INRProtocol

Purpose:To optimize management of treatment of patients on chronic anticoagulation therapy with Warfarin and to reduce the time needed for physicians to review laboratory results, write orders and reschedule INR times. This protocol is not to be usedfor the initiation of Warfarin therapy.

Rationale:Warfarin is the medication most commonly prescribed as the primary means of preventing and treating thromboembolism. Warfarin inhibits Vitamin K participation in factor synthesis. After the first dose of Warfarin, approximately 5 days are required to achieve the desired antiembolic effect.

Indications:

INR between 2 to 3:Prophylaxis of venous thrombosis (high-risk surgery), treatment of venous thrombosis, treatment of PE, prevention of systemic embolism, tissue heart values, AMI (to prevent systemic embolism)*, valvular heart disease, atrial fibrillation

INR between 2.5 to 3.5Mechanical heart valves, antiphospholipid syndrome (Lupus anticoagulant), prevention of recurrent myocardial infarction (indicated in aspirin intolerant patient)

Physician Responsibilities:

  1. Initiate protocol by ordering INR Protocol.
  2. Determine INR range for the resident and indicate on Physician’s Order Sheet.
  3. Prescribe initial weekly dosage of Warfarin.
  4. Prescribe frequency of INR testing.

RN Responsibilities:

  1. Upon receipt of the admission INR results, the RN will use the Warfarin Dosage Table in the protocol to manage (in collaboration with the most responsible physician) the resident’s anti-coagulation therapy and INR monitoring.
  2. Obtain medical order to initiate INR Protocol. The medical order must include: dosage, route, drug frequency, INR range, and frequency of INR testing.
  3. Be aware of the drug interactions between Warfarin and many antibiotics. Consider having Warfarin dose reduced by 1/2to 1/3and/or increasing INR monitoring for duration of antibiotic therapy by receiving a medical order from the physician.
  4. Recognize signs of elevated INR and serious bleeding.
  5. Document all INR values and Warfarin changes on the INR Monitoring Record.
  6. Unless ordered otherwise, all Warfarin doses will be administered at 2000.

INR Protocol:

  1. Initial INR drawn upon admission.
  2. If INR within therapeutic range, maintain dose and check weekly on Monday.
  3. After INR is within therapeutic range for 4 consecutive weeks, reduce INR frequency to monthly unless more frequent monitoring is ordered by the physician.
  4. If INR is not in therapeutic range:
  5. Assess for a change in health, diet, medication adherence, lifestyle, bleeding, medications (ie. Was the medication held for a procedure? Was the resident prescribed antibiotics?).
  6. Follow Warfarin Dosage Algorithm or physician specific orders (which take precedence to the protocol). Repeat INR weekly (or more frequently as indicated or if ordered by the physician) until within therapeutic range.
  7. Adjust dose per the Warfarin dosage table to ordered INR target range. Each row on the dosage table represents an approximate 10% change in weekly dose from the row above and below.
  8. Avoid changing Warfarin dose more than once weekly unless ordered by physician.
  9. Consult with physician, nurse practitioner or pharmacist for clarification as needed.
  10. Hold Warfarin and notify physician on-call if resident actively bleeding.

INR Protocol

Warfarin Dosage Algorithm

INR Therapeutic Range 2.0 to 3.0
INR / Less than 1.5 / 1.5 to 1.9* / 2.0 to 3.0 / 3.0 to 3.9* / 4.0 to 4.9 / 5.0 to 5.9 / Greater than 5.9 (and no active bleeding)
Warfarin Dose Change / Obtain an order to give an additional dose and increase weekly dose by 20%within 24 hours. / Increase weekly dose by 10% / No change / Decrease weekly dose by 10% / Hold for 1 day. Obtain order to decrease weekly dose by 20% within 24 hours. / Obtain order tohold for 2 days and decrease weekly dose by 20% within 8 hours. / Obtain order for vitamin K 2-5mg po and hold until INR therapeuticwithin 8 hours.
Next INR / 7 days / 7 days / Per Protocol / 7 days / 7 days / 2-3 days / Next day or ASAP

* If INR is 1.8 to 2.0 or 3.0 to 3.2, consider no change and repeat INR in 7 days.

INR Therapeutic Range 2.5 to 3.5
INR / Less than 1.5 / 1.5 to 2.4* / 2.5 to 3.5 / 3.6 to 4.5* / 4.6 to 5.2 / 5.3 to 5.9 / Greater than 5.9
(and no active bleeding)
Warfarin Dose Change / Obtain an order to give an additional dose and increase weekly dose by 20% within 24 hours. / Increase weekly dose by 10% / No change / Decrease weekly dose by 10% / Hold for 1 day. Obtain order to decrease weekly dose by 20% within 24 hours. / Obtain order tohold for 2 days and decrease weekly dose by 20% within 8 hours. / Obtain order for vitamin K 2-5mg po and hold until INR therapeutic within 8 hours.
Next INR / 7 days / 7 days / Per protocol / 7 days / 7 days / 2-3 days / Next day or ASAP

* If INR is 2.3 to 2.4 or 3.6 to 3.7, consider no change and repeat INR in 7 days.

INR Protocol

Warfarin Dosage Table

Row / Weekly Dosage (in mg) / Sunday / Monday / Tuesday / Wednesday / Thursday / Friday / Saturday
A / 7 / 1 / 1 / 1 / 1 / 1 / 1 / 1
B / 8 / 1 / 2 / 1 / 1 / 1 / 1 / 1
C / 9 / 1 / 2 / 1 / 1 / 1 / 2 / 1
D / 10 / 1 / 2 / 1 / 2 / 1 / 2 / 1
E / 11 / 2 / 1 / 2 / 1 / 2 / 1 / 2
F / 12 / 2 / 1 / 2 / 2 / 2 / 1 / 2
G / 14 / 2 / 2 / 2 / 2 / 2 / 2 / 2
H / 15 / 2 / 3 / 2 / 2 / 2 / 2 / 2
I / 16 / 2 / 3 / 2 / 2 / 2 / 3 / 2
J / 18 / 3 / 2 / 3 / 2 / 3 / 2 / 3
K / 20 / 3 / 2 / 3 / 3 / 3 / 3 / 3
L / 22 / 3 / 4 / 3 / 3 / 3 / 3 / 3
M / 24 / 3 / 4 / 3 / 4 / 3 / 4 / 3
N / 26 / 4 / 3 / 4 / 4 / 4 / 3 / 4
O / 29 / 4 / 5 / 4 / 4 / 4 / 4 / 4
P / 32 / 5 / 4 / 5 / 4 / 5 / 4 / 5
Q / 35 / 5 / 5 / 5 / 5 / 5 / 5 / 5
R / 38 / 5 / 6 / 5 / 6 / 5 / 6 / 5
S / 42 / 6 / 6 / 6 / 6 / 6 / 6 / 6
T / 46 / 7 / 6 / 7 / 6 / 7 / 6 / 7
U / 51 / 7 / 8 / 7 / 7 / 7 / 8 / 7
V / 56 / 8 / 8 / 8 / 8 / 8 / 8 / 8
W / 62 / 9 / 8 / 9 / 9 / 9 / 9 / 9
X / 68 / 10 / 9 / 10 / 10 / 10 / 9 / 10
Y / 75 / 11 / 10 / 11 / 11 / 11 / 10 / 11

* Each row represents an approximate 10% weekly dose change from the row above or below.

Example 1: 80 year old female with atrial fibrillation prescribed anticoagulation with Warfarin indefinitely. Her INR values have been stable for many months at rowH of the protocol. Today, her monthly INR is 3.2.

Action: Assess why INR may be elevated and correct. Consider no change or decrease Warfarin by 10% to rowG of the protocol. Repeat INR in 1 week.

Example 2: 92 year old male intolerant of ASA/plavix and high risk for CVA. MD orders “INR protocol”

Action: Notify MD that protocol not be used for initiation and direct to Physician’s Order Sheet.

INR Protocol

Resident: ______

Indication (check one): □ Atrial Fibrillation □ Deep Vein Thrombosis □ Pulmonary Embolism

□ Mechanical Valve □ Cerebrovasular Accident □ Other:______

INR Range: □ 2.0 – 3.0 □ 2.5 – 3.5 □ Other (excluded from protocol)

Start Date: ___/___/___ Therapy Duration: □ Indefinite □ Other: ______

Anticoagulation Flow Sheet

Date / Current Dose
(Row) / INR / New Dose
(Row) / Next INR / Initials
Ie. 11/7/2011 / H / 3.2 / G / 11/14/2011 / HP RN(EC)