Podcast
Questions and Answers
What is the primary effect of antiplatelet medications on blood coagulation?
What is the primary effect of antiplatelet medications on blood coagulation?
- Stimulation of fibrinolysis
- Enhancement of coagulation factor synthesis
- Inhibition of platelet activation (correct)
- Inhibition of clotting factors
What are the two main ADP receptors on the platelet membrane involved in platelet aggregation?
What are the two main ADP receptors on the platelet membrane involved in platelet aggregation?
- P2Y5 and P2Y8
- P2Y12 and P2Y1 (correct)
- P2Y3 and P2Y9
- P2Y10 and P2Y15
What is the most significant adverse effect associated with antiplatelet and anticoagulant medications?
What is the most significant adverse effect associated with antiplatelet and anticoagulant medications?
- Nephrotoxicity
- Hypertension
- Tachycardia
- Bleeding (correct)
What is the main therapeutic use of antiplatelet medications?
What is the main therapeutic use of antiplatelet medications?
What is the primary mechanism of platelet activation in response to vascular injury?
What is the primary mechanism of platelet activation in response to vascular injury?
What is the precaution that should be taken when considering antiplatelet or anticoagulant therapy in patients with certain medical conditions?
What is the precaution that should be taken when considering antiplatelet or anticoagulant therapy in patients with certain medical conditions?
What is the outcome of TXA2 activation on the platelet membrane?
What is the outcome of TXA2 activation on the platelet membrane?
Which antiplatelet medication inhibits the enzyme responsible for breakdown of cAMP in platelet?
Which antiplatelet medication inhibits the enzyme responsible for breakdown of cAMP in platelet?
What is the outcome of thrombin activation on platelets?
What is the outcome of thrombin activation on platelets?
What is the mechanism of action of aspirin as an antiplatelet medication?
What is the mechanism of action of aspirin as an antiplatelet medication?
What is the indication for aspirin use in acute coronary syndrome?
What is the indication for aspirin use in acute coronary syndrome?
Which of the following is a PAR-1 receptor inhibitor?
Which of the following is a PAR-1 receptor inhibitor?
What is the indication of clopidogrel in acute coronary syndrome?
What is the indication of clopidogrel in acute coronary syndrome?
What is the mechanism of clopidogrel's therapeutic effect?
What is the mechanism of clopidogrel's therapeutic effect?
What is the potential effect of smoking on clopidogrel's therapeutic effect?
What is the potential effect of smoking on clopidogrel's therapeutic effect?
What is the potential interaction between clopidogrel and proton pump inhibitors (PPIs)?
What is the potential interaction between clopidogrel and proton pump inhibitors (PPIs)?
What is the reason for the variable response to clopidogrel in some patients?
What is the reason for the variable response to clopidogrel in some patients?
What is the boxed warning related to clopidogrel?
What is the boxed warning related to clopidogrel?
What is the indication of prasugrel in patients with acute coronary syndrome?
What is the indication of prasugrel in patients with acute coronary syndrome?
Which of the following is a boxed warning for prasugrel?
Which of the following is a boxed warning for prasugrel?
What is the difference between ticagrelor and clopidogrel in terms of conversion to active metabolite?
What is the difference between ticagrelor and clopidogrel in terms of conversion to active metabolite?
Which of the following is a contraindication for prasugrel?
Which of the following is a contraindication for prasugrel?
What is the mechanism of action of ticagrelor?
What is the mechanism of action of ticagrelor?
Which of the following is a notable, rare adverse effect of prasugrel and ticagrelor?
Which of the following is a notable, rare adverse effect of prasugrel and ticagrelor?
What is the recommended loading dose of aspirin for acute coronary syndrome?
What is the recommended loading dose of aspirin for acute coronary syndrome?
Which P2Y12 inhibitor is preferred for acute coronary syndrome patients who require PCI?
Which P2Y12 inhibitor is preferred for acute coronary syndrome patients who require PCI?
What is the primary benefit of dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome?
What is the primary benefit of dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome?
In which patients is antiplatelet therapy contraindicated?
In which patients is antiplatelet therapy contraindicated?
What is the typical duration of dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome?
What is the typical duration of dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome?
Which trial supported the preference for ticagrelor over clopidogrel in non-invasive treatment of acute coronary syndrome?
Which trial supported the preference for ticagrelor over clopidogrel in non-invasive treatment of acute coronary syndrome?
What is the result of TXA2 activation on the platelet membrane?
What is the result of TXA2 activation on the platelet membrane?
