anti-coagulation

Question 1

how does aspirin work as anti-platelet drug for arterial thrombosis?

Answer 1

usually platelet release chemical on activation which sticks to receptor and triggers further platelets accumulation (aspirin blocks production of thromboxin A2 and blocks aggregation of platelets)

Question 2

how does clipidegral and prasugrel act as anti-platelet for arterial thrombosis?

Answer 2

ADP receptor agonists (they block receptor so ADP can’t bind and therefore blocks aggregation of platelets)

Question 3

what is abciximab?

Answer 3

→given by infusion (not common) - can be given at time of cardiac surgery so prevent thromboses

Question 4

what are risk factors for venous thrombosis?

Answer 4

• stasis (not moving - immobile like surgery or unwell means high risk)
• vessel wall (valves deteriorating)
• hypercoagulability (clotting factors involved being pushed up due to inflammatory response)

Question 5

what is problem of atrial fibrillation (irregular rhythm of heart)?

Answer 5

means blood sits in atrium for much longer = stasis = blood clot can form on wall of LA (on itself not problem but embolisation big worry →would block common carotid artery in brain →stroke)

Question 6

how does warfarin act as anti-coagulant for venous thrombosis?

Answer 6

warfarin targets coagulation proteins in 2ndary haemostasis - means no -ve charge of glycoproteins so don’t come together and sit efficiently to make clot = bleeding

Question 7

why use thrombin inhibitors instead of warfarin for venous thrombosis treatment?

Answer 7

• warfarin is very specific and difficult to get perfect dose (if just enough of dose then can reduce clots- if too much then big bleeds - everyone required different dose due to metabolism so needs regular blood tests)

Question 8

how do thrombin inhibitors act as anticoagulants for venous thrombosis?

Answer 8

inhibit thrombin so prevent fibrin production direct and prevent feedback loop

Question 9

how do XA inhibitors act as anticoagulant for venous thrombosis?

Answer 9

inhibit Xa coagulation factor = no thrombin generated so prevent fibrin production direct and prevent feedback loop

Question 10

how does heparin act as anticoagulant for venous thrombosis?

Answer 10

• heparin is anticoagulant drug that emphasises the natural activity of anti-thrombin so switches off thrombin & coagulation factors
• usually by injection or sub-cutaneously
• heparin has rapid onset