MERCY MEDICAL CENTER – SIOUX CITY
INPATIENT ANTICOAGULATION MANAGEMENT
8401.0340
Developed by: Department of Pharmacy
Date: 09/08
Approved by: Director of Pharmacy
Date: 10/08
Scope:
Pharmacy
Reviewed/Revised: Jan 2009, May 2009, Aug 2010
I.
PURPOSE:
The goal of the anticoagulation service is to provide continuity of care to patients who require
anticoagulation; enhance patient care through education, monitoring and close follow-up; and reduce
adverse events associated with anticoagulation therapy.
II.
POLICY:
The department of pharmacy is responsible for the management of warfarin for patients under he
order of a prescriber. The pharmacist will order necessary lab work and dosing per protocol.
The department of pharmacy will be responsible for providing warfarin education for all patients.
III.
EQUIPMENT:
Cerner Pharmacy Computer System (PharmNet (Med Manager) and PowerChart)
IV.
PATIENT TEACHING:
N/A
When warfarin is initiated, patients will be given the Introduction to Anticoagulation handout.
During their hospital stay they will be given the opportunity to watch the “Coumadin and You”
DVD. Prior to discharge, a pharmacist will provide the Patient Information Pamphlet, verbal
counseling on warfarin, and answer questions from the patient and/or caregivers. Provision of
education will be documented in the patient’s electronic medical record. Nursing will document all
education provided in the anticoagulation section of the patient education form. Pharmacists will
document education provided as a pharmacy clinical intervention.
V.
PROCEDURE:
All patients on warfarin must have a baseline INR before a dose of warfarin is received. A
baseline INR is defined as an INR done within the last 72 hours. Pharmacists will verify a
baseline INR has been completed before the initial warfarin dose is verified. If a baseline INR is
not ordered by the physician the pharmacist shall order an INR per protocol. If a baseline INR
was obtained an outside facility, the result will be recorded in PowerChart.
Initiating a request for Pharmacist management of warfarin therapy per pharmacy
protocol
The physician must write or give a verbal order or enter an electronic order for “pharmacy to
Dose Warfarin”. The order shall also include the desired target INR, the indication for warfarin,
and the duration of anticoagulation. If this information is not given, dosing will be based of
CHEST guidelines. This order will allow pharmacists to order warfarin and necessary lab work.
MERCY MEDICAL CENTER – SIOUX CITY
INPATIENT WARFARIN DOSING
Initiation of Therapy
Physicians may request pharmacists to dose warfarin (Coumadin®) according to this protocol,
stating in their order the indication for warfarin and the target International Normalized Ratio
(INR). Upon receiving such an order, a pharmacist will review the patient’s chart for conditions
affecting warfarin sensitivity, coagulation labs, potential drug interactions with warfarin and
other medical information pertinent to warfarin dosing. The pharmacist will document in the
anticoagulation dosing form and complete a clinical pharmacy intervention daily. All warfarin
doses will be administered at 1600. When requests for Pharmacy to Dose Warfarin are received
after 1600, the pharmacist will begin dosing of warfarin the next day.
Unless otherwise specified by the physician, the targeted INRs used to guide warfarin therapy
will be those recommended by the most recent American College of Chest Physicians (ACCP)
Consensus Conference on Antithrombotic Therapy (1). Targeted INRs are:
Indication
INR
Prophylaxis of venous thrombosis (other than highrisk surgery)
2.0 – 3.0
Treatment of Deep Vein Thrombosis/Pulmonary
Embolism
2.0 – 3.0
Prevention of systemic embolism
2.0 – 3.0
Tissue heart valves
Acute Myocardial Infarction (to prevent systemic
embolism)
2.0 – 3.0
AMI (to prevent recurrent MI)
2.5 – 3.5
Valvular heart disease
2.0 – 3.0
Atrial Fibrillation
2.0 – 3.0
Bileaflet mechanical valve in aortic position
2.0 – 3.0
Mechanical prosthetic valves (high risk)
2.5 – 3.5
Presence of Lupus Anticoagulant or Antiphospholipid
Antibodies
2.5 – 3.5
Guidelines for Selecting Initial Warfarin Doses
If a patient is admitted on a maintenance dose of warfarin, check the INR. If the INR is
therapeutic, continue that maintenance dose.
Otherwise, the initial starting doses of warfarin will be those listed in the following table.
***Pharmacists may select a lower or higher starting dose of warfarin as the patient’s condition or
medical history warrants.