Which of the following antiplatelet medications acts by inhibiting the breakdown of cAMP in platelets?
Which of the following antiplatelet medications acts by inhibiting the breakdown of cAMP in platelets?
What is the common pathway of platelet activation in response to vascular injury?
What is the common pathway of platelet activation in response to vascular injury?
What is the primary effect of antiplatelet medications on blood coagulation?
What is the primary effect of antiplatelet medications on blood coagulation?
Which of the following antiplatelet medications is an ATP analogue?
Which of the following antiplatelet medications is an ATP analogue?
What is the duration of the antiplatelet effect of aspirin?
What is the duration of the antiplatelet effect of aspirin?
What is the recommended dose range for aspirin as an antiplatelet medication?
What is the recommended dose range for aspirin as an antiplatelet medication?
Which of the following is a contraindication for aspirin use in patients undergoing total hip or total knee arthroplasty?
Which of the following is a contraindication for aspirin use in patients undergoing total hip or total knee arthroplasty?
What is the effect of omeprazole on clopidogrel's therapeutic effect?
What is the effect of omeprazole on clopidogrel's therapeutic effect?
What is the benefit of spacing out daily aspirin from other non-selective NSAIDs in patients undergoing total hip or total knee arthroplasty?
What is the benefit of spacing out daily aspirin from other non-selective NSAIDs in patients undergoing total hip or total knee arthroplasty?
Which of the following medications is used for secondary prevention of ischemic stroke or TIA?
Which of the following medications is used for secondary prevention of ischemic stroke or TIA?
What is the effect of smoking on CYP enzymes involved in clopidogrel's conversion to its active metabolite?
What is the effect of smoking on CYP enzymes involved in clopidogrel's conversion to its active metabolite?
What is the primary effect of antiplatelet medications on platelet activation?
What is the primary effect of antiplatelet medications on platelet activation?
What is the role of Von Willebrand factor in platelet activation?
What is the role of Von Willebrand factor in platelet activation?
Which of the following medications is NOT an antiplatelet drug?
Which of the following medications is NOT an antiplatelet drug?
What is the result of platelet activation in response to vascular injury?
What is the result of platelet activation in response to vascular injury?
Which of the following is NOT a mechanism of platelet activation?
Which of the following is NOT a mechanism of platelet activation?
What is the primary therapeutic use of antiplatelet medications?
What is the primary therapeutic use of antiplatelet medications?
What is the mechanism of action of ticagrelor in platelet inhibition?
What is the mechanism of action of ticagrelor in platelet inhibition?
Which of the following P2Y12 receptor inhibitors has a boxed warning for bleeding risk?
Which of the following P2Y12 receptor inhibitors has a boxed warning for bleeding risk?
What is the primary indication for dipyridamole?
What is the primary indication for dipyridamole?
What is the mechanism of action of cilostazol in platelet inhibition?
What is the mechanism of action of cilostazol in platelet inhibition?
Which of the following antiplatelet medications is contraindicated in heart failure of any severity?
Which of the following antiplatelet medications is contraindicated in heart failure of any severity?
What is the main therapeutic benefit of vorapaxar?
What is the main therapeutic benefit of vorapaxar?
What is the primary route of excretion for eptifibatide?
What is the primary route of excretion for eptifibatide?
Which of the following antiplatelet medications has a long receptor dissociation time?
Which of the following antiplatelet medications has a long receptor dissociation time?
What is the primary side effect of dipyridamole?
What is the primary side effect of dipyridamole?
Which of the following antiplatelet medications is not routinely used?
Which of the following antiplatelet medications is not routinely used?
What is the primary benefit of dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome?
What is the primary benefit of dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome?
In which patients should antiplatelet medications be avoided?
In which patients should antiplatelet medications be avoided?
What is the typical duration of dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome?
What is the typical duration of dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome?
What is the primary complication of dual antiplatelet therapy (DAPT)?
What is the primary complication of dual antiplatelet therapy (DAPT)?
What is the loading dose of aspirin recommended for acute coronary syndrome?
What is the loading dose of aspirin recommended for acute coronary syndrome?
Which P2Y12 inhibitor is preferred for acute coronary syndrome patients who require PCI?
Which P2Y12 inhibitor is preferred for acute coronary syndrome patients who require PCI?
