Anti-coags Flashcards
What are the 4 oral anti-platelet drugs?
Aspirin, clopidogrel, Ticgrelor, dipyridamole + ASA
ASA MOA?
Irreversibly acetylates COX, preventing platelet syn of TXA2 and thus platelet aggregation
3 non-cardio uses of ASA?
anti-pyretic, analgesic, anti-inflamm
PK of ASA?
half = 2-3 hours; Tx effect = 7-10 days (life of platelet)
MOA of clopidogrel and ticagrelor? Difference?
Antagonist of ADP receptor P2Y12 on platelets - prevents ADP induced cAMP decrease and subsequent aggregation
C is irreversible, T is reversible
Half life and metabolism of clopidogrel?
- t1/2 = 7-10 days (irreversible)
- CYP2C19 pro-drug metal (some are ‘slow’ metabolizers, inhibited by omeprazole)
Half life and metab of ticagrelor?
- active drug
- 7 hours (9 for active metabolite)
- CYP3A metabolism (watch for inducers, inhibitors)
MOA of dipyridamole? Why combine with ASA?
- blocks adenine uptake, inhibits phoshodiesterase (increased cAMP, decreased aggregation, vasodilation)
- not very effective alone
What anti-platelet drug is parenteral?
Abciximab
Dual f(x)/MOA of Abciximab?
- antagonist of GP IIb/IIIa – prevents fibrinogen and vWF from binding platelets
- prevents PT binding to platelets, decreasing thrombin formed = ANTI-COAG
Half life of abciximab?
free drug = 30 min bound drug = 18-24 hours platelet f(x) returns in 48 hours
What are the parenteral anti-coagulants?
Heparin, enoxaparin, fondaparinux, bivalirudin
How does UFH work?
Complexes with AT, increasing its activity – inactivation of IIa, IXa, Xa
How is UFH administered?
IV or SC - large molecules
Half life of heparin? Monitoring?
DOSE DEPENDENT - 30-150 min
Must monitor using aPTT
Three AE’s of heparin?
- HI thrombocytopenia
- heparin hypersensitivity
- osteoporosis
Heparin antidote?
protamine sulfate
What kind of drug is enoxaparin?
- LMWH
- complexes AT increasing its activity – inactivates Xa ONLY
How do LMWH’s compare to UFH pharmacokinetically?
- longer t1/2 = 3-6 hours
- equally efficacious
- greater SC bioavailability (fewer doses)
- more predictable levels/PK - Xa monitoring not required
What is fondaparniux? Administration? Metabolism?
- synthetic heparin-like pentasaccharide
- SC
- t1/2 = 17 HOURS 1x day injection
aPTT therapeutic goal in heparin Tx?
2-3x patient’s normal aPTT
Bivalirudin MOA and metabolism?
direct irreversible inhibition of circulating and clot-bound thrombin
IV infusion t1/2 = 25 MINUTES
When is bivalirudin indicated?
Pt’s who require hep but have had HIT; microvascular surgery to re-attach digits
Which coag factors depend on Vitamin K?
2, 7, 9, 10, C, S
