Anticoagulants II

Question 1

what is the coumarin anticoagulant and how does it work

Answer 1

warfarin, an oral anticoagulant (unlike heparin)

inhibits vit K epoxide reductase leading to production of inactive clotting factors II, VII, IX, X since they lack the gamma carboxyl glutamic side chain

Question 2

warfarin’s effect on thrombus

Answer 2

has no effect on pre established thrombus but will further prevent increase in the size of the thrombus

Question 3

how to overcome warfarin

Answer 3

give vitamin K and see reversed changes in 24 hours

Question 4

why must warfarin be monitored and how is it monitored

Answer 4

has a narrow therapeutic window

measured using PT which measure extrinsic and common pathway of coagulation

Question 5

uses of warfarin

Answer 5

• warfarin used to prevent progression or recurrence of DVT or PE after initial heparin use
• prevent venous thromboembolism
• given with initial heparin, fondaparinux, or LMWH which is discontinued once INR is in therapeutic range for two straight days

Question 6

adverse effects of warfarin

Answer 6

• hemorrhage
• cutaneous necrosis due to reduced activity of protein C
• crosses placenta and cause hemorrhagic disorder in fetus and abnormal bone formation

SO DO NOT GIVE TO PREGGOS

Question 7

drugs that inhibit warfarin metabolism and what they cause

Answer 7

Cimetidine, Chloramphenicol, Disulfarim, Fluconazole, Metronidazole, Phenylbutazone, Sulfinpyrazone, TMP-SMX (trimethoprim-sulfamethoxazole)

CC-DF-MP-ST

potentiate anticoagulation –> bleeding

Question 8

drugs that stimulate warfarin metabolism and what they cause

Answer 8

barbiturates, carbamazepine, phenytoin, rifampin

RiP CB

reduce anticoagulation

Question 9

what are the thrombolytic drugs

Answer 9

STUART

Streptokinase, Thrombolytics, Urokinase, Alteplase, Reteplase, Tenecteplase

Question 10

mechanism of thrombolytics

Answer 10

convert inactive zymogen plasminogen to active protease plasmin which then digests fibrin –> lysing of already formed blood clots

Question 11

who are thrombolytics contraindicated in

Answer 11

healing wounds
pregnancy
history of cerebrovascular accident
metastatic cancer

Question 12

what is streptokinase produced by and what does it catalyze the degradation of

Answer 12

produced by beta hemolytic strep

degrades fibrinogen, factor V and VII

Question 13

what is streptokinase used for

Answer 13

acute MI
acute PE
arterial thrombosis
occluded access shunts

Question 14

what is Urokinase found and what is it used for

Answer 14

• since it is synthesized by kidney, it is found in urine

- used for lysis of PE

Question 15

how does Alteplase, Reteplase, and Tenecteplase work

Answer 15

they are tissue plasminogen activator (t-Pa) (serine protease) that rapidly activate plasminogen already bound to fibrin in a thrombus

poor activators of free plasminogen

Question 16

what does higher concentration of tissue plasminogen (t-Pa) lead to

Answer 16

activation of circulating plasminogen –> hemorrhage

Question 17

uses of alteplase, reteplase, and tenecteplase

Answer 17

alteplase: acute MI and acute ischemic stroke

reteplase and tenecteplase: acute MI

Question 18

how do you prevent and treat venous thrombosis

Answer 18

with LMWH, UFH, or fondaparinux

-could also use warfarin but must monitor

Question 19

drugs used to treat arterial thrombosis

Answer 19

aspirin and clopidogrel

Question 20

what are the drugs used to treat bleeding

Answer 20

VAPP
Vit K, Aminocaproic acid, Protamine sulfate, plasma fractions

all plasminogen activation inhibitors

Question 21

how does aminocaproic acid and tranexamic acid work

Answer 21

synthetic inhibitors of fibrinolysis which competitively inhibit plasminogen activation

Question 22

what is aminocaproic acid and tranexamic acid used for

Answer 22

adjunct therapy in hemophilia

therapy for bleeding from fibrinolytic therapy

Question 23

adverse effect of aminocaproic acid and tranexamic acid

Answer 23

intravascular thrombosis

Question 24

mechanism of protamine sulfate

Answer 24

chemical antagonist of heparin hence inactive against fondaparinux

Question 25

adverse effects of protamine sulfate

Answer 25

hypersensitivity
dyspnea
flushing
bradycardia
hypotension

Question 26

when is vit k an excellent choice to stop bleeding

Answer 26

if vit K deficiency

on warfarin therapy