0071643192.pdf

HEMATOLOGY, ONCOLOGY, ALLERGY,

AND IMMUNOLOGY

CONTRAINDICATIONS

■ Hypersensitivity, active GI bleeding, intracranial hemorrhage, current bac-
terial endocarditis, heparin-induced thrombocytopenia (HIT)

DOSING

■ Bolus 70–80 units/kg IV followed by infusion 15–18 units/kg/hour

MONITORING

■ Follow aPTT and titrate based on therapeutic range (usually 1.5–2.5 ×the
normal value).

COMPLICATIONS

■ Major bleeding
■ HIT syndrome (autoimmune response to heparin →low platelets, thrombosis)

REVERSAL

■ Stop heparin—short half-life
■ Protamine sulfate, 1 mg IV for every 100 units of heparin, over the previous
four hours to a maximum of 50 mg

Low-Molecular-Weight Heparin

Inhibits activity of factor Xa; includes enoxaparin, dalteparin, ardeparin

TABLE 9.10. Medications Affecting INR

INCREASEINR DECREASEINR

Allopurinol, amiodarone, azithromycin, cimetidine, Carbamazepine, cholestyramine,

clotrimazole, fluroquinolones, INH, metronidazole, dicloxacillin, griseofulvin, haloperidol,

omeprazole, penicillin, phenytoin, prednisone, nafcillin, ranitidine, rifampin

propoxyphene, quinidine, statins, sulfonyureas,

tetracycline, tamoxifen, zafirlukast

TABLE 9.11. Warfarin Reversal

INR BLEEDING TREATMENT

< 5 No Hold dose, recheck INR in 24 hours

5—9 No Hold dose, consider oral vitamin K 1—2 mg PO, recheck

INR in 24 hours

> 9 No Hold dose, vitamin K 2—4 mg PO, recheck INR in 24 hours

Any elevation Major bleeding Hold dose, FFP transfusion or factor concentrates, vitamin

K 5—10 mg slow IV or sub Q

Any elevation Minor bleeding Hold dose, vitamin K 2—4 mg PO

HIT syndrome is less common

with low-molecular-weight

heparin (LMWH) than with

heparin. In patients with HIT,

stop the heparin or LMWH

and start a direct thrombin

inhibitor.