WARFARIN:OVERANTICOAGULATION

High risk patients

Co-morbidity

• Affecting clotting factor synthesis, vitamin K availability or warfarin metabolism
• cardiac failure
• gastrocolic fistula
• liver disease
• malnutrition
• cholestasis
• abrupt weight reduction
• diarrhoea
• renal impairment
• thyrotoxicosis
• fever
• malignancy
• aged >75 yr

Medications

• Many. Check interactions in the BNF. Use an alternative agent if possible
• most antimicrobials
• concurrent anti-platelet, NSAID, SSRI or SNRI
• Over dosage (accidental or deliberate)

Referral

• Refer patients to the local anticoagulation team for regular monitoring and dosing during inpatient stay and post-discharge

Prosthetic heart valves

• Reversal of anticoagulation may increase the risk of valve thrombosis
• in non-life, limb or sight threatening situations, discuss management with cardiothoracic unit and haematologist

Management of warfarin

• Management of over-anticoagulation depends on the INR, severity of bleeding and underlying thrombotic risk

• Major haemorrhage
• life, limb or sight threatening bleeding including high suspicion pre-imaging
• intra-cerebral bleed
• bleed with haemodynamic instability
• major trauma
• intraocular bleed (excluding subconjunctival)
• muscle bleed resulting in compartment syndrome
• pericardial bleed
• Minor haemorrhage and INR raised
• High INR without bleeding

Other management

• Intracranial bleeding in association with warfarin therapy is a medical emergency
• if there is a high clinical suspicion of ICH, do not wait for INR result or imaging
• urgent assessment, imaging and treatment
• seek neurosurgery advice
• Consider local, endoscopic, interventional radiological and surgical measures early for all bleeds
• Investigate cause for elevated INR

• Report any patient with anticoagulation associated bleeding to hospital incident system
• Review the need for anticoagulation; confirm duration, intensity and concurrent medication
• Assess bleeding risk factors and address any potential cause for re-bleeding
• Seek specialist input from relevant team e.g. neurosurgery, gastroenterology
• Discuss with the haemostasis team before re-starting anticoagulation
• Assess suitability of alternative anticoagulants
• All cases will be reviewed by the local anticoagulation team