A - 17. Drugs used in coagulation disorders II: Anticoagulant drugs

Question 1

Thrombin (IIa) role

Answer 1

Activates platelets further
Activates factor V, VIII, cofactors
Activates fibrinogen -> fibrin

Question 2

Direct thrombin inhibitor names

Answer 2

bivalirudin (IV)

dabigatran-etexilate (oral)

Question 3

Direct thrombin inhibitor indications

Answer 3

Used in combo with anti-aggregates and in HIT (heparin induced thrombocytopenia)

Should NOT be discontinued suddenly

Question 4

Direct thrombin inhibitor reversal agent

Answer 4

Idarucizumab

Question 5

Direct Xa inhibitor names

Answer 5

Rivaroxaban (oral)

Question 6

Direct Xa inhibitor indications

Answer 6

Treatment of DVT, pulmonary embolism, stroke

Question 7

Direct Xa inhibitors vs warfarin

Answer 7

Direct Xa inhibitors

• does not need lab monitoring
• fewer drug interactions
• rapid onset

Question 8

Direct Xa inhibitors - cons/problems

Answer 8

No reversal agent

Metabolized by CYP450 - other medications can reduce the metabolism and cause bleeding

Question 9

Heparin action

Answer 9

Increases activity of AT III
Inhibition of:
- thrombin
- X
- VII, IX, XI, XII (with less efficiency)

Question 10

Unfractionated heparin

Answer 10

Natural, derived from pigs

High molecular weight, requires monitoring of aPPT

Question 11

LMWH

Answer 11

Dalteparin

Better bioavailability, 4x longer half life, does not require monitoring as it does not affect thrombin

Question 12

Heparin indications

Answer 12

Admin - IV or subcutanously

• short/immideate anticoagulation
• used in DVI, open heart surgery

Question 13

LMWH-like drug

Answer 13

Fondaperimax - inhibits factor IXa

• synthetic
• no glycosaminoglycan tail

Question 14

Glycosaminoglycan tail role in heparin

Answer 14

Responsible for thrombin inhibition

Question 15

Vitamin-K inhibitors mode of action

Answer 15

Warfarin

Inhibits epoxide reductase - necessary for recycling of vitamin K
Inhibits both intrinsic and extrinsic pathways, as well as common

Question 16

Vitamin-K inhibitors - lab test

Answer 16

Prothrombin time/INR
normal - 1
warfarin goal - 2-3

Requires regular monitoring

Question 17

Vitamin-K inhibitors indications

Answer 17

Clot disorders

• DVT
• AFIB
• MI, prosthetic heart valves

Question 18

Vitamin-K inhibitors half life

Answer 18

around 40 hours

Question 19

Vitamin-K inhibitors SE/contraindications

Answer 19

CYP450 metabolized
Can cross placenta
Warfarin induced skin necrosis
Initial coagulatory state has to be bridged with heparin