 years old) are at a higher risk of bleeding; thus, a lower maintenance dose of 5 mg is recommended for safety.

Answer 137

A

A: Prasugrel is often used in combination with aspirin to enhance antiplatelet effects after coronary interventions, particularly PCI.

Answer 138

A

A: Abciximab is a glycoprotein IIb/IIIa antagonist used as an antiplatelet agent to prevent platelet aggregation during and after percutaneous coronary intervention (PCI).

Answer 139

A

A: Abciximab inhibits the binding of fibrinogen and von Willebrand factor to glycoprotein IIb/IIIa receptors on activated platelets, thereby preventing platelet aggregation.

Answer 140

A

A: Abciximab is indicated for use in patients undergoing PCI and is especially beneficial for those who have not been pretreated with other antiplatelet agents like aspirin or clopidogrel.

Answer 141

A

A: Abciximab is given as an intravenous bolus (0.25 mg/kg) followed by an infusion (0.125 µg/kg/min) for up to 12 hours.

Answer 142

A

A: Common side effects include bleeding complications and thrombocytopenia, which is immune-mediated and can be severe in some patients.

Answer 143

A

A: Abciximab is a Fab fragment of a humanized monoclonal antibody, giving it a long plasma half-life and a prolonged effect on platelet aggregation inhibition.

Answer 144

A

A: Platelet counts should be monitored, especially if thrombocytopenia is suspected, as this condition can occur approximately in 5% of patients treated with abciximab.

Answer 145

A

A: If serious bleeding occurs, abciximab should be discontinued immediately, and supportive measures should be taken, including potential platelet transfusions.

Answer 146

A

A: Abciximab is particularly beneficial in high-risk patients undergoing PCI who may require intensive antiplatelet therapy to decrease the risk of events like stent thrombosis.

Answer 147

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A: Yes, abciximab is contraindicated in patients with active bleeding, severe hypertension, and in those with a history of stroke within the last 30 days.

Answer 148

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A: Dipyridamole is an antiplatelet agent that inhibits platelet aggregation, often used in combination with aspirin for secondary prevention of thromboembolic events.

Answer 149

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A: Dipyridamole works by inhibiting phosphodiesterase, leading to increased levels of cyclic adenosine monophosphate (cAMP) in platelets, which inhibits platelet activation and aggregation.

Answer 150

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A: Dipyridamole is available in an oral form, and it is often used in an extended-release formulation combined with low-dose aspirin, known as Aggrenox.

Answer 151

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A: Dipyridamole is indicated for the secondary prevention of stroke in patients with a history of transient ischemic attacks (TIAs) or ischemic stroke when used in combination with aspirin.

Answer 152

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A: Studies have shown that dipyridamole combined with aspirin can reduce the risk of recurrent stroke compared to aspirin alone.

Answer 153

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A: Common side effects include headaches, gastrointestinal complaints, dizziness, facial flushing, and hypotension due to its vasodilatory effects.

Answer 154

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A: Dipyridamole should be used cautiously in patients with coronary artery disease due to its potential vasodilatory effects.

Answer 155

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A: Due to limited data supporting its effectiveness in this population and the risk of vasodilatory side effects, alternative antiplatelet therapies, such as clopidogrel, are preferred.

Answer 156

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A: Dipyridamole is generally not effective as a monotherapy for antiplatelet treatment; it is most effective when used in combination with aspirin.

Answer 157

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A: Cilostazol is an antiplatelet medication primarily used to treat intermittent claudication in patients with peripheral artery disease (PAD).

Answer 158

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A: Cilostazol inhibits phosphodiesterase type 3 (PDE3), leading to increased levels of cyclic adenosine monophosphate (cAMP) in platelets, which reduces platelet aggregation and promotes vasodilation.

Answer 159

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A: Cilostazol is indicated for the management of intermittent claudication, improving walking distance and quality of life in patients with PAD.

Answer 160

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A: The typical dosing regimen for cilostazol is 100 mg taken twice daily.

Answer 161

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A: Common side effects include headache, diarrhea, dizziness, palpitations, and peripheral edema.

