VTE Doses for Anticoagulants

Question 1

low molecular weight heparin

Answer 1

1mg/kg q 12 h sq (can rarely be given IV)

may need to adjust doses with BMI of 40 kg/m2 or more

Question 2

initial outpatient dose of warfarin

Answer 2

1. 5 mg daily for 3 days
2. 2.5 mg daily for 3 days for sensitive patients
3. (check INR the morning of day 4)

higher body weights may require higher doses and CYP2C9

Question 3

warfarin dose for INR < 1.5

Answer 3

1. 7.5 to 10 mg daily for 2-3 days
2. 5-7.5 mg daily for 2-3 days for sensitive patients

Question 4

warfarin dose for INR 1.5-1.9

Answer 4

1. 5 mg daily for 2-3 days
2. 2.5 mg daily for 2-3 days for sensitive patients

Question 5

warfarin dose for INR 2 to 3

Answer 5

1. 2.5 mg daily for 2-3 days
2. 1.25 mg daily for 2-3 days for sensitive patients

Question 6

warfarin dose for INR 3.1 to 4

Answer 6

1. 1.25 mg daily for 2-3 days
2. 0.5 mg daily for 2-3 days for sensitive patients

Question 7

warfarin dose for INR >4

Answer 7

hold doses until INR < 3

Question 8

warfarin limitations

Answer 8

1. frequent INR monitoring
2. bridging requirements
3. peri-procedural anticoagulation
4. drug-drug interactions
5. drug-food interactions

Question 9

maintenance adjustment of warfarin for subtherapeutic INR <1.5

Answer 9

1. increase weekly maintenance dose by 10% to 20%
2. consider a one-time supplemental dose 1.5-2 times the daily dose

Question 10

maintenance adjustment of warfarin for subtherapeutic INR 1.5 to 1.7

Answer 10

1. increase weekly maintenance dose by 5%-15%
2. consider a one time supplemental dose 1.5 to 2 times the daily dose

Question 11

maintenance adjustment of warfarin for subtherapeutic INR 1.8-1.9

Answer 11

1. no dosage adjustment may be necessary if the last 2 INR were in range
2. if adjustment needed, increase weekly maintenance dose by 5% to 10%
3. consider a one time supplemental dose: 1.5-2 times daily dose

Question 12

if the factor causing subtherapeutic INR is transient

missed warfarin dose, temporary DDI

Answer 12

consider resumption of prior maintenance dose following a one-time supplemental dose

Question 13

maintenance adjustment of warfarin for supratherapeutic INR 3.1 to 3.2

Answer 13

1. no dosage adjustment may be necessary if the last INRs were in range
2. if dosage adjustment needed, decrease weekly maintenance dose by 5% to 10%

Question 14

maintenance adjustment of warfarin for supratherapeutic INR 3.3 to 3.4

Answer 14

decrease weekly maintenance dose by 5% to 10%

Question 15

maintenance adjustment of warfarin for subtherapeutic INR 3.5 to 3.9

Answer 15

1. consider holding 1 dose
2. decrease weekly maintenance dose by 5% to 15%

Question 16

maintenance adjustment of warfarin for supratherapeutic INR of 4-10 and no bleeding

Answer 16

1. hold until INR below upper limit of therapeutic range
2. decrease weekly maintenance dose by 5% to 20%
3. if patient considered to be at significant risk for bleeding, consider oral vitamin k

Question 17

maintenance adjustment of warfarin for supratherapeutic INR > 10 and no bleeding

Answer 17

1. hold until INR below upper limit of therapeutic range
2. administer vitamin k orally
3. decrease weekly maintenance dose by 5% to 20%

Question 18

if the factir causing supratherapeutic INR is transient

missed warfarin dose, temporary DDI

Answer 18

consider resumption of prior maintenance dose following a one-time held dose

Question 19

how to handle CYP2C9 mutations with warfarin

Answer 19

need to decrease patient dose requirements

Question 20

VKORC1 mutations reponse to warfarin

Answer 20

1. rare variant = need for high doses
2. common variant = lower dose requirements

Question 20

apixaban (eliquis) dosing

Answer 20

10 mg twice daily for 1 week, then 5 mg twice daily

okay in those > 120 kg or BMI > 40 kg/m2

Question 21

rivaroxaban (xarelto) dosing

Answer 21

15 mg twice daily for 21 days then 20 mg daily

Okay in those > 120 kg or BMI ≥ 40 kg/m
Avoid use CCl < 15 mL/min
Doses > 10 mg should be given with food

Question 22

edoxaban (savaysa) dosing

Answer 22

1. after 5 days parenteral: > 60 kg – 60 mg daily; ≤ 60 kg: 30 mg daily
2. CrCl 15-50ml/min: 30 mg daily

Question 23

fondaparinux (arixtra) dosing

Answer 23

1. avoid use CrCl < 30 ml/min
2. avoid weight < 50 kg

Question 24

dabigatran (pradaxa) dosing

Answer 24

1. after 5 days parenteral then 150 mg twice daily
2. avoid use CrCl < 30 mL/min
3. poor outcomes in those > 120 kg or BMI ≥ 40 kg/m2