Antifibrinolytics, protamine, and DDAVP

Question 1

Antifibrinolytic medications work by

Answer 1

preventing the lysis of fibrin- promoting clot formation

Question 2

Antifibrinolytics are used to treat

Answer 2

prevent and treat excessive bleeding as inhibitors of fibrinolysis

Question 3

Antifibrinolytic medications interfere with

Answer 3

the formation of the fibrinolytic enzyme plasmin from its precursor plasminogen by plasminogen activators which takes place mainly in lysine rich areas on the surface of fibrin

Question 4

There are two types of antifibrinolytic medictions:

Answer 4

lysine analogs- tranexamic acid or aminocaproic acid or serine protease inhibitor (aprotinin)- no longer available

Question 5

Epsilon aminocaproic acid is also know as

Answer 5

Amicar

Question 6

Aminocaproic acid is used for

Answer 6

the treatment of acute bleeding due to elevated fibrinolytic activity

Question 7

Amincaproic acid works by

Answer 7

inhibiting the proteolytic enzyme plasmin, the enzyme responsible for fibrinolysis

Question 8

Clinical uses of aminocaproic acid include

Answer 8

trauma, CPB, and spinal fusions

Question 9

Tranexamic acid or TXA is a

Answer 9

synthetic analog of the amino acid lysine

Question 10

TXA works by

Answer 10

inhibiting fibrinolysis by competitively binding to the lysine receptors sites on plasminogen
this prevents plasmin from binding to and degrading fibrin which preserves the fibrin matrix structure

Question 11

Parental TXA is effective in treating

Answer 11

bleeding from multiple causes such as GI, surgical and trauma

Question 12

TXA is (potency)

Answer 12

8-10 times more potent than aminocaproic acid

Question 13

Specific clinical uses of TXA include

Answer 13

Non-cerebral trauma (beneficial within first 3 hours), pediatrics (spinal fusions, craniosynostosis), orthopedic procedures (common in joint procedures), cardiac, obstetrics (massive transfusion algorithm)

Question 14

Crash 2 trial

Answer 14

20,000 adults with traumatic bleeding and TXA reduces death due to bleeding with no increase in vascular occlusive events
tx. within 3 hours of injury

Question 15

Contraindications to TXA include

Answer 15

anaphylaxis, subarachnoid hemorrhage- associated with cerebral infarction, active intravascular clotting (PE, DVT, embolic cerebral stroke)

Question 16

Precautions with TXA include

Answer 16

eliminated unchanged in urine so need to decrease does in pts with renal impairment
UTI- obstruction d/t clot formation
hypotension with rapid IV injection
Color vision defect- visual changes as an indicator of toxicity
seizure disorders
concomitant administration with factor concentrates

Question 17

Protamine is obtained from

Answer 17

sperm of salmon

Question 18

Protamine works by

Answer 18

positively charged alkaline protamine combines with the negatively charged acidic heparin to form a stable complex void of anticoagulant activity

Question 19

Heparin-protamine complex is removed by

Answer 19

reticuloendothelial system

Question 20

The dosage of protamine is

Answer 20

1-1.5 mg for every 100 units of heparin

guided also by the last ACT and estimated amount of total IV heparin administered within the last 2 hours

Question 21

Protamine adverse response include:

Answer 21

hypotension (rapid IV injection leads to histamine release)
pulmonary HTN- protamine-heparin complex can result in complement activation and thromboxane release= pulmonary constriction
allergic reactions

Question 22

Options for patients with allergic reactions to protamine

Answer 22

options are limited
pretreatment with histamine receptor antagonists followed by a slow trial
completely avoid protamine, and allow heparin effect to dissipate (takes hours, risk for bleeding and blood transfusions)
administer alternative to heparin

Question 23

Patients at risk for true allergy to protamine include (ranked from high to low)

Answer 23

prior reaction to protamine
allergy to true (vertebrae fish)
exposure to NPH insulin
allergy to any drug

Question 24

DDAVP is also known as

Answer 24

d-amino-d-arginine vasopressin

Question 25

DDAVP is a

Answer 25

synthetic analogue of the natural hormone arginine vasopressin

Question 26

DDAVP works by causing

Answer 26

release of endogenous store of FVIII and von Willebrand
vWF is a protein that is required for platelets adhesion by acting as a bridge between platelet glycoprotein 1b receptors and damaged subendothelium

Question 27

Dosage of DDAVP includes

Answer 27

0.3 mcg/kg IV infusion over 15-30 minutes

Question 28

Platelet adhesion with DDAVP increases within

Answer 28

30 minutes

Question 29

DDAVP (potency

Answer 29

DDAVP has shown to be more potent than arginine vasopressin in increasing plasma levels of factor VIII activity in patients with von Willebrand’s disease

Question 30

The change in structure of arginine vasopressin to DDAVP results in

Answer 30

decreased in antidiuretic and vasopressin action on smooth muscle

Question 31

The most common side effect of DDAVP is:

Answer 31

hypotension

Question 32

Contraindications to DDAVP include

Answer 32

hypersensitivity
patients with moderate to severe renal impairment
patients with hyponatremia

Question 33

Clinical uses of antifibrinolytics and procoagulants include

Answer 33

aiding in hemostasis

Question 34

Protamine binds to

Answer 34

heparin to create a complex void of anticoagulant activity- it is used to clinically reverse the effects of heparin

Question 35

TXA is an

Answer 35

antifibrinolytic and leads to a reduced bleeding rate

Question 36

Desmopressin is used to

Answer 36

improve platelet function by releasing endogenous von Willebrand