Answer 162

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A: Yes, cilostazol is contraindicated in patients with heart failure of any severity due to potential worsening of the condition.

Answer 163

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A: Cilostazol is specifically effective for improving exercise tolerance in patients with PAD, but it may not be as widely used for other indications like myocardial infarction prevention.

Answer 164

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A: Yes, cilostazol can be used with other agents like aspirin, but careful monitoring is necessary to avoid increased bleeding risk.

Answer 165

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A: Cilostazol may take several weeks to show significant improvement in symptoms, thus patience and adherence to the treatment regimen are essential.

Answer 166

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A: Patients should be advised to engage in a supervised exercise program and make lifestyle changes such as smoking cessation to maximize the benefits of cilostazol.

Answer 167

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A: Ticagrelor is an oral antiplatelet medication used to reduce the risk of thrombotic cardiovascular events in patients with acute coronary syndrome or those undergoing percutaneous coronary intervention.

Answer 168

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A: Ticagrelor selectively inhibits the P2Y12 ADP receptor on platelets, leading to reversible inhibition of platelet activation and aggregation, which helps prevent clot formation.

Answer 169

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A: Ticagrelor has a more rapid onset of action than clopidogrel, as it does not require metabolic activation.

Answer 170

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A: The usual dosing regimen for ticagrelor is an initial loading dose of 180 mg, followed by 90 mg twice daily.

Answer 171

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A: Ticagrelor is indicated for the secondary prevention of atherothrombotic events in patients with acute coronary syndrome and can also be used following percutaneous coronary intervention.

Answer 172

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A: Common side effects include bleeding, dyspnea (shortness of breath), and asymptomatic ventricular pauses.

Answer 173

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A: Ticagrelor is primarily metabolized in the liver via the CYP3A4 enzyme, which can be affected by other medications that inhibit or induce this enzyme.

Answer 174

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A: Ticagrelor should be discontinued at least 5 days prior to major surgery to reduce the risk of bleeding.

Answer 175

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A: Unlike clopidogrel, ticagrelor provides greater and more predictable inhibition of platelet aggregation, making it a preferred option in higher-risk patients.

Answer 176

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A: While platelet transfusions may not be effective due to ticagrelor’s mechanism, a reversal agent called bentracimab is under development to rapidly reverse ticagrelor’s effects in emergency situations.

Answer 177

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What is dual antiplatelet therapy (DAPT)?
A: DAPT is the use of two antiplatelet medications concurrently to reduce the risk of thrombotic events, typically combining aspirin with a second antiplatelet agent, such as clopidogrel or ticagrelor.

Answer 178

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A: DAPT is used to prevent cardiovascular events, particularly after procedures like coronary stenting or in patients with acute coronary syndrome (ACS).

Answer 179

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A: DAPT is used to prevent cardiovascular events, particularly after procedures like coronary stenting or in patients with acute coronary syndrome (ACS).

Answer 180

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A: Indications include post-percutaneous coronary intervention (PCI), acute myocardial infarction (AMI), and non-ST elevation myocardial infarction (NSTEMI).

Answer 181

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A: Aspirin irreversibly inhibits cyclooxygenase-1 (COX-1), leading to decreased thromboxane A2 production, which reduces platelet activation and aggregation.

Answer 182

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A: Clopidogrel irreversibly inhibits the P2Y12 ADP receptor on platelets, preventing their activation and aggregation in response to adenosine diphosphate (ADP).

Answer 183

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A: DAPT is usually recommended for at least 6-12 months after drug-eluting stent placement, while bare metal stents typically require at least 1 month of DAPT.

Answer 184

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A: The main risk is increased bleeding, including gastrointestinal bleeding and intracranial hemorrhage, particularly in older adults or those with a history of bleeding disorders.

Answer 185

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A: Ticagrelor is a reversible inhibitor of the P2Y12 receptor, has a faster onset of action, and does not require metabolic activation, making it more effective in some patients.

Answer 186

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A: Factors include the type of stent used, the patient’s risk of thrombotic versus bleeding events, and clinical guidelines based on the patient’s overall health and history of cardiovascular disease.