Investigating the Link: Do Blood Thinners Cause Confusion?

October 10, 2025 •

4 min read

Anticoagulants are consistently identified as one of the most common causes of adverse drug events (ADEs) in healthcare [1.7.1]. For patients and caregivers, this raises an important question: do blood thinners cause confusion, and what does it mean if it happens?

Quick Summary

While confusion is not a common direct side effect, blood thinners can indirectly cause cognitive changes through serious complications like intracranial hemorrhage or cerebral microbleeds. Recognizing symptoms is critical.

Key Points

Indirect Cause: Confusion is more often an indirect symptom of a serious complication like a brain bleed (intracranial hemorrhage), rather than a direct drug side effect [1.5.2].
Medical Emergency: Sudden confusion, a severe headache, or vision changes while taking blood thinners require immediate medical attention (call 911) as they can signal a brain bleed [1.9.1].
Risk Factors: Advanced age, a history of falls, high blood pressure, and certain medical conditions increase the risk of bleeding complications that can cause confusion [1.7.5, 1.9.2].
Types Matter: Different blood thinners have different risk profiles; Direct Oral Anticoagulants (DOACs) are generally associated with a lower risk of intracranial bleeding than warfarin [1.4.2].
Microbleeds: Long-term anticoagulant use, particularly with warfarin, is associated with cerebral microbleeds, which are linked to cognitive decline [1.8.1, 1.8.2].
Diagnosis is Crucial: If confusion occurs, doctors use brain imaging like CT scans to quickly check for bleeding and determine the cause [1.9.4].
Patient Vigilance: Anyone on blood thinners who experiences a fall or head injury should seek medical evaluation, even if symptoms seem minor initially [1.9.2].

Understanding Blood Thinners and Their Purpose

Blood thinners, medically known as anticoagulants and antiplatelets, are essential medications prescribed to prevent the formation of dangerous blood clots [1.2.5]. They are commonly used by individuals with conditions like atrial fibrillation (an irregular heartbeat), deep vein thrombosis (DVT), and those who have had heart valve replacements. While anticoagulants like warfarin and Direct Oral Anticoagulants (DOACs) work by slowing down the clotting process, antiplatelet drugs like aspirin prevent blood cells called platelets from clumping together [1.2.4, 1.3.3]. Although vital for preventing strokes and other blockages, these medications carry a significant risk of bleeding [1.7.5].

Do Blood Thinners Cause Confusion? The Direct and Indirect Links

Directly, confusion is not a frequently reported side effect for most blood thinners, though it has been noted in some cases, particularly with older adults taking medications like Eliquis (apixaban) [1.2.2]. However, the more critical connection is indirect. Confusion is a primary symptom of a serious, life-threatening complication associated with blood thinners: an intracranial hemorrhage (ICH), or a brain bleed [1.5.2, 1.9.1]. A bleed inside the skull increases pressure on the brain, preventing oxygen from reaching brain tissue, which can lead to sudden confusion, severe headache, dizziness, and neurological deficits [1.5.2]. This is a medical emergency requiring immediate attention [1.5.2].

Another indirect link involves cerebral microbleeds (CMBs). These are tiny deposits of blood in the brain that can accumulate over time [1.8.3]. Studies show that anticoagulant use is correlated with the presence of these microbleeds [1.8.1]. A higher number of CMBs is associated with an increased risk of cognitive impairment and dementia [1.8.3].

Comparison of Common Blood Thinner Types

Different classes of blood thinners have varying risk profiles. Understanding these differences is key for patient management.


Medication Type	Common Names	Primary Mechanism	Cognitive-Related Side Effects & Risks
Vitamin K Antagonists (VKAs)	Warfarin (Coumadin)	Inhibits vitamin K-dependent clotting factors.	Linked to higher rates of dementia in some long-term studies, especially with poor INR control [1.2.3, 1.6.4]. Higher risk of new cerebral microbleeds compared to DOACs [1.8.2].
Direct Oral Anticoagulants (DOACs)	Apixaban (Eliquis), Rivaroxaban (Xarelto), Dabigatran (Pradaxa), Edoxaban (Savaysa)	Directly inhibit specific clotting factors (Factor Xa or thrombin).	Generally associated with a lower risk of dementia and intracranial hemorrhage compared to warfarin [1.4.2, 1.4.4]. Confusion is listed as a rare side effect for some, like apixaban [1.2.2].
Antiplatelets	Aspirin, Clopidogrel (Plavix)	Prevent platelets from sticking together to form a clot.	Some studies suggest antiplatelet therapy is associated with an increased risk of dementia compared to no treatment or warfarin [1.2.4].

Key Risk Factors for Cognitive Complications

Certain factors can increase an individual's vulnerability to bleeding and subsequent cognitive issues while on blood thinners:

Advanced Age: Older adults are more prone to bleeding complications [1.7.5].
History of falls or head trauma: Any head injury, even minor, increases the risk of a brain bleed while on these medications [1.9.2].
High Blood Pressure: Uncontrolled hypertension weakens blood vessels.
Kidney or Liver Disease: These conditions can affect how the body processes the medication, increasing bleeding risk [1.7.5].
Pre-existing Cognitive Impairment: Patients with cognitive issues may be at higher risk for major bleeding or death while on anticoagulants [1.3.6].
Polypharmacy: Taking multiple medications can lead to interactions that increase bleeding risk.

Recognizing Emergency Warning Signs

If you or someone you know is taking a blood thinner, it is crucial to recognize the signs of a potential brain bleed. Seek immediate emergency medical care by calling 911 if any of the following occur:

Sudden, severe headache [1.5.2]
Sudden onset of confusion or disorientation [1.5.6]
Weakness, numