Anticoagulant and Thrombolytic Agents

Question 1

Asprin

Answer 1

nonsteroidal anti-inflammatory drug

blocks platelet cyclo-oxygenase (COX)1 which causes inhibition of thromboxane A2 (TXA2)

Effect is irreversible

Primarily used to treat hypercoagulable states or states of increased platelet reactivity

Question 2

Clopidogrel

Answer 2

Thienopyridine class drug

Blocks adenosine diphosphate (ADP) induced platelet aggregate through binding the platelet P2Y12 receptor

Primarily used to treat hypercoagulable states or states of increased platelet reactivity

Does not remove already formed blood clots

Question 3

Heparins

Answer 3

Naturally occurring - stored within mast cells and released into vasculature at sites of tissue injury

Drug - Unfractionated heparin: heparin sulfate

can be reversed using protamine sulfate

Drug - low molecular weight heparins: Dalteparin and enoxaparin

Does not dissolve preexisting blood clots

Question 4

Enoxaparin

Answer 4

Low molecular heparin

Associated with fewer bleeding events, more predictable absorption and can be given less frequently than UFH

Inhibits factor Xa

Incompletely reversed by protamine sulfate

Question 5

Heparin sulfate

Answer 5

Unfractionated heparin

Binds to antithrombin and inhibits factors IIA, IXa, Xs, XIa, and XIIa
can be reversed using protamine sulfate

Question 6

Direct Factor Xa Inhibitors

Answer 6

Rivaroxaban and apixaban

Does not require antithrombin for factor Xa inhibition and clinical effects

Does not dissolve blood clots that have already formed

Question 7

Rivaroxaban

Answer 7

Trade name: Xarelto

Direct Factor Xa inhibitor

Oral anticoagulant used to prevent or treat thrombosis in high risk patients

Contraindicated in patient with uncontrolled pathologic bleeding, severe hepatic disease, hepatic disease associated with coagulopathy or with significant renal impairment

Question 8

Thombolytics

Answer 8

Drugs: streptokinase, urokinase, tissue plasma activator (t-PA)

Not widespread in vetmed

Should be administered as early as possible to be most effective

contraindicated or inappropriate in situations of known coagulopathy, states of active bleeding, cardiac thrombi, neoplasia that invades the vasculature and infective endocarditis

Complication associated with thrombolytic agents: Bleeding