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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