Antiplatelets Flashcards
name the antiplatelets
aspirin, clopidogrel, prasugrel, ticagrelor, vorapaxar, cilostazol, dipyridamole
what is the mechanism of aspirin
it inhibits COX1 through irreversible acetylation so arachidonic acid is not converted to prostaglandin
when would you consider aspirin for PRIMARY prevention
adults 40-59 w/ 10 yr ASCVD risk greater than 10%, if they are not at increased risk for bleeding
who should NOT be initiated on aspirin for PRIMARY prevention
adults over 60
what are the indications for aspirin
CAD, PAD, ACS, PCI, acute ischemic stroke, SECONDARY prevention
adverse effects of aspirin
bleeding, rash, GI events
what are the P2Y12 inhibitors
clopidogrel, prasugrel, ticagrelor
what are the thienopyridines
clopidogrel, prasugrel
what is the non-thienopyridine
ticagrelor
what is the brand name for clopidogrel
plavix
what is the brand name for prasugrel
effient
what is the brand name for ticagrelor
brilanta
the thienopyridines are _____ (reversible/irreversible)
irreversible
the non-thienopyridines are _____ (reversible/irreversible)
reversible
which P2Y12’s are prodrugs
clopidogrel and prasugrel
how is clopidogrel metabolized
CYP2C19, 2 steps
how is prasugrel metabolized
CYP2C19, 1 step
how is ticagrelor metabolized
CYP3A4
what is the mechanism of the thienopyridines
they inhibit P2Y12 from binding to ADP by an irreversible, delayed inhibition
what are the indications for thienopyridines
ACS, PCI (in addition to ASA as DAPT), or as an alternative to ASA if patient is allergic
what are the clopidogrel drug interactions
omeprazole, esomeprazole, cimetidine, fluconazole, ketoconazole, voriconazole, etravirine, felbamate, fluoxetine, fluvoxamine
clopidogrel dosing
300-600 mg LD then 75 mg daily
prasugrel dosing
60 mg LD, then 10 mg po daily
adverse events for clopidogrel
bleeding, rash, GI
adverse events for prasugrel
bleeding
what increases the risk of bleeding with prasugrel
history of transient ischemic attack or stroke is a contraindication. older than 75, body weight less than 60 kg
what is the mechanism of the non-thienopyridine, ticagrelor
it is a chemical derivative of nucleosides (ATP). reversibly inhibits P2Y12 receptor. not a prodrug
indications for ticagrelor
reduce risk of cv death/mi/stroke in pts/ w ACS or history of MI (in addition to ASA), reduce risk of stroke in patients with acute ischemic stroke or high-risk transient ischemic attack (in addition to ASA), reduce the risk of a first MI or stroke in patients with CAD
adverse events of ticagrelor
bleeding, dyspnea, bradycardia
drug interactions with ticagrelor
strong CYP3A inhibitors (azole, HIV protease, macrolide), strong CYP3A inducers (anticonvulsants), max simvastatin and lovastatin doses 40 mg
what are the PDE-3 inhibitors
cilostazol and dipyridamole
what is the PAR-1 antagonist
vorapaxar
what is the mechanism for the PDE3 inhibitors
they increase cAMP leading to vasodilation and inhibition of platelet aggregation
what are the indications for cilostazol
peripheral arterial disease ONLY
what is the dosing for cilostazol
100 mg po bid
what are the adverse events for cilostazol
headache, diarrhea, palpitations
when to avoid cilostazol
heart failure
what are the indications for dipyridamole
stroke prevention (aggrenox), prosthetic heart valves (persantine)
what are the adverse events for dipyridamole
headache, GI, dizziness, weakness, peripheral vasodilation, flushing
what is the mechanism for vorapaxar
inhibits thrombin-induced platelet activation via binding to PAR1 receptor. it is reversible at PAR1 but has a long half life of 8 days
what are the indications for vorapaxar
reduction of thrombotic CV events in patients with a history of MI or PAD
what is the dosing regimen for vorapaxar
2.08 mg once daily (2.5 mg vorapaxar sulfate)
vorapaxar must be used in combo with ___
ASA or clopidogrel
contraindications for vorapaxar
TIA, stroke, intracranial hemorrhage
adverse events for vorapaxar
bleeding
drug interactions for vorapaxar
strong CYP3A inhibitors or inducers
