0071643192.pdf

TOXICOLOGY

SYMPTOMS/EXAM

■ Bleeding—may be spontaneous or related to trauma

DIFFERENTIAL

■ Other “warfarin-like” anticoagulants, heparin/LMWH, ingestion of brodi-

facoum (rat poison).

DIAGNOSIS

■ Usually clear from patient’s history and exam.

■ PT and INR should be monitored periodically for 3–4 days.

TREATMENT

■ Supportive therapy, including PRBC transfusion as needed

■ Activated charcoal—if within 1–2 hours (with airway control as needed)

■ Oral cholestyraminemay enhance elimination.

■ Approach depends on INR level and presence of bleeding (see Table 6.9).

■ Vitamin K 1

■ Will reverse the blockade, but will not activate enough factors to reverse

coagulopathy for several hours

■ Can be given prophylactically for those patients not requiring anti-

coagulation

TABLE 6.9. Guidelines for Treatment of Overanticoaguation with Warfarin

CONDITION TREATMENT

INR < 5, no clinically significant Lower or skip dose.

bleeding Resume when INR therapeutic.

INR 5—9, no clinically significant Omit next one or two doses.

bleeding or

Skip dose and give vitamin K 1 (1—2mg PO).

Resume at lower dose when INR therapeutic.

INR > 9, no clinically significant Hold warfarin.

bleeding Give higher dose of vitamin K 1 (5—10 mg PO).

Resume at lower doses when INR therapeutic.

Serious bleeding at any Hold therapy.

elevation of INR Give vitamin K 1 (10 mg slow IV).

Give FFP or prothrombin complex concentrate (PCC).

Recombinant factor VIIa is an alterative therapy.

Life-threatening bleeding Hold warfarin.

Give FFP, PCC or recombinant factor VIIa.

Give vitamin K 1 (10 mg slow IV).

Repeat as necessary.

Onset of effect in overdose

is delayed and PT and

INR should be monitored

for 3—4 days.