Anticoagulants

Question 1

Heparin half life

Answer 1

1 hour

Question 2

Fondaparinux

Answer 2

AT-binding synthetic pentasaccharide that is a factor Xa inhibitor; does not generally require monitoring but can check a Factor Xa level

Administered as subq injxn; can be used for clinically stable HIT

Contraindicated w/ CrCl <30; caution with 30-50

**No reversal agent

Question 3

HIT Type 1

Answer 3

Negatively charged heparin molecules adhere to platelets, clump, and then are cleared by the spleen

Plt count usually not <100,000; occurs in first 2-3 days of heparin exposure

Question 4

HIT Type II

Answer 4

Thrombohemorrhagic complications; calculate 4T score and start argatroban, check LE doppler US

Question 5

Argatroban

Answer 5

DTI w/ half life of 40-50 minutes and is hepatically cleared

-aPTT typically increases to 1.5-3x baseline

***Caution with altered hepatic fnxn, HF, post cardiac surgery

Question 6

Bivalirudin

Answer 6

DTI w/ half life of 25mins used w/ unstable angina undergoing PCI w/ +/- GPIIb/IIIa inhibitor (HIT use is off label)

-Needs adjustment for renal or liver dysfunction

Question 7

Anticoagulation with APS

Answer 7

Use warfarin per TRAPS trial (was stopped early due to observed benefit; they compared Xarelto w/ warfarin)

Question 8

What enzyme does warfarin inhibit?

Answer 8

Vitamin K reductase

Question 9

What conditions is warfarin currently preferred in?

Answer 9

APS
Mechanical heart valve
Severe renal impairment/hemodialysis
? Extremes of weight
Drug interactions/contraindication to DOAC

Question 10

How long should heparin bridge take?

Answer 10

At least 5 days and until INR >2 in patient w/ acute block

Question 11

DOAC to take with food

Answer 11

Xarelto; increases bioavailability

Question 12

DOAC that is (less) renally excreted

Answer 12

Eliquis (27%)

Question 13

Reversal agent for DOACs

Answer 13

Andexanet

Question 14

Reversal agent for dabigatran

Answer 14

Idraucizumab