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EXERPT FROM: Clinical Pharmacy Anticoagulation and Anemia Service (CPAAS) Guidelines & Protocols
Kaiser Permanente Colorado
INITIATION OF ANTICOAGULATION THERAPY
Prior to initiating anticoagulation therapy, an appropriate diagnosis should be objectively confirmed. In
the absence of an objectively confirmed diagnosis, the referring physician should consult with their
Regional Department Chief or the CPAAS physician liaison prior to initiating anticoagulation therapy.
The referring physician should determine the appropriateness of ongoing anticoagulation therapy for
each patient. However, CPAAS staff should agree on the appropriateness of therapy prior to patient
enrollment in the service.
The CPAAS pharmacist should assess the patient’s current medical, drug, dietary and lifestyle history;
level of understanding and literacy; health beliefs and attitudes; motivation for self-care behavior; and
other environmental or behavioral barriers to learning and adherence when therapy is instituted.
Concerns regarding the appropriateness of anticoagulation therapy should be discussed with the
referring physician.
The therapeutic range (INR, aPTT, or anti-factor Xa level) for each patient should be determined by the
referring physician in consultation with CPAAS pharmacists. Considerations in determining the
therapeutic range should include assessment of the indication for therapy, as well as patient-specific
risks and benefits. Therapeutic ranges should be evidence based. INR target ranges of less than one INR
unit should be avoided (e.g. 2.0 to 2.5).
The initial daily dose of warfarin for most adult patients should be 5 mg. Smaller initial daily doses (e.g.
<5 mg) might be appropriate for patients with potential for increased warfarin sensitivity.
Pharmacogenetic testing should not be routinely used to determine initial warfarin doses.
Following initiation of warfarin therapy, an INR should be checked after 2 to 3 days and every 2 to 7 days
thereafter until the dose of warfarin stabilizes. More frequent monitoring may be necessary for patients
being treated concurrently with injectable anticoagulants as well as those with an unexpected response
to therapy, medical instability or within two weeks of heart valve replacement surgery. During initial
titration, warfarin dosage increases should not exceed doubling of the previous total weekly (or total
daily) dose. Omitting warfarin doses may be necessary in the setting of excessive INR response.
Upon enrollment into CPAAS a note should be placed into HealthConnect in the problem list under the
diagnosis of anticoagulant therapy or oral anticoagulant, not warfarin, long term therapy indicating that
the patient is active with the service. The patient will be entered into the DawnAC database.