Anticoagulants - Direct thrombin inhibitors

Question 1

Direct thrombin inhibitors - groups/drugs and adm

Answer 1

Hirudin derivatives - parenterally (IV)

Dabigatran - orally

Question 2

Hirudin derivatives

Answer 2

Hirudin
Lepirudin
Bivalirudin
Argatroban

Question 3

Hirdurin derivatives - adverse effects

Answer 3

Bleeding

Do not cause thrombocytopenia

Question 4

Lepirudin - indications

Answer 4

Replace heparin after HIT.

Question 5

Hirudin derivatives - indiactions

Answer 5

Prevent thrombosis in unstable angina, acute MI, stent insertions and coronary angioplasty.

Question 6

Argatroban - indications

Answer 6

Prophylaxis and treatment of thrombosis in pts with HIT.

Pts undergoing percutaneous coronary interventions for MI.

Question 7

Dabigatran - interactions

Answer 7

Few interactions with drugs and food.
Renal impairment decreases elimination (reduce dose).
The drug (bot not the active metabolite) is a substrate for P-glycoprotein (Pgp) transporter --> contraindicated with rifampin (inducer of Pgp transporter.

Question 8

Dabigatran - MOA

Answer 8

Potent, competitive and reversible inhibition of thrombin.

Question 9

How can the effect of dabigatran be monitored?

Answer 9

Thrombin clotting time (TT). However, monitoring is not usually necessary.

Question 10

Dabigatran - indications

Answer 10

Nonvalvular atrial fibrillation (reduce risk of stroke and embolism).
Hip/knee replacements - prevent thromotic complications.

Question 11

Dabigatran - adverse effects

Answer 11

Bleeding.

Dyspepsia, gastritis-like symptoms (reduced with food or H2 blocker).

Question 12

Hemorrhage associated with dabigatran - treatment

Answer 12

There is no antidote. Give plasma or RBCs.

Question 13

Active factor X inhibitors - 2 drugs

Answer 13

Apixaban

Rivaroxaban

Question 14

Rivaroxaban - indications

Answer 14

Hip/knee replacement: prevent DVT, blood clots, pulmonary embolism

Question 15

Rivaroxaban - interactions

Answer 15

Metabolized by P450 isoenzymes (esp 3A4).

Increased levels bu Pgp transporter inhibitor.

Question 16

Rivaroxaban - adverse effects

Answer 16

Bleeding

Careful in pregnancy.

Question 17

Apixaban - indications

Answer 17

Atrial fibrillation when warfarin cannot be used.

Prevent venous thromboembolism and cardiovascular events in MI.

Question 18

Rivaroxaban, Apixaban, Endoxaban - antidote

Answer 18

Andexanet alfa (AndexXa). Dosing for the initial bolus and subsequent infusion depend on the dose level of the factor Xa inhibitor and the interval since it was last taken.

-OR-

4-factor PCC (Kcentra, Beriplex P/N, Octaplex). Dosing can be done with a fixed dose of 2000 units OR a weight-based dose of 25 to 50 units per kg.

Active factor VII

Question 19

Dabigatran(Pradaxa) reversal agent

Answer 19

Idarucizumab (Praxbind). Dose: 5 grams*