anticoagulants and hemostatic agents

Question 1

what breaks down clot formation

Answer 1

fibrinolysis

Question 2

what factor activates Factor I (Fibrinogen) to form a clot

Answer 2

factor II (thrombin)

Question 3

what is the intrinsic clotting pathway

Question 4

what patients are candidates for Anticaogulants

Answer 4

Hypercoaguable/Thromboembolic states
* cats w/ hypertrophic CM
* dogs w/ immune mediated hemolytic anemia
* cushing’s dz
* acute phase inflammation
* protein losing nephropathy

Question 5

what patients are candidates for hemostatic agents

Answer 5

Hypocoaguable states
* post Sx, trauma, intoxication
* genetic bleeding diatheses
* liver intoxication/failure
* disseminated intravascular coagulopathy

Question 6

What is the indicated use for Warfarin sodium

Answer 6

prophylactic txt of thrombotic conditions
use is HIGLY CONTROVERSIAL

Question 7

what it the MOA of Warfarin

Answer 7

blocks recycling of gamma glutamyl carboxylase vit k (oxidized) back into its reduced form

recycling is caused by vit k epoxide reductase

Question 8

Warfarin toxicity

Answer 8

• Narrow TI
• fatal hemorrhage associated w/ anemia
• hematomas can form in any system

Question 9

Warfarin use requires the VERY FREQUENT monitoring of what

Answer 9

prothrombin time

Question 10

indicated use of Vitamin K1

Answer 10

• rodenticide toxicity and moldy sweet clover
• prolonged sulfonamide txt of birds for coccidiosis

Question 11

why won’t vitamin K1 work in patients w/ chronic liver failure

Answer 11

the liver synthesizes coagulation factors

Question 12

how does vitamin K1 work

Answer 12

gets conjugated to newly synthesized gamma glutamyl carboxylase in the liver by dI-diaphorase (makes new gamma glutamyl carboxylase)

Question 13

Vit K1 administration

Answer 13

PO in dogs w/ fatty meal
IM or SC in food animals

therapeutic effects occur 6-12 hrs post admin

Question 14

toxicity/adverse effects of Vit K

Answer 14

ANAPHYLAXIS

Question 15

Heparin soidum vs Enoxaparin Na & Dalteparin Na

Answer 15

Heparin is a large glycosaminoglycan compared to Enoxaparin & Dalteparin which are low molecular weight heparin fractions

Heparin has a tail that allows for the shut down of both Factor Xa and thrombin but the other drugs lack a tail and can only shut down factor Xa

Question 16

admin of heparin

Answer 16

IV
SC if LMWH (enoxaparin / dalteparin)

Question 17

metabolism of heparin

Answer 17

liver & reticuloendothelial system/macrophages

Question 18

heparin distribution

Answer 18

largely confined to circulation

Question 19

what can occur from IM and deep SC administration of heparin

Answer 19

hematomas

Question 20

heparin requires the presence of what to work

Answer 20

anti-thrombin III
so won’t work in animals w/ protein losing nephropathy

Question 21

non-specific binding of heparin to platelets causes…

Answer 21

immune mediated thrombocytopenia and platelet activation (heparin induced trhombocytopenia)

Question 22

competitive inhibitor of Factor Xa that does NOT require anti-thrombin III to work

Answer 22

Rivaroxaban

Question 23

Acetysalicylic acid is..

Answer 23

aspirin

Question 24

MOA of acetylsalicyclic acid

Answer 24

irreversible inhibition of COX1, preventing thromboxane A2 production

TxA2 is needed to make platelets angry

Question 25

administration of acetylsalicyclic acid

Answer 25

PO, 70% BA in dogs

Question 26

metabolism of acetylsalicyclic acid

Answer 26

converted to salicylate by plasma esterases modified by secondary metabolism in the liver via **glucoronidation & glycine modification**

Question 27

elimination of acetylsalicyclic acid

Answer 27

renal - urinary acidifying agents reduce elimination, alkalinizing agents increase elimination

Question 28

why is the elimination time of acetylsalicyclic acid in cats so high (38hrs)

Answer 28

b/c its metabolism requires glucoronidation and cats don't glucoronidate

Question 29

acetylsalicyclic acid overdose

Answer 29

* life threatening metabolic acidosis, depression, V+, hyperventilation, hyperthermia * GI ulceration * nephrotoxicity

Question 30

acetylsalicyclic acid contraindications

Answer 30

* being a cat * hemorrhagic disroders * kidney or liver insufficiency * other drugs w/ high plasma protein binding * surfical procedures

Question 31

this drug doubles survival compared to aspirin in cats w/ risk of **cardiogenic embolism caused by hypertrophic cardiomyopathy**

Answer 31

Clopidogrel bisulfate

Question 32

how does Clopidogrel bisulfate work

Answer 32

irreversibly inhibits platelet ADP receptors = less activated platelets = less clotting

Question 33

T/F: Clopidogrel bisulfate is a prodrug and has to be activated by first pass metabolism

Answer 33

True

Question 34

what are the 2 types of clot forming topicals

Answer 34

type 1: activate a patient's own platelets type 2: injection of fibrogen and an activating agent to casue quick clot formation

Question 35

what is collasate

Answer 35

type 1 collagen foam (activates patients platelets) by **binding to their collagen receptor**

Question 36

the process of Fibrinogen → fibrin is called

Answer 36

coagulation

Question 37

the breakdown of fibrin into fibrin breakdown products / D-dimers is called

Answer 37

Fibrinolysis

Question 38

what is tissue plasminogen activator

Answer 38

* used for pulmonary or arterial thromboembolism (clots) * activates breakdown of fibrin → fibrin breakdown pdts * highly controversial, most patients die and if they survive, very few regain functional limb use

Question 39

what do Aminocaproic and Tranexamic acids do

Answer 39

inhibit the activity of plasmin / fibrinolysis, prevent the breakdown of clots

Question 40

what is the use of Aminocaproic acid

Answer 40

ELU in dogs and horses - post surgery bleeding - guttural pouch bleeding in horses IV admin

Question 41

use of Tranexamic acid

Answer 41

* ELU for post surgery bleeding in dogs and cats * IV admin * significantly more effective than aminocaproic acid in vitro

Question 42

Adverse effects of Tranexamic acid

Answer 42

V+ in dogs

Question 43

what are the Anti-fibrolytic drugs

Answer 43

* Aminocaproic acid * Tranexamic acid

Question 44

what drugs are anti-coagulator factors

Answer 44

* warfarin * heparins * rivaroxaban

Question 45

what drugs are used for anti-platelet formation

Answer 45

* aspirin * clopidogrel