anticoagulants Flashcards
thrombotic disorder
tx with anticoagulants, fibrinolytic
bleeding/hemorrhage
hemophilia tx with coagulation factor and transfusion
vit k def tx with vit k
thrombocytopenia
response to injury
VC
platelet plug
clot formation (secondary hemostasis)
fibrinolysis
keeps platelets in inactive state
NO
prostacylin
ADPase
all inc cAMP in platelets which act. Ca efflux pump to lower Ca
primary hemostasis
collagen and von willebrand leads to platelet adhesion
dec cAMP and inc Ca activates platelets
platelet act.
platelet release thromboxane A2
adenosine diphosphate
serotonin
thrombin
platelet aggregation
inc in GPIIb/IIIa rec on surface of platelet
bind to cirullating fibrinogen
creates platelet plug
anti-platelet drugs targers
inhibition of TxA2 synthesis
inhibition of ADP receptors
blockage of GPIIb/IIIa rec
phosphodiesterase inhibitors/vasodilators
inhibition of TxA2 synthesis
oral aspirin
irreversible inhibition of COX-1
platelet life is 7-10 days
NSAIDS-reversible
dont give at same time
inhibition of ADP receptors
oral clopidogrel
irreversible inhibition of P2Y12 receptor
blockage of GPIIb/IIIa rec
IV abciximab monoclonal Ab
irreversible inhibition of fibrin receptor
phosphodiesterase inhibitors/vasodilators
oral dipryridamole
vasodilator
reversible PDE inhibition inc. cAMP and dec Ca
given in combo w/aspirin to prevent cerebrovascular ischemia
secondary hemostasis
several minute
fibrin stabilizes
PL produce negatively charged polyphosphates that trigger intrinsic pathway
tissue factor triggers extrinsic pathway
Xa act factor II (prothrombin) into factor IIa (thrombin)
cleaves next factor that is Zymogen
factor XIIIa
transglutaminase
antithrombin
AT is a serine protease inhibitor and inactivates the serine proteases of the intrinsic pathway
4 classes of anticoagulant
vit k antagonist
indirect thrombin inh
direct thrombin inh
dircect inh of factor Xa
vit k antagonist
oral warfarin
dicoumarol in clover silage, hemorrhagic disease in cattle
Wisconsin Alumni Research Foundation coumARIN
attacks vit k reductase
SNP can lead to high risk of bleeding so need to monitor
phytonadione (mephyton)
oral vitamin K1
warfarin R isomer
cyp1a2/3A4 inhibitors ciprofloxacin most statins fenofibrate macrolide AB CYP inducers phenytoin
warfarin S isomer
CYP2C9 Metronidazole Amiodarone Azole antifungals Sulfamethoxazole/trimethoprim
indirect thrombin inh
IV unfractionated heparin
SC, IV LMW heparins: Enoxaparin
IV unfractionated heparin
Pentasaccharide sequence binds to AT and exposes it leading to Xa inactivation
short half, continued infusion
SC, IV LMW heparins: Enoxaparin
2,000 to 9,000 daltons
longer half life, infected ONCE daily, NO monitoring needed
protamine sulfate
antidote to heparin
basic, positively charged
Inj
monitored
direct thrombin inh
oral dabigatran DOAC large prodrug reversible inh thrombin serine protease half life of 12-24 hr, once daily
better than warfarin, heparin, and inj thrombin inhibitors b/c there is NO NEED TO MONITOR
dircect inh of factor Xa
oral Rivaroxaban
most recent DOAC
all better choices than warfarin because NO MONITORINg
positive regulators of fibrinolysis
damaged endothelium releasing tissue Plasminogen Activator
tPA binds to plasminogen bound to fibrin rather than circulating plasminogen
tPA cleaves plasminogen into plasmin
fibrinolytic or thrombolytic drugs
IV tPA alteplase
tPAs prefer plasminogen bound to fibrin, fibrinolysis will only occur in the formed thrombus and avoids act in the systemic flow
alteplase
recombinant full length glycosylated human tPA
very fibrin selective
efficient in dissolving older clots
management of DOACS
anti factor Xa assay before sx
no reversal agents so consider cessation of DOAC medication before sx
collagen plug/sponge
acc aggregation of platelets and forms physical barrier
microfibrillar collagen (avitene) collagen sheets
topical thrombin
added to matrix, gelfoam
CAUTION if allergic rx from bovine thrombin
fibrin sealant (fibrin glue)
mix of thrombin and CaCl2 in one syringe, conc of thrombin determines rate of clot
fibrinogen, factor XIII, fibrinogen determines strength of clot
astringents or styptics
VC, induce platelet aluminum chloride (plugs incapillaries) tannic acid (CAUTION incompatible with metal salts)
vasoconstrictor agents
epinephrine
short term bleeding
long term use is ischemia nd tissue necrosis
fibrinolytic inhibitors
maintain clot stability, comp inh plasminogen act
aminocaproic acid
tranexamic acid
cover risk of hemorrhage in ptwith hemophilia (replace with coag factor)
