Drugs affecting hemostasis: 1) Anti-platelet drugs Flashcards
Aspirin
- most commonly used
- will not dissolve an existing clot; only prevents new ones and ones from growing
- best absorbed in the stomach
- t1/2: 15-20
- irreversibly binds to cox-1
Aspirin dosing for acute MI
Increase dose for ppl who are undergoing and acute MI to turn off any new platelets being made (10% recovered daily) or any active platelets in circulation
-give crushed or chewable so it gets to blood stream faster
Aspirin adverse effects
- GI bleeding
- hemorrhagic stroke- in PTs with low risk of heart attack
- dyspepsia/heart burn
- other bleeding
Aspirin
MOA
Irreversibly binds to cox-1 enzyme and blocks Thrombaxane-A2 (TxA2)= prevents platelets from storing/ releasing TxA2= decreases the activation of other platelets= no platelet aggregation
ADP (PY12) Inhibitors
MOA
* high variability
Prevent ADP-dependent platelet activation
- blocks P2Y12 receptors on platelets= no platelet activation
- used in post stent/Cath labs for PTs (+aspirin)
Clopidogrel (plavix)
Prasurgrel (effient)
Ticagrelor (brillinta)
Congrelor
ADP (P2Y12) inhibitors
Cilostazol (pletal)
Dipyridamole (persantine)
Other anti platelet drugs
* used in PTs who don’t respond to other anti platelet drugs, when used alone there is less fxn on platelets
*Clopidrogrel (plavix)
- high variability
- genetic variations
- drug inx: PPIs
- must be activated to active metabolite by liver by CYP enzyme
- 75mg/day normal dose
- onset: 2 hours
Prasugrel (effient)
ADP (P2Y12) inhibitor
- fast onset
- avoid in PTs >75 yrs old
- does NOT have genetically variable activation: less variability
Ticagrelor (brillinta)
ADP (P2Y12) inhibitor
- reversible
- dose BID, use with aspirin 75-100mg
- fast onset
- does NOT have genetically variable activation: less variability
Ticagrelor (brillinta)
Adverse effects/risks
- increased Uric acid conc
- dyspnea
- worry with bleeding risk with surgery bc of reversible binding
Congrelor
ADP (P2Y12) inhibitor
- IV administration
- reversible
- does NOT have genetically variable activation: less variability
- worry with bleeding risk with surgery bc of reversible binding
Anti platelet drugs are used in which patients?
- MI or risk of MI
- stroke or risk of stroke
- heart procedure patients
Cilostazol (pletal)
Other anti platelet drug
Inhibits PDE3… Increases cAMP= impaired platelet fxn
- avoid in heart failure
- dizziness, diarrhea, leukopenia
Dipyridamole (persantine)
Other antiplatelet drug
- marketed in combo with aspirin (aggrenox)
- inhibuts adenosine deaminase and PDE
- increase cAMP, adenosine= lowers platelet fxn and causes vasodilation.
- orthostatic hypotension, dizziness, flushing, may increase angina
