Protocol :Coumadin Therapy Protocol

Effective Date: 01/30/01

Review Date: 11/28/07

PROTOCOL :COUMADIN THERAPY PROTOCOL

SUMMARY: To provide a standardized guideline for indications, dosing, and monitoring of patients on Coumadin therapy. This will also provide a guideline for adjustment of Coumadin, based on the INR (International Normalized Ratio) value.

DESCRIPTION:

1.Coumadin (or Warfarin) is a medication used to increase the Protime in patients with risk factors for blood clots. Current dosing allows for adjustments of 0.5 mg, which allows for most patients to be on a uniform strength of Coumadin daily.

2.Current therapeutic goals for anticoagulation are as follows

A.Treatment of DVT (Deep Vein Thrombosis) 1st episode INR 2-3. Treat for 3-6 months.

1.)Patient at high risk for reoccurrence should be treated lifelong.

2.)Patient with antiphospholipid antibody, INR 3-4 treat lifelong.

B.Treatment of PE (Pulmonary Embolism) 1st episode INR 2-3. Treat for 3-6 months.

1.)Patient at high risk for reoccurrence should be treated lifelong.

2.)Treatment of Tissue heart valves INR 2-3. Treat for 3 months.

3.)Treatment of Prosthetic heart valves

a.)Aortic/Mitral mechanical INR 2.5-3.5, lifelong.

b.)Aortic/Mitral bioprosthetic INR 2-3 for 3 months.

c.)Treatment of Atrial fibrillation INR 2-3, lifelong (as indicated).

3.Monitoring of Coumadin therapy

A.SCHC uses a Coaguchek to monitor INR values for patients.

B.Frequency of testing depends on the patient and the reason for anticoagulation.

1.)For most patients starting out, weekly monitoring is recommended until their INR has stabilized in the therapeutic range. (More frequent monitoring is advised if the patient needs to reach a therapeutic level in a short period of time.)

2.)Once a patient is stabilized, monthly monitoring is recommended.

3.)After any dose adjustment with Coumadin, the patient should be rechecked in 1 week or less. See Table 1 for dosing adjustment recommendations.

Table 1*

4.Drug interactions

A.Multiple medications are associated with interaction with warfarin. It is therefore necessary to monitor a patient’s INR closely when starting new medications. The following is a list of common medications that are known to increase or decrease the efficacy of warfarin:

1.)Increase INR: Amiodarone, Anti-fungal agents, Cefobid, Cefotan, Tagamet, Luvox, HMG CoA inhibitors, INH, Flagyl, NSAIDS, Paxil, Bactrim.

2.)Decreased INR: Penicillins, Anticonvulsants, and Barbiturates.

5.Treatment of patients with significantly elevated INR

A.If the patient is actively bleeding, give Vitamin K 10mg IM, FFP 15ml/kg, PCC 50U/kg and recheck INR in 6 hours. Repeat Vitamin K injections if INR > 4.0.

B.If the patient is not actively bleeding and INR<10, withhold Coumadin for 2-3 days and restart at lower dose, if indicated. You may give Vitamin K at 0.5-2.0 mg SC if rapid reversal is necessary.

C.If the patient is not actively bleeding and INR>10, give Vitamin K at 3mg SC and recheck INR in 6 hours.

*Table 1 reprinted from American Family Physician: Warfarin Therapy: Evolving Strategies in Anticoagulation, by Jon Horton, Pharm.D and Bruce Bushwick, MD February 1, 1999.

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