warfarin

Adult Dosing .

Dosage forms:  TAB: 1 mg, 2 mg, 2.5 mg, 3 mg, 4 mg, 5 mg, 6 mg, 7.5 mg, 10 mg

Special Note

[tx conversion]

Info: to convert from LMWH/UFH, overlap tx at least 5 days, then D/C LMWH/UFH once target INR x24h; to convert from apixaban or rivaroxaban, D/C other anticoagulant, start warfarin w/ parenteral anticoagulant at next scheduled dose; to convert from dabigatran, overlap tx x3 days if CrCl >50, x2 days if CrCl 30-50, or x1 day if CrCl 15-30; refer to ACCP and ACC/AHA guidelines or institution protocols

[tx interruption]

Info: depending on bleeding risk and target INR, consider holding tx around 5 days before surgery or invasive procedure; resume tx w/in 24h postop; bridge w/ parenteral anticoagulant in pts w/ high VTE risk; refer to ACCP and ACC/AHA guidelines or institution protocols

DVT/PE tx

[individualize dose PO qd x3mo]

Start: 2-5 mg PO qd on day 1-2 of parenteral anticoagulant; Info: target INR 2-3; consider lower start dose if elderly, debilitated, warfarin-sensitive genotype, or other risk factors; consider longer tx if DVT/PE unprovoked; refer to ACCP and ACC/AHA guidelines or institution protocols

DVT/PE prophylaxis, postpartum

[individualize dose PO qd x6wk]

Start: 2-5 mg PO qd; Info: for women w/ prior VTE; target INR 2-3; consider lower start dose if debilitated, warfarin-sensitive genotype, or other risk factors; refer to ACCP and ACC/AHA guidelines or institution protocols

thromboembolism/stroke prevention

[non-valvular atrial fibrillation]

Dose: individualize dose PO qd; Start: 2-5 mg PO qd; Info: for pts w/o moderate-severe mitral stenosis or mechanical heart valve; target INR 2-3; consider starting 10 mg PO qd x2 days in healthy outpatients; consider lower start dose if elderly, debilitated, warfarin-sensitive genotype, or other risk factors; refer to ACCP and ACC/AHA guidelines or institution protocols

[valvular atrial fibrillation]

Dose: individualize dose PO qd; Start: 2-5 mg PO qd; Info: for pts w/ moderate-severe mitral stenosis or mechanical heart valve; target INR 2-3 if mechanical aortic or bioprosthetic mitral valve; target INR 2.5-3.5 if caged ball, caged disk, mechanical mitral or mitral/aortic valve; consider starting 10 mg PO qd x2 days in healthy outpatients; consider lower start dose if elderly, debilitated, warfarin-sensitive genotype, or other risk factors; refer to ACCP and ACC/AHA guidelines or institution protocols

LV thrombus

[anterior MI-associated]

Dose: individualize dose PO qd x3-6mo; Info: for pts undergoing bare-metal, drug-eluting, or no stenting; target INR 2-3; use w/ antiplatelet tx; refer to ACCP and ACC/AHA guidelines or institution protocols

[systolic LV dysfxn-associated]

Dose: individualize dose PO qd x3mo; Info: for pts w/o established CAD; Info: target INR 2-3; refer to ACCP and ACC/AHA guidelines or institution protocols

VTE prophylaxis, cardioversion (off-label)

[individualize dose PO qd]

Start: 2-5 mg PO qd at least 3wk before cardioversion; Info: for pts w/ afib/flutter duration >48h or unknown; target INR 2-3; consider starting w/ 10 mg PO qd x2 days in healthy outpatients; consider lower start dose if elderly, debilitated, warfarin-sensitive genotype, or other risk factors; continue tx for at least 4wk after procedure; refer to ACCP and ACC/AHA guidelines or institution protocols

VTE prophylaxis, orthopedic surgery (off-label)

[individualize dose PO qd x10-14 days]

Start: 2-5 mg PO qd; Info: target INR 2-3; consider lower start dose if elderly, debilitated, warfarin-sensitive genotype, or other risk factors; consider tx up to 35 days if major surgery; refer to ACCP and ACC/AHA guidelines or institution protocols

ischemic stroke (off-label)

[individualize dose PO qd x3-6mo]

Start: 2-5 mg PO qd; Info: for pts w/ cerebral venous sinus thrombosis; target INR 2-3; consider starting w/ 10 mg PO qd x2 days in healthy outpatients; consider lower start dose if elderly, debilitated, warfarin-sensitive genotype, or other risk factors; refer to ACCP and ACC/AHA guidelines or institution protocols

renal dosing

[no adjustment]

renal impairment: no adjustment

HD/PD: no adjustment; no supplement

hepatic dosing

[see below]

hepatic impairment: consider decr. usual dose

Peds Dosing .

Dosage forms:  TAB: 1 mg, 2 mg, 2.5 mg, 3 mg, 4 mg, 5 mg, 6 mg, 7.5 mg, 10 mg

anticoagulation (off-label)

[infants/children]

Dose: 0.05-0.34 mg/kg/dose PO qd; Start: 0.1-0.2 mg/kg/dose PO qd x2 days; Max: 10 mg/dose; Info: adjust dose based on INR; duration, target INR varies w/ indication, pt population, bleeding risk factors; consider lower start dose if debilitated, warfarin-sensitive genotype, or other risk factors; to convert from LMWH/UFH, overlap tx at least 5 days, then D/C LMWH/UFH once target INR x24h; to convert from rivaroxaban, overlap tx x2 days; to convert from dabigatran, overlap tx x3 days; refer to ACCP guidelines or institution protocols

renal dosing

[no adjustment]

renal impairment: no adjustment

HD/PD: no adjustment; no supplement

hepatic dosing

[see below]

hepatic impairment: consider decr. usual dose