Anti-platelets and Thrombolytics

Question 1

within the anti-clotting group of drugs are two classes of drugs - what are they?

Answer 1

anti-coagulants and anti-thrombolytics

Question 2

within the anti-clotting group of drugs which drug is typically used to treat arterial disease? (the other is typically used to treat both arterial and venous thrombosis)

Answer 2

anti-coagulants

Question 3

what happens to aPTT time when the drug effect is deemed adequate?

Answer 3

it is prolonged

Question 4

what is the name of the endogenous anti-clottting protein that irreversibly inactivates thrombin - its actions are increased by heparin

Answer 4

antithrombin III

Question 5

this is the laboratory test used to monitor the anticoagulant effect of warfarin; it is prolonged when drug effect is adequate

Answer 5

Prothrombin Time (PT)

Question 6

true or false: heparin is highly acidic and can be neutralized by basic molecules

Answer 6

true

Question 7

true or false: it is safe to give heparin via IV, subcutaneously and IM

Answer 7

false - not safe IM due to risk of hematoma

Question 8

what is the advantage of fractioned (LMW) heparin over un-fractioned heparin?

Answer 8

LMW has greater bioavailability and longer duration of action - this also means it can be given less frequently

Question 9

which one cannot be used during pregnancy? warfarin or heparin?

Answer 9

warfarin

Question 10

which is more fast acting? warfarin or heparin?

Answer 10

heparin

Question 11

true or false: aPTT test does not reliably measure anti-coagulation effect of LMW and other unfractioned heparins (like fondaparinux)

Answer 11

true

Question 12

heparin is used in combination with ____ for re-vascularization

Answer 12

anti-thrombolytics

Question 13

heparin is used in combination with ______ during angioplasty and placement of coronary stents

Answer 13

glycoprotein IIb/IIIa

Question 14

what is the most common adverse side effect of heparin?

Answer 14

increased bleeding which may end in hemorrhagic stroke

Question 15

what is the name of the drug that can lessen the risk of serious bleeding that can result from excessive un-fractioned heparin?

Answer 15

protamine

Question 16

unfractioned heparin can cause moderate transient ____ in many patients.

Answer 16

thrombocytopenia

Question 17

these are used as an alternative to heparin primarily in pts with heparin induced thrombocytopenia.

Answer 17

direct thrombin inhibitors

Question 18

warfarin is approximately what percent bound to plasma proteins?

Answer 18

99%

Question 19

how does warfarin get eliminated from the body?

Answer 19

depends on CYP450 for its metabolism

Question 20

how can you reverse the actions of warfarin?

Answer 20

vitamin k, but remember that the reversal requires synthesis of new normal clotting factors which can take several hours

Question 21

how can you quickly reverse the effects of warfarin ?

Answer 21

transfusion of FFP that contains the normal clotting factors

Question 22

which anti-coagulant will actually give you a brief period hyper-coagulability?

Answer 22

warfarin - this is most likely b/c of the deficiency of protein c

Question 23

which of the anti-coag drugs should you be more concerned about drug-drug interactions?

Answer 23

warfarin - again namely b/c its metabolism is by CYP450

Question 24

what is the effect that CYP450 inducing drugs will have on warfarin therapy?

Answer 24

increase warfarin clearance and reduce the anticoagulation effect of the drug - note then that on the opposite side (CYP450 inhibitors), these drugs would reduce clearance and increase the anti-coagulation effects of the drug.

Question 25

what is the enzyme that directly converts plasminogen to plasmin?

Answer 25

t-PA (tissue plasminogen activator) - remember that it is plasmin that will degrade clots

Question 26

what class does the drug alteplase belong to?

Answer 26

thrombolytic drugs

Question 27

these are able to from a complex with endogenous plasminogen that allows it to covert to plasmin and help dissolve clots.

Answer 27

streptokinase

Question 28

what is one of the more serious side effects of thrombolytics?

Answer 28

cerebral hemorrhage

Question 29

this class of drugs includes: glycoprotein IIb/IIIa receptor inhibitors (abciximab, tirofiban, eptifibatide), antagonists of ADP receptors and inhibitors of phosphodiesterase 3.

Answer 29

antiplatelets

Question 30

NSAIDs and aspirin mainly work by inhibiting what?

Answer 30

thromboxanes synthesis by blocking COX

Question 31

what makes inhibition by aspirin such a powerful anti platelet?

Answer 31

the fact that it binds irreversible to inhibit COX and the fact that platelets lack machinery to synthesis and so they must wait until new ones are made

Question 32

what is commonly treated with oral or parenteral phytonadione?

Answer 32

vitamin k deficiency