Study Notes
Antiplatelet Drugs
- Antiplatelet drugs are divided into five classes: cyclooxygenase inhibitors, phosphodiesterase inhibitors, GPIIb/IIIa inhibitors, P2Y12 receptor inhibitors, and PAR-1 receptor inhibitors
- Antiplatelet drugs are used to prevent platelet aggregation and reduce the risk of cardiovascular events
Cyclooxygenase Inhibitors
- Aspirin is an example of a cyclooxygenase inhibitor
- Aspirin works by irreversibly inhibiting COX-1, which inhibits the synthesis of TXA2
- Aspirin's antiplatelet effect lasts for 24-36 hours, until new platelets are generated
- Aspirin has adverse effects such as GI upset, tinnitus, hypersensitivity reaction, and bleeding (GI mostly, but also rarely ICH)
P2Y12 Receptor Inhibitors
- Examples of P2Y12 receptor inhibitors include clopidogrel, ticagrelor, and prasugrel
- These drugs work by blocking the P2Y12 receptor on the platelet surface, which prevents activation of the GPIIb/IIIa receptor complex and reduces platelet aggregation
- Indications for P2Y12 receptor inhibitors include acute coronary syndrome, secondary prevention of atherosclerotic cardiovascular disease, and peripheral arterial disease
Phosphodiesterase Inhibitors
- Examples of phosphodiesterase inhibitors include dipyridamole and cilostazol
- These drugs work by inhibiting the enzyme responsible for breaking down cAMP in platelets, which increases cAMP and reduces platelet aggregation
GPIIb/IIIa Inhibitors
- Examples of GPIIb/IIIa inhibitors include eptifibatide and tirofiban
- These drugs work by blocking the GPIIb/IIIa receptors on the platelet surface, which prevents fibrinogen binding and reduces platelet aggregation
PAR-1 Receptor Inhibitors
- Vorapaxar is an example of a PAR-1 receptor inhibitor
- This drug works by blocking the PAR-1 receptor on platelets, which inhibits thrombin-induced and thrombin receptor agonist peptide (TRAP)-induced platelet aggregation### Ticagrelor
- Reversibly binds to an area distinct from the ADP binding site, allowing redistribution to new platelets as they are formed
- PLATO trial: reduced composite primary end point (death from vascular causes, MI, or stroke) compared to clopidogrel, with no difference in bleeding risk
- Boxed warning for bleeding risk, contraindicated in active bleeding or urgent CABG
- Concomitant aspirin dose must be ≤100mg
Ticagrelor Pharmacokinetics
- Onset of effect: 30 minutes
- Time to maximum effect: 2-3 hours
- Platelet function returns to baseline: 5 days
Thrombotic Thrombocytopenic Purpura (TTP)
- Thrombotic microangiopathy caused by small vessel platelet thrombi
- Leads to thrombocytopenia and hemolytic anemia
- Common drug causes: chemotherapeutic agents, immunosuppressive agents, drugs of abuse, and emicizumab
- Possible link to P2Y12 receptor antagonists (clopidogrel and ticlopidine)
GPIIb/IIIa Receptor Inhibitors
- Eptifibatide and tirofiban (abciximab)
- MOA: prevents cross-linking by interfering with fibrinogen binding to GPIIb/IIIa receptor
- Indications: acute coronary syndrome, primary PCI, alternative
- Renal dose adjustment required
- Adverse effects: bleeding
- Contraindications: active bleeding, history of stroke, severe HTN, major surgery, HD
Dipyridamole
- MOA: phosphodiesterase inhibitor, increases cAMP, inhibits platelet function and causes vasodilation
- Formulated as a capsule in combination with aspirin (Aggrenox)
- Indication: secondary prevention of ischemic stroke or TIA
- Off-label uses: hemodialysis graft patency, symptomatic carotid artery stenosis
- Adverse effects: headache, hypotension, GI side effects, tinnitus
Cilostazol
- MOA: phosphodiesterase III inhibitor, increases cAMP, inhibits platelet aggregation and causes vasodilation
- Indication: intermittent claudication in peripheral artery disease
- Boxed warning: contraindicated in heart failure of any severity
- Adverse effects: headache, diarrhea, dizziness, palpitations
- High fat meals increase absorption, take between meals
- Drug interactions with CYP inhibitors increase cilostazol level
Vorapaxar
- PAR-1 receptor antagonist
- Indication: History of MI or established Peripheral Arterial Disease
- PK: long t1/2 = about 8 days, long receptor dissociation time
- Inhibition of platelet aggregation lasts up to 4 weeks after discontinuation
- Boxed warning: Bleeding risk
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Description
Test your knowledge of antiplatelet drugs, including their mechanism of action, antiplatelet actions, administration and elimination, adverse effects, and drug interactions. This quiz covers the key concepts and details of each drug class.
