Antiplatelets& Anticoagulants Flashcards
How do anticoagulants work?
They act at different sites of the coagulation cascade
What is the MOA of Aspirin?
COX inhibtor in the prostaglandin synthesis pathway.
Lowdoseinhbits COX-1 and so platelet aggregation (TXA2)
At larger doses it can also inhibt COX-2
What are oral thienopyridines?
Clopidogrel, Ticagrelor, Ticlopidine, Prasugrel#
They selectively inhibt adenosine diphosphate-induced platelet aggregation
What do you do if INR >8 on Warfarin?
> 8INR with no bleeding
Stop warfarin & give oral vit K
8INR with minor bleeding
Stop Warfarin, give a slow IV of Vit K
Dose of Vit K can be repeated in 24hrs if INR still high
Restart Warfarin when INR <5
What do you do in high INR 5-8 on Warfarin?
Stop Warfarin
5-8 with minor bleeding - give slow IV of Vit K
5-8 with no bleeding - withhold a few doses & reduce maintenance dose
Restart Warfarin when INR <5
What do you do in major bleeding when on Warfarin?
Stop Warfarin
Administer IV Vit K
Prothrombin complex or fresh plasma
What are 2 key side effects of anticoagulants?
Bleeding
Thrombocytopaenia
What is a heparin or dalteparin overdose treated with?
Protamine sulfate
What monitoring is needed in Heparin?
Dosage is adjusted according to activated partial thromboplastin time (APTT)
How is Heparin given? Why?
BY SC or IV due its short halflife of 40-90 min
What monitoring is needed with Warfarin?
INR
this is derived from Prothrombin time
What is the MOA of low-molecular weight heparin
e.g. dalteparin
Accelarates the action of antithrombin III increasing inactivation of factor Xa
What is another name for factor IIa
Thrombin
What is the MOA of Heparin?
Accelarates the action of antithrombin III increasing inactivation of factors IIa and Xa
Smaller effect on IXa, XIa & XIIa
What is the MOA of Warfarin?
Inhibits the reduction of Vit K
prevents the y-carboxylation of glutamate so inhibits factos II, VII, IX & X
to remember; II plus VII = IX and then X