Patient Condition
Suggested Daily Warfarin Dose
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MERCY MEDICAL CENTER – SIOUX CITY
INPATIENT WARFARIN DOSING
Previously on warfarin
Continue previous regimen if INR is in
target range
69 years or younger
5 mg
DVT prophylaxis following joint
replacement
5 mg
70 years old or older
4 mg
Impaired nutritional status
4 mg
Acute or exacerbation of congestive heart
failure
4 mg
High risk of bleeding
4 mg or less
Selecting a Warfarin maintenance dose
For patients 70 years of age or older, give a fixed initial dose for the first two days of warfarin
therapy and then obtain an INR the next morning to guide the selection of a maintenance dose as
outlined in the following table.
Suggested algorithm for selecting a warfarin maintenance dose in inpatients 70 years old
and older when the target INR is 2.0 to 3.0
If day 3 INR result
is:
Suggested maintenance dose is:
Less than 1.3
5 mg
1.3 to 1.4
4 mg
1.5 to 1.6
3 mg
1.7 to 1.8
2 mg
1.9 to 2.4
1 mg
2.5 and higher
Measure INR daily and omit warfarin doses until INR is less
than or equal to 2.4
Adapted from Siguret V, Gouin I, Debray M, et al. Initiation of warfarin therapy in elderly
medical inpatients: a safe and accurate regimen. Amer J Med 2005;118:137-42.
For patients younger than 70 years old, the following table may be used to guide dosing
Day of Warfarin
therapy
Day 3
INR Value
Dose of Warfarin to give
< 1.5
1.5 – 1.9
2.0 – 2.5
2.6 – 3.0
> 3.0
Between 5 and 7.5 mg
2.5 – 5 mg
0 – 2.5 mg
0 – 2 mg
No dose
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MERCY MEDICAL CENTER – SIOUX CITY
INPATIENT WARFARIN DOSING
Day 4
< 1.5
1.5 – 1.9
2.0 – 3.0
> 3.0
10 mg
5 – 7.5mg
0 – 5 mg
No dose
Day 5
< 1.5
1.5 – 1.9
2.0 – 3.0
> 3.0
10 mg
7.5 – 10 mg
0 – 5 mg
No dose
Day 6
< 1.5
1.5 – 1.9
2.0 – 3.0
> 3.0
7.5 - 12.5 mg
5 - 10 mg
0 - 5mg
No dose
Management of Elevated INRs
Post-operative patients (including orthopedic surgery patients) – The following guidelines will be
used when recommending to physicians the dose of vitamin K needed to reverse excessive
anticoagulation.
Warfarin Reversal Guidelines (Adapted from 8th ACCP Consensus Conference on Antithrombotic
Therapy)
SIGNIFICANT
INR LEVEL
RECOMMENDATION
BLEEDING
>TR BUT <5
NO
•Lower the dose OR
•Omit a dose and resume at a lower dose when
in TR – monitor more frequently OR
•If only slightly elevated, do nothing
>5 BUT <9
NO
•Omit the next 1-2 doses, monitor frequently,
and resume at appropriate adjusted dose when
in TR OR
•Omit a dose and administer 1-2.5mg of
vitamin K* orally OR
•If rapid reduction, administer less than or
equal to 5mg of vitamin K orally - Can give 12mg of vitamin K orally if needed
>9
NO
•Hold warfarin - administer vitamin K 2.5-5mg
orally, monitor INR frequently, re-administer
vitamin K as necessary. May resume warfarin
at a lower dose once INR is in TR
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MERCY MEDICAL CENTER – SIOUX CITY
INPATIENT WARFARIN DOSING
ANY
YES
•Hold warfarin - administer vitamin K 10mg
slow IV infusion supplemented with: fresh
frozen plasma, prothrombin complex
concentrate, or recombinant factor VII. Repeat
vitamin K every 12 hours as needed
ANY
LIFETHREATENING
(ex. Increased
ICP)
•Hold warfarin - administer fresh frozen
plasma, prothrombin complex concentrate, or
recombinant factor VII and give vitamin K
10mg by slow IV infusion - Repeat as
indicated by INR value
TR = Therapeutic Range
* Only 5mg scored tablets commercially available (2.5mg is possible but other strengths are
not)
If Pharmacy to Dose Warfarin order is discontinued for any reason the patient is no longer a
warfarin protocol patient. The physician must re-order the Pharmacy to Dose Warfarin per
protocol if she/he wants warfarin managed per pharmacy protocol.
If warfarin is discontinued and re-started using the warfarin protocol, the pharmacist may restart
on the previous dose of warfarin if the INR was in the desired therapeutic range prior to being
discontinued.
If a patient requires an invasive procedure that necessitates warfarin being held or anticoagulation
reversal, the patient will no longer be treated using the protocol.
