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6. which is false of Vit K
- the activation of clotting factors is Na dependant
- Vit K is an important co factor in the synthesis of functional clotting factors
- Vit K is fat soluble
- Vit Ks action on clotting factors is crucial for their Ca binding properties
7. warfarin pharmacodynamics which is false
- does not effect clotting factors already made
- Vit K can be given to reverse the effects
- sometiemes referred to as the Vit K agonist
- warfarin competes with Vit K for the reductase enzyme which activates vit K
- warfarin takes 48-72hrs to work
8. warfarin pharmacokinetics which is false
- causes competition with other drugs due to its protein binding capacities
- large volume of distribution
- monitored by prothrombin time or INR
- heavily bound to plasma proteins 99% to albumin
- involves phase metabolisim
9. drug interactions of warfarin
- drugs which inhibit CYP450 enzymes used by warfarin increase the risk of bleeding
- drugs which have an antiplatlet effect may enhance the effect of warfarin
- drugs which dispalce warfarin from binding sites cause more free warfarin
- drugs which induce the CYP450 will reduce the effects of morphine
10. heparin which is false
- can take days to work
- increases the number of antthrombin IIIa natural inhibitor of Xa and thrombin
- antithrombin III acts by binding to thrombin and other factors in the cascade preventing the next factor being activated
- heparin changes the shape of antithrombin III incraesing its affinity to thrombin and other factors
11. which is false of the pharmacokinetics
- unfractionated is large in size and polar in nature given SC or IV
- LMWH is cleared by the kidneys
- adverse effects osteoporosis and haemorrhage
- LMWH is smaller in size and a longer half life
- can be reversed by Vit K
12. which is false of the role of platlets
- occurs due to the binding of the glycoprotein Ia IIb receptors on the surface of the platlets to proteins exposed in the endothelium
- normally only adhere to the epithelium following damage
- adhered platlets secrete chemicals
- the receptors exposed is where fribinogen binds
13. which is false of aspirin
- platlets do not have a nucleus so cannot create more cycloxygenase
- reversibly inhibits enzyme cycloxygenase
- ineffective in the prevention of MI and stroke
- regular low dose aspirin perminatly inhibits platlet production of TXA2 and reduces platlet coagulation
14. adverse effects of aspirin which is false
- a pro drug
- reyes syndrome in under 16yrs
- GI haemorrahage due to inhibition of prostogladins
- can cause bronchoconstriction