Anti clotting Flashcards
Types of anti clotting drugs
- antiplatelet
- anticoagulants
- thombolytics
Antiplatelet drugs examples
- aspirin
- platelet GP IIB/IIIA blockers
- ADP receptor blockers
- phosphodiesterase (PDE) blockers
aspirin MOA
- irreversible inhibition of COX 1&2 -> TXA2 is not produced, platelet aggregation inhibited
aspirin clinical indications
- prophylactic treatment of transient cerebral ischemia
- reduce incidence of recurrent MI
- reduce post MI mortality
aspirin adverse effects
- bleeding (no PGI2)
- gastric ulcers (no PGE2), GI bleeding -> dark stools
platelet GP IIb/IIIa receptor blocker examples
- abciximab
- eptifibatide
- tirofiban
platelet GP IIb/IIIa receptor blocker MOA
- platelet aggregation occurs but platelets do not stick together
abciximab
- humanized monoclonal antibody, prevents fibrinogen binding to GP
eptifibatide
- fibrinogen analog, binds to GP and prevents fibrinogen binding
tirofiban
- small molecule blocker of GP
GP IIb/IIIa receptor blocker clinical indications
- prevent restenosis after coronary angioplasty
- acute coronary symptoms
ADP receptor blockers examples
Clopidogrel, Ticlopidine
ADP blocker MOA
- inhibit binding of ADP to ADP receptor, prevent platelet activation and aggregation
PDE inhibitors examples
dipyridamole
PDE inhibitors MOA
- inhibits degradation of cAMP to 5’-AMP → cAMP is available in platelet for longer → reduce secretion of aggregating agents (serotonin & ADP)
Anticoagulants examples
- heparins
- warfarin
heparins MOA
- induce conformational change of ATIII when bound to it
- inactivate thrombin (fIIa) -> ONLY regular heparin, must be long enough to bind to both ATIII and IIa
- inactivate fXa -> both regular and LMWHs works, necessary for heparin to just bind to ATIII
Compare PK of regular heparins and LMWHs
LMWHs have better bioavailability and longer Thalf
heparin & warfarin clinical uses
- DVT
- pulmonary embolism
- acute MI
- combine with thrombolytics for revascularization
- combine with GP IIb/IIIa inhibitors during angioplasty
Can heparin be used in pregnancy?
- yes, it is the only anticoagulant that can be used in pregnancy
heparin mode of administration
- IV/ subcutaneous
- NO intramuscular -> cause haematomas
Warfarin MOA
- inhibits Vit K reductase, Vit K remains in oxidised form and cannot be used to synthesize factors 2,7,9,10
Warfarin PK
- oral administration
- binds strongly to plasma albumin (very small Vd)
- metabolised by P450 (DDI)
Warfarin adverse effects
- bleeding
- contraindication in pregnancy
Thombolytics examples
- alteplase (TPA)
- urokinase
- streptokinase
- anistreplase
Thombolytics MOA
- convert plasminogen to plasmin -> degrade fibrin to FDP
- dissolves clot
Thombolytics clinical uses
- emergency treatment of coronary artery thrombosis
- peripheral arterial thombosis/ emboli
- ischaemic stroke (<4.5hr window)
Thombolytic administration
- intracoronary/ IV injection
Thrombolytics adverse effects
- bleeding
Thrombolytics contraindicators
- pregnancy
- presence of healing wound
vitamin K supplement clinical uses
- reduced form of Vit K essential for formation of factors 2,7,9,10
- treatment/ prevention of bleeding from warfarin/heparin
- prevent haemorrhagic disease of newborn (when warfarin taken during pregnancy)
