anti clotting

Question 1

Types of anti clotting drugs

Answer 1

• antiplatelet
• anticoagulants
• thombolytics

Question 2

Antiplatelet drugs examples

Answer 2

• aspirin
• platelet GP IIB/IIIA blockers
• ADP receptor blockers
• phosphodiesterase (PDE) blockers

Question 3

aspirin MOA

Answer 3

• irreversible inhibition of COX 1&2 -> TXA2 is not produced, platelet aggregation inhibited

Question 4

aspirin clinical indications

Answer 4

• prophylactic treatment of transient cerebral ischemia
• reduce incidence of recurrent MI
• reduce post MI mortality

Question 5

aspirin adverse effects

Answer 5

• bleeding (no PGI2)
• gastric ulcers (no PGE2), GI bleeding -> dark stools

Question 6

platelet GP IIb/IIIa receptor blocker examples

Answer 6

• abciximab
• eptifibatide
• tirofiban

Question 7

platelet GP IIb/IIIa receptor blocker MOA

Answer 7

• 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

Question 8

GP IIb/IIIa receptor blocker clinical indications

Answer 8

• prevent restenosis after coronary angioplasty
• acute coronary symptoms

Question 9

ADP receptor blockers examples

Answer 9

Clopidogrel, Ticlopidine

Question 10

ADP blocker MOA

Answer 10

• inhibit binding of ADP to ADP receptor, prevent platelet activation and aggregation

Question 11

PDE inhibitors examples

Answer 11

dipyridamole

Question 12

PDE inhibitors MOA

Answer 12

• inhibits degradation of cAMP to 5’-AMP → cAMP is available in platelet for longer → reduce secretion of aggregating agents (serotonin & ADP)

Question 13

Anticoagulants examples

Answer 13

• heparins
• warfarin

Question 14

heparins MOA

Answer 14

• 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

Question 15

Compare PK of regular heparins and LMWHs

Answer 15

LMWHs have better bioavailability and longer Thalf

Question 16

heparin & warfarin clinical uses

Answer 16

• DVT
• pulmonary embolism
• acute MI
• combine with thrombolytics for revascularization
• combine with GP IIb/IIIa inhibitors during angioplasty

Question 17

Can heparin be used in pregnancy?

Answer 17

• yes, it is the only anticoagulant that can be used in pregnancy

Question 18

heparin mode of administration

Answer 18

• IV/ subcutaneous
• NO intramuscular -> cause haematomas

Question 19

Warfarin MOA

Answer 19

• inhibits Vit K reductase, Vit K remains in oxidised form and cannot be used to synthesize factors 2,7,9,10

Question 20

Warfarin PK

Answer 20

• oral administration
• binds strongly to plasma albumin (very small Vd)
• metabolised by P450 (DDI)

Question 21

Warfarin adverse effects

Answer 21

• bleeding
• contraindication in pregnancy

Question 22

Thrombolytics examples

Answer 22

• alteplase (TPA)
• urokinase
• streptokinase
• anistreplase

Question 23

Thrombolytics MOA

Answer 23

• convert plasminogen to plasmin -> degrade fibrin to FDP -> dissolves clot

Question 24

Thombolytics clinical uses

Answer 24

• emergency treatment of coronary artery thrombosis
• ischaemic stroke (<4.5hr window)
• peripheral arterial thombosis/ emboli

Question 25

Thombolytic administration

Answer 25

• intracoronary/ IV injection

Question 26

Thrombolytics adverse effects

Answer 26

• bleeding

Question 27

Thrombolytics contraindicators

Answer 27

• pregnancy
• presence of healing wound

Question 28

vitamin K supplement clinical uses

Answer 28

• 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)