Clinical Resources

Head Injury in Patients on Anticoagulants

Why any head injury in a patient taking warfarin or a direct oral anticoagulant requires emergency department assessment, and how to identify features that require calling 999.

Published 29 May 2026

Why this matters

Patients taking anticoagulant medicines, including warfarin, apixaban, rivaroxaban, edoxaban, dabigatran, low molecular weight heparins such as enoxaparin, and fondaparinux, 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 recommends emergency department assessment for patients taking anticoagulants who sustain a head injury.¹ CT imaging is generally considered even when no other CT indications are present, and should follow current NICE NG232 guidance.¹

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, low molecular weight heparins (such as enoxaparin), or fondaparinux

What to do in pharmacy

Call 999 immediately for any of the following: any loss of consciousness after the injury, even if the patient appears well now; any seizure after a head injury; any new neurological symptom such as weakness, difficulty speaking, visual disturbance, or confusion; a worsening headache together with vomiting; a deteriorating level of consciousness; amnesia for events before or after the injury. These features indicate possible serious intracranial injury. Deterioration can occur quickly. Do not wait to see if symptoms progress before calling 999.

Send to the Emergency Department (ED) the same day for any head injury in a patient who is taking an anticoagulant (warfarin, apixaban, rivaroxaban, edoxaban, dabigatran, low molecular weight heparins such as enoxaparin, or fondaparinux), even if the injury seems minor and the patient feels completely well. NICE NG232 recommends considering computed tomography (CT) head imaging within 8 hours for anticoagulated patients, even when no other CT indications are present.¹ Any concern about delayed symptoms such as increasing headache or unsteadiness should also prompt same-day assessment. When advising on pain relief, recommend paracetamol. Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) can increase bleeding risk and should be avoided after a head injury. Antiplatelet medicines such as aspirin, clopidogrel, ticagrelor and prasugrel also increase bleeding risk, although NICE referral criteria differ from those for anticoagulants.

Self-care is appropriate only when the patient is not taking an anticoagulant, the injury was clearly minor, the patient remained fully alert throughout, and there was no loss of consciousness, no vomiting, no amnesia, and no neurological symptoms. Do not rely on absence of symptoms immediately after injury. A responsible adult should be present to observe the person for 24 hours, and patients should not drive themselves to hospital if they later need assessment. Paracetamol may be used for pain relief. Safety-net: seek urgent medical help immediately if any of the following develop in the next 24 hours: worsening headache, vomiting, drowsiness, unusual behaviour, confusion, weakness, difficulty speaking, visual disturbance, or any other neurological symptoms.

Key takeaways

Any head injury in a patient taking an anticoagulant requires assessment in the Emergency Department, even if they feel completely well. Intracranial bleeding can be silent at first and then deteriorate rapidly.
NICE NG232 recommends considering computed tomography (CT) head imaging within 8 hours for anticoagulated patients with a head injury, even when no other CT indications are present. 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.

📚 References

National Institute for Health and Care Excellence. Head injury: assessment and early management. NICE guideline NG232. London: NICE; 2023 https://www.nice.org.uk/guidance/ng232

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