Management of Warfarin During Invasive Procedures
For emergent invasive procedures, vitamin K can be used to reverse effects of warfarin (see
above). The following recommendations are from ACCP1:
Risk of thromboembolism
Recommended procedure
Low risk (no thromboembolism for
> 3 months, atrial fibrillation
patients without a history of stroke
or other risk factors, and bileaflet
mechanical cardiac valve in aortic
position)
Stop warfarin approximately 4 days before surgery, allow INR
to return to near-normal level, briefly administer post-op
prophylaxis (if the intervention itself creates a higher risk of
thrombosis) using heparin 5,000 units subcutaneously or a
prophylactic dose of enoxaparin and simultaneously begin
warfarin therapy; alternatively, a low dose of unfractionated
heparin (UFH) or a prophylactic dose of low molecular weight
heparin (LMWH) can also be used preoperatively.
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MERCY MEDICAL CENTER – SIOUX CITY
INPATIENT WARFARIN DOSING
Intermediate risk of
thromboembolism
Stop warfarin approximately 4 days before surgery, allow the
INR to fall, cover the patient with heparin 5,000 units
subcutaneously beginning 2 days before surgery or with a
prophylactic dose of LMWH, and then commence low-dose
heparin (or LMWH) and warfarin postoperatively; some
individuals would recommend a higher dose of heparin or a full
dose of LMWH in this setting
High risk of thromboembolism
Stop warfarin therapy approximately 4 days before surgery,
allow INR to return to normal, begin therapy with full-dose
heparin or full-dose LMWH as the INR falls (approx 2 days
before surgery). heparin infusion should be discontinued 5
hours before surgery with the expectation that the anticoagulant
effect will have worn off at the time of surgery; it is also
possible to continue with subcutaneous heparin or LMWH and
to stop 12-24 hours before surgery with the expectation that the
anticoagulant effect will be very low or have worn off at the
time of surgery
(Patients with recent [< 3 months]
history of DVT, or mechanical
cardiac valve in the mitral position
or an old model of cardiac valve
[ball/cage])
Low risk of bleeding
Continue warfarin therapy at a lower dose and operate at an INR
or 1.3 to 1.5, an intensity that has been shown to be safe in
gynecologic and orthopedic surgical patients; the dose of
warfarin can be lowered 4 or 5 days before surgery; warfarin
therapy can then be restarted postoperatively, supplemented
with a low dose of UFH (5000 units subcutaneously) or a
prophylactic dose of LMWH (enoxaparin) if necessary
Adapted from Table 8 in: the Seventh ACCP Conference on Antithrombotic and Thrombolytic
Therapy. Chest 2004 (suppl) 126:214S-215S.
Management of enoxaparin (Lovenox ®), fondaparinux (Arixtra ®) or unfractionated Heparin
(UFH) when used
in combination with Warfarin.
It is commonplace to use either unfractionated heparin (UFH) or a low molecular weight heparin
(LMWH) (e.g. enoxaparin (Lovenox ®), in combination with warfarin in order to provide an
immediate anticoagulant effect until the warfarin regimen reaches a target therapeutic INR. This
protocol authorizes the pharmacist to discontinue any concurrent UFH or LMWH once the INR
has been in the desired target range for two consecutive days and the patient has received at least
five total days of heparin or LMWH therapy and heparin or LMWH will not be discontinued
before three days of bridge therapy.
Frequency of INR Monitoring
INRs will be obtained daily. Once the INR is in the desired target range for two or more
consecutive days, the frequency of INR monitoring may be reduced.
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MERCY MEDICAL CENTER – SIOUX CITY
INPATIENT WARFARIN DOSING
Discharge
An appointment for a follow-up INR should be made prior to discharge and communicated to the
patient. Information regarding the doses the warfarin received will be sent to the provider that
will be managing anticoagulation the patient after discharge.
VI.
PHARMACEUTICAL WASTE MANAGEMENT:
Warfarin is a P-Listed Pharmaceutical Waste (acutely hazardous waste) and will be identified with a
black sticker with a white ”P”. Unused warfarin tablets and the packaging will be wasted to the
Black ‘P’ container. The containers and packaging that hold acutely hazardous pharmaceuticals must
be collected as hazardous waste.
VII.
DOCUMENTATION:
When pharmacy is dosing warfarin the pharmacist will complete a clinical pharmacy intervention
daily. The initial day of warfarin therapy the pharmacist will compete the warfarin dosing by Rx
intervention. Each day after the initial day, the pharmacist will complete a follow up warfarin
intervention form.
VIII.
DEFINITIONS:
IX.
REFERENCES:
N/A
Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004 (suppl)
126:214S-215S.
Siguret V, Gouin I, Debray M, et al. Initiation of warfarin therapy in elderly medical inpatients:
a safe and accurate regimen. Amer J Med 2005;118:137-42.
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