A summary of the most up to date BNSSG guidance can be found here.
The risk of bleeding is low in patients with INRs within the therapeutic range. However bleeding risk increases above an INR of 5.0. Individual patients may also have additional risk factors for bleeding.
In the event of major bleeding, referral to hospital for Prothrombin Complex Concentrate (PCC) or Fresh Frozen Plasma (FFP). The onset of action of these is quicker than reversal options in the community.
INR >12 is the maximum reported result. Admission not always needed for these very high INRs, but assessment is highly recommended to assess for underlying causes and risk (concurrent illness, bleeding risk including risk of falls, drug history).
There should be no need for a patient to attend the Emergency Department unless they are bleeding. If there are safety concerns the patient should be admitted under the medical team.
Higher thrombotic risk patients (mechanical heart valves/recurrent DVT/PE/CVE whilst on warfarin) may have a higher target INR. Caution is advised when treating these patients to ensure that INR levels do not dip too low, thereby risking thrombotic events.
For severe asymptomatic over-anticoagulation or over-anticoagulation with mild bleeding only, oral vitamin K is effective in most primary care settings. Low doses will effectively reverse anticoagulation and reduce the risk that patients will be resistant to subsequent re-anticoagulation. Intramuscular vitamin K is contraindicated because of the risk of muscle haematoma.
The recommended preparation is Konakion® MM paediatric 2mg in 0.2ml. This is an intravenous preparation but it can be given orally. The recommended dose corresponds to a very small volume and therefore appropriate oral syringes, provided by the manufacturer, need to be used. Some patients may need assistance.
The standard oral vitamin K 10mg tablet is not recommended.
Management Summary
- Result received by SevernSide IUC either from Haematology registrar/ Laboratory directly
- Clinician contacts the patient ASAP.
- Attempt to establish why control of their INR has been lost e.g. new medication which interacts with Warfarin, intercurrent illness, liver dysfunction, change in diet/ alcohol intake, accidental overdose
- Identify whether there are any bleeding complications.
- Identify any other risk factors and issues of patient safety
- Recommend and provide treatment. This depends on INR and whether bleeding is present:
| INR | SUGGESTED ACTION |
| 6.0 > INR < 8.0
No bleeding or minor bleeding Carefully assess the patient for additional risk factors e.g. age >70, epistaxis, previous bleeding complications*, patient has taken further dose warfarin since INR taken. |
1. Reduce warfarin dose or stop
2. Consider restarting when INR < 5.0 3. Consider oral 0.5-1mg vitamin K if other risk factors for bleeding (and consider the reason for anticoagulation). |
| INR > 8.0
No bleeding or minor bleeding Carefully assess the patient for additional risk factors e.g. age >70, epistaxis, previous bleeding complications*, patient has taken further dose warfarin since INR taken. |
INR >8.0
Assess patient, administer oral vitamin K 1mg and withhold warfarin. A lower dose (0.5mg) should be considered if high thrombotic risk – (mechanical heart valves/ previous CVE/ DVT whilst anticoagulated/ target INR >2.0-3.0). Consider a higher dose if there is a high bleeding risk. INR >10 Assess patient, administer oral vitamin k 2.5mg and withhold warfarin. Consider lower and higher doses as above. INR >12 Assess patient, administer oral vitamin k 5mg and withhold warfarin. Consider lower and higher doses as above. Consider restarting Warfarin when INR < 5.0 |
| Major Bleeding | Arrange urgent admission to hospital.
Treatment is intravenous Vitamin K 5-10mg and FFP/PCC. |
*It may be appropriate to arrange admission for observation for certain high risk patients.
Most patients are advised to take their warfarin/oral anticoagulant in the evening around 5-6pm, so it is important to try and speak to them before they take their dose. In the OOH setting, most patients will already have taken their warfarin dose by the time contact is made with them, in which case a further INR test the following day should always be considered. If the patient is not a higher thrombotic risk (mechanical heart valves/previous CVE/VTE whilst anticoagulated/target INR >2.0-3.0) and the result is received on Friday night, it may be appropriate to defer INR retesting until Monday morning, with advice to hold warfarin until this result is known.
If a housebound patient needs an INR test at the weekend this should be requested of the District Nursing Teams via Sirona Single Point of Access 0300 125 67 89.
Where IUC has requested testing OOH, there should be a plan to ensure that the result is checked and acted upon appropriately, with suitable communication with the patient.
If you cannot contact the patient and you have concerns about their welfare, consider requesting a home visit or police welfare check.
Mechanisms of warfarin dosing in BNSSG
- Pharmacy dosing: bloods generally taken at the GP surgery and high INRs generally dealt with by pharmacy/haematology registrar on-duty, but GP involvement if vitamin K is recommended
- Near Patient testing (finger prick) GP dosing: high results dealt with immediately
- Anticoagulant clinics at NBT and UHBW. Most INR tests are done on Mondays-Thursdays to avoid results becoming available after GPs close on a Friday
Detailed guidance on the management of over-anticoagulation is available from the British Committee for Standards in Haematology Guidelines on oral Anticoagulation.