coagulation disorders

Question 1

Aspirin

Answer 1

anti-platelet drug, secondary prevention of myocardial infarction, cox inhibition, irreversible inhibition of cox-1, cox inhibitors decrease prostacyclin production and thromboxane production, endothelial cells can create a new cox-1 but platelets are non nucleated so cant causing anti-platelet aggregatory effects

Question 2

iloprost, epoprosterol

Answer 2

prostacyclin analogue, mimics action of prostacyclin

Question 3

ticlopidine, clopidogril

Answer 3

drugs that target the GPIIB/IIIa receptor system, inhibitors of ADP induced GPIIb/IIIa receptor activation, SE: bleeding, nausea, diarrhoea, neutropenia

Question 4

abciximab, tirofiban, eptifibatide

Answer 4

GPIIb/IIIa receptor antagonists, prevents fibrinogen from binding platelets together, SE: bleeding

Question 5

streptokinase

Answer 5

fibrinolytic drugs, treatment of acute thromboembolic disorders e.g. myocardial infarction, promotes the formation of pasmin

Question 6

warfarin

Answer 6

vitamin k antagonist, inhibits reduction of vitamin k, in vivo only, long onset of action, use must be monitored, overdose treated with vit k and clotting factors, warfarin may produce a transient paradoxical effect due to reduced protein C before reduction of clotting factors, the draw backs: slow onset of action, transient pro-coagulatory effect through action on protein c, interactions with food, needs monitoring, SE: haemorrhage, particularly nose, pharynx, Gi, and urinary tract

Question 7

Alteplase, reteplase, tenectoplase

Answer 7

synthetic recombinant version of endogenous tissue plasminogen factor (tPA), selective for plasminogen bound to fibrin within clots, requires intravenous infusion

Question 8

excessive haemorrhage

Answer 8

anti-fibrinolytics, APROTININ inhibits plasmin and used before open heart surgery, TRANEXAMIC ACID inhibits plasminogen activation

Question 9

haemophilia

Answer 9

Haemophilia A - factor VIII deficiency
Haemophilia B - factor IX deficiency
Haemophilia C - factor XI deficiency
symptoms: excess bleeding, easily bruised
Treatment: administration of missing factor

Question 10

Von Willebrands disease

Answer 10

hereditary coagulation abnormality, deficiency of von willebrands factor causing a decrease in platelet adhesion, increased tendency to bleed, often asymptomatic, treatment using vasopressin analogue (desmopressin) which stimulates the release of von willebrand factor from endothelial cells

Question 11

vitamin K deficiency

Answer 11

Found in green veggies, synthesized by gut flora, necessary for synthesis of II, VII, IX, X, and protein C
Cause: lack of gut flora, malnutrition, reduced fat absorption, overdose of warfarin
Treatment: vit K supplements

Question 12

unfractionated heparin

Answer 12

polysaccharides extracted from animal tissue, rapid effect, decreased thrombin induced platelet activation at high doses, and decreases fibrin formation at low doses, inhibits in vivo and in vitro blood clotting, and an overdose is treated with PROTAMINE, MOA: increases the effectiveness of anti-thrombin III on serine protease coagulation factors

Question 13

LMWH

Answer 13

Low molecular weight heparins, does not affect thrombin activity, greater bio-availability than unfractionated heparin, longer half life than unfractionated heparin