CVS Drugs Part 1 Flashcards
Antiplatelet/Antithrombotic Drugs & Anti-Arrhythmic Drugs
First step in platelet aggregation
damage to endothelium causes platelets to become activated which cover and adhere to exposed subendothelial surface -> platelet adhesion
Second step of platelet aggregation
activated platelets release chemical mediators including thromboxane A2, ADP, serotonin, and PAF -> platelet activation
Third step of platelet aggregation
platelets are recruited forming platelet plug -> platelet aggregation
Intrinsic pathway factors
activation of factors XII, XI, IX, and VIII leading to activation of factor X
Extrinsic pathway factors
activation of factors III (tissue factor) and VII leading to activation of factor X
Common pathway factors
activation of factor X through extrinsic and intrinsic pathways leading to conversion of prothrombin (factor II) to thrombin (factor IIa), activation of factor XIII, and conversion of fibrinogen (factor I) to fibrin (factor Ia) resulting in fibrin clot formation
fibrinolysis
break down of a fibrin clot by plasmin after conversion of plasminogen to plasmin
Aspirin MOA
antiplatelet drug that irreversibly inhibits COX-1 enzyme inhibiting platelet aggregation (by inhibition of thromboxane A2 synthesis from prostaglandins)
Aspirin clinical indications
- primary and secondary prevention of heart attack and stroke in patients previously diagnosed with CAD, DM, PVD, CVA, and TIA
- in DAPT combined with P2Y12 ADP inhibitor (clopidogrel) recommended after CABG, PCI, stroke, and TIA (for 2 weeks)
Aspirin contraindications
intracranial, intramedullary, or posterior eye surgeries
Aspirin adverse effects
GI bleeding (especially in the elderly) and tinnitus
Clopidogrel MOA
antiplatelet drug that is an irreversible P2Y12 ADP receptor inhibitor causing inhibition of platelet activation
Clopidogrel clinical indications
1st line drug for prevention of atherosclerotic events in recent MI, CVA, unstable angina, ACS, and coronary angioplasty
- used in DAPT combined with aspirin for 1-6 months in BMS, 12 months in DES,12 months in ACS, and 10-21 days in TIA/minor ischemic strokes (not in major CVA d/t bleeding risk)
Clopidogrel contraindications
do not use during episodes of active bleeding, in patients with a history of bleeding, history of vascular disease including stable angina, prior TIA or stroke, and PAD
DAPT score associated with favorable benefit/risk ratio for prolonged DAPT
score of greater than or equal to 2
risk factors that increase DAPT score
tobacco smoking, diabetes, MI at presentation, prior PCI or MI, stent diameter <3 mm, paclitaxel-eluting stent, CHF or LVEF <30% (+2), and saphenous vein graft PCI (+2)
Clopidogrel pharmacokinetics
prodrug that is metabolized by CYP 2C19, onset = 2 hours (effects last 5 days)
clopidogrel drug interactions
omeprazole which inhibits CYP (if PPI needed, use pantoprazole)
Ticagrelor (Brilinta) MOA
only antiplatelet drug that is a reversible P2Y12 ADP receptor inhibitor
Ticagrelor pharmacokinetics
administered orally and is not metabolized by CYP (not a prodrug like clopidogrel), has fastest onset = 1-3 hours
Ticagrelor clinical indications
- 2nd line for prevention of atherosclerotic events in recent MI, CVA, unstable angina, ACS, and coronary angioplasty
- used in DAPT combined with aspirin
Prasugrel (Effient) MOA
antiplatelet drug that is an irreversible P2Y12 ADP receptor inhibitor with increased antiplatelet activity
Prasugrel clinical indications
used in combination with aspirin in ACS and after MI and stroke (not used routinely)
Prasugrel contraindications
increased risk of bleeding (especially >75 yo)