Head Injury in Patients on Anticoagulants
Why any head injury in a patient taking warfarin or a direct oral anticoagulant requires Accident and Emergency assessment, and how to identify features that require calling 999.
Why this matters
Patients taking anticoagulant medicines such as warfarin, apixaban, rivaroxaban, edoxaban, dabigatran, or heparin have a much higher risk of bleeding inside the skull after a head injury. Even a very minor bump that would cause no more than a bruise in a healthy adult can result in a life-threatening intracranial haemorrhage in someone whose blood does not clot normally. Bleeding inside the skull may not cause symptoms immediately. A patient can feel well for several hours before suddenly deteriorating.
Community pharmacists are in a key position to recognise this. A patient on an anticoagulant who asks for paracetamol after hitting their head has a clinical need for medical assessment, not simply pain relief. NICE NG232 states that every head injury in a patient taking an anticoagulant must be assessed in the emergency department, with a computed tomography (CT) head scan within 8 hours.
Red flags vs more likely benign
| Feature | More likely benign | Red flag ⚠ |
|---|---|---|
| Consciousness | Fully alert throughout with no blackout | Any loss of consciousness, even if brief |
| Headache | Mild, short-lived, no change from baseline | Persistent or worsening headache |
| Vomiting | None | Any vomiting after the injury, which may indicate raised intracranial pressure |
| Neurological symptoms | None | Confusion, new weakness, difficulty speaking, or visual disturbance |
| Amnesia | None | Memory loss before or after the injury |
| Mechanism | Low-force impact with no significant blow | Fall from height, road traffic collision, or assault |
| Anticoagulants | Not prescribed | Taking warfarin, apixaban, rivaroxaban, edoxaban, dabigatran, or heparin |
What to do in pharmacy
Key takeaways
- Any head injury in a patient taking an anticoagulant requires assessment in Accident and Emergency, even if they feel completely well. Intracranial bleeding can be silent at first and then deteriorate rapidly.
- NICE NG232 recommends computed tomography (CT) head imaging within 8 hours for all anticoagulated patients with a head injury. Home observation is not appropriate.
- Always check anticoagulant status when giving advice for pain after a head injury. Paracetamol is suitable. Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) increase bleeding risk.