284b anticoagulants

Question 1

Heparin - structure? mechanism?

Answer 1

highly variable length - 5 polysaccharides bind antithrombin and activate it
binds plasma proteins b/c - charge

cofactor for antithrombin –> decreases thrombin (requires long chain) and Xa (only requires short chain)

Question 2

Heparin - use? what test?

Answer 2

IV –> PE, MI, DVT
good for prego b/c doesn’t cross placenta

follow PTT

Question 3

Heparin -toxicity? reversal?

Answer 3

bleeding

HIT –> IgG to PF4-EP –> activates platelets –> thrombosis and thrombocytopenia

osteoporosis

Rx - protamine sulfate (+ charges binds - heparin)

Question 4

Low Weight Heparin - structure? names? benefits?

Answer 4

smaller - no extra tail –> Xa only, little thrombin

enoxaparin
dalteparin
tinzaparin

longer t 1/2, sub Q injections –> bruising
doesn’t bind protein –> no monitoring
can’t reverse

Question 5

warfarin - mechanism? which pathway is followed? with what test?

Answer 5

–I Vit K epoxide reductase (reduces Vit K) – used for II, VII, IX, X, C, S (C, S, VII have short t 1/2 –> tissue necrosis early on)

extrinsic pathway

increases PT

Question 6

warfarin - use?

Answer 6

chronic anticoagulation (STEMI, AFIB)
DONT USE IN PREG CHICKS

follow PT/INR

Question 7

warfarin - toxicity? reversal?

Answer 7

bleeding
teratogenic
skin/tissue necrosis (low C/S early)

Rx - fresh frozen plasma for immediate, Vit K for overdose/non-life threatening bleeding

Question 8

direct factor Xa inhibitors - names? benefits?

Answer 8

Apixaban
rivaroxaban

don’t have to monitor
oral
no reversal

Question 9

direct thrombin inhibitors - names?

Answer 9

from hirudin –> argatroban, bivalirudin , dabigatran

no antidotes