Anticoagulants

Question 1

what is an INR range when you can switch from heparin + warfarin to warfarin alone?

Answer 1

INR: 2-3 therapeutic range

Question 2

Compare contrast warfarin/heparin:
Admin
Half life
Onset of action
Antidote for OD
Measurement of action
Teratogenicity

Answer 2

Heparin: IV or subcu admin; Warfarin: oral admin
Heparin: short half life; Warfarin: long half life
Heparin: rapid onset of action; Warfarin: slow onset
Heparin: protamine sulfate; Warfarin: fresh frozen plasma, Vit K
Heparin: monitor PTT; Warfarin: monitor PT
Heparin: doesn’t cross placenta; Warfarin: teratogenic

Question 3

Which 2 things does heparin decrease in its MOA?

Answer 3

stimulates anti-thrombin

decreases thrombin and factor 10a

Question 4

What is a serious complication of heparin at times?

Answer 4

HIT: heparin induced thrombocytopenia
heparin attaches to platelet factor 4. IgG antibody against that.
Get clotting everywhere and consumptive thrombocytopenia

Question 5

How should you manage the thrombosis during HIT?

Answer 5

stop heparin

use direct thrombin inhibitor, like bivalirudin or argatroban

Question 6

What is enoxaparin and dalteparin?

Answer 6

LMWH
along w/ fondaparinux
act more on decreasing Factor 10a
longer half life
don't need to monitor, can give subcu
if you needed to monitor--take a lot at 10a activity

Question 7

What are the direct thrombin inhibitors?

Answer 7

bivalirudin, lepirudin, desirudin: from hirudin taken from leeches. Inhibits thrombin directly.

Argatroban, dabigatran–other direct thrombin inhibitors.

Question 8

What is the exact MOA of warfarin?

Answer 8

inhibits epoxide reductase that gamma carboxylates Vit K depending clotting factors

Gene: VKORCL

Question 9

What is one crazy side effect of warfarin?

Answer 9

skin/tissue necrosis due to small vessel micro thromboses

higher rate of this seen in Protein C/S deficiency

Question 10

What are the structures of heparin and warfarin?

Answer 10

heparin: large, anionic, acidic polymer
warfarin: small, amphipathic molecule

Question 11

What are the direct factor 10a inhibitors?

Answer 11

rivaroxaban
apixaban
good for DVT, PE, afib
don’t require a bunch of monitoring

Question 12

What is the MOA of the thrombolytics?

Answer 12

convert plasminogen–>plasmin. This cleaves thrombin and breaks down fibrin clots.

Question 13

What happens to labs after admin of thrombolytics?

Answer 13

increase in PT, PTT. NO change in platelet count

Question 14

What is the antidote to OD on streptokinase or tpa?

Answer 14

aminocaproic acid