Anticoagulants Flashcards
binds with antithrombin 3 and forms a complex irreversible inactivates thrombin and factor Xa
unfractioned heparin
monitored by aPTT (measures function of intrinsic pathway of coagulation cascade
unfractioned heparin
not a clot buster, it will prevent the fibrin clots from forming
heparin
treats
1) DVT prophylaxis
2) acute DVT
3) prophylaxis and acute pulmonary embolism
4) acute MI to prevent extension and formation
Heparin
1) bleeding
2) induced thrombocytopenia (swell foot) - occurs when Ab armada against heparin complex to platelet factor 4
3) hyperaldosteronism
4) hypoaldosteronism causes hyperkalemia
5) osteoporosis
heparin ADR
results in paradoxical thrombosis in the setting of thrombocytopenia
HIT
reverses the anticoagulant effect of unfractioned heparin
protamine sulfate
binds to antithrombin 3: forms complex inhibits factor Xa with less of an effect on thrombin
LMWH
does not require PTT monitoring
has prolonged half life
protamine sulfate less effective
eliminated renally and can stay in system if there is renal insufficiency
LMWH
safe in pregnancy
heparin
lowest risk of HIT
fondaparinux
binds to antithrombin 3 with higher specificity; inhibits factor Xa with less effect on thrombin
fondaparinux
blocks vitamin k epoxide reductase; preventing factors 2 7 9 10 form being produced and also proteins C and S
warfarin
promotes gamma carboxylation
vit K
occurs at glutamic acid residue on factors 2 7 9 10
gamma carboxylation
1st clotting factor to be reduced when starting warfarin
factor 8
onset 8-12 hrs
full clinical effect takes 3 days
oral admin
long half life
warfarin
monitor using PT and INR
warfarin
goal INR is _____ for prevention and treatment of thrombosis
2-3
treats
1) long term anticoagulation in a fib
2) dvt prophylaxis
warfarin
crosses placental barrier and can cause a hemorrhagic disorder or prevent carboxylation reactions in bone
ADR warfarin
anticoagulation protein C is reduced early in warfarin therapy - hypercoagulable state initially
ADR warfarin
induces skin necrosis due to hypercoagulable state
warfarin
coadmic of heparin when starting warfarin prevents the early hypercoagulable state
heparin bridge
warfarin anticoagulation can be reversed with
Vit K
immediate reversal treatment of warfarin anticoagulation
fresh frozen plasma
increase rifampin, phenobarbital, phenytoin
decrease effects of warfarin
decrease antibiotics, antifungals, SSRIs
increase effects of warfarin
direct thrombin inhibitors
argatroban
dabigatran
bivalirudin
directly bind to and irreversibly inhibit thrombin
do not require antithrombin 3
monitor by aPTT
direct thrombin inhibitors
100% metabolized in liver
half life 40-50 min
used in HIT and renal failure
argatroban
renal elimination oral med does not require monitoring used in A fib rapidly reversed by idarucizumab (monoclonal Ab)
dabigatran
can replace heparin
treats HIT
20% renal elimination(rest metabolic)
bivalirudin
specific irreversible thrombin (2a) inhibitor from leech saliva
hirudin
IV
renal elimination
use to treat HIT
lepirudin
direct factor Xa inhibitors
rivaroxaban and other xabans
does not require monitoring
half life - ~10 hrs
no antidote
given in fixed doses
rivaroxaban and other xabans
used to prevent DVTs
prevention of stroke and systemic embolism in non valvular atrial fib
rivaroxaban and other xabans
dont use in kidney or liver dysfunction
25-50% renal metabolism
use P450 and P glycoprotein for metabolism and excretion
rivaroxaban and other xabans
lyse thrombi by catalyzing the formation of the endogenous fibrinolytic plasmin from plasminogen
fibrinolytics
not clot specific
helps activate plasminogen to plasmin
antigenic (derived by streptococci)
streptokinase
clot specific
acting mainly on fibrin bound plasminogen
natural activator
alteplase (tPA)
antidotes in excessive bleeding
antifibrinolysins (aminocaproic and tranexamic acids)
decreases TXA2
irreversibly inhibits COX 1 in platelets - decreases activation
low doses prevent MI and recurrence; prophylaxis in Atrial arryh and TIAs
aspirin
stop before surgery and pregnancy
increases GI bleeding 2x over placebo
aspirin
block ADP receptors on platelets - decrease activation (irreversibly)
clopidogrel
prasugrel
ticagrelor
alternatives to ASA in TIAs, post MI, and unstable angina
clopidogrel
prasugrel
ticagrelor
ADR
1) hemorrhage
2) leukopenia
3) thrombocytopenia purpura
clopidogrel
prasugrel
ticagrelor
most effective anti platelet and a monoclonal Ab
Abciximab
antagonists that bind to glycoprotein 2b/3a receptors - decrease aggregation by preventing the cross linking reaction
inhibit final common pathway
Abciximab
eptifibatide
tirofiban
used mainly in acute coronary syndrome and postangioplasty
Abciximab
eptifibatide
tirofiban
mimic Glanzmanns thrombasthenia and bernard soulier syndrome
Bp 2b/3a receptor blockers
inhibit adenosine uptake to RBC = increase adenosine in blood
dipyridamole
inhibits cGMP phosphodiesterase activity , increasing cGMP - vasodilation
dipyridamole
combine with aspirin to treat TIA; no effect alone
dipyridamole
cAMP phosphodiesterase 3 inhibit - increase cAMP - platelet aggregation inhibit and vasodilation
cilostazol
treats intermittent claudication (leriche syndrome)
cilostazol
