Flashcards in Antiplatelet, anticoagulant and thombolytic drugs Deck (34):
Where would an arterial thrombus (white thrombus) become lodged?
Brain (stroke) or other organ
Where would a venous (red thombus) become lodged?
Lungs (pulmonary embolus)
In vivo pathway tissue factors
Contact pathway factors
XIIa and IXa
X becomes Xa and what does this to?
Changes prothrombin (II) to thrombin IIa
this then converts fibrinogen to fibrin
What state must vitamin K be in to act as an essential cofactor?
In its reduced form (hydroquinone)
How does warfarin work?
Structurally similar to vitamin K, competes with vit. K for binding to vitamin K reductase
(prevents conversion of epoxide to hydroquinone)
Which factors does warfarin inactivate?
II, VIII, IX and X
Pregnancy, hypothyroidism and clotting factors?
Pregnancy = increased synthesis of clotting factors
Hypothyroidism = decreased degradation of clotting factors
Treatment for overdose of warfarin?
Vitamin K or concentrate of plasma clotting factors
Name 2 LMWH
How is heparin administered?
IV or SC
How are LMWH administered?
How do you determine optimum dosage for heparin?
In vitro clotting
How are LMWH excreted?
Via the kidneys
Heparin inhibits which factors?
IIa and Xa
LMWH inhibits which factor?
Adverse effects of heparin and LMWH?
Direct thrombin inhibitor
Factor Xa inhibitor
How are platelets cross linked?
What are contained in platelet storage granules?
ADP, 5HT and coagulation factors
(TXA2 is synthesised on demand by COX)
Blocks P2Y12 receptor
Blocks IIb/IIa receptor
(blocks COX and so blocks TXA2 synthesis)
Aspirin side effects
GI bleeding and ulceration
How is tirofiban administered?
-used to prevent MI in high risk patients with unstable angina (with aspirin and heparin)
Drugs which activate plasminogen? (plasminogen --> plasmin --> breaks up fibrin)
Why are alteplase and duteplase given IV?
Short half life
Side effect of streptokinase?
Cause allergic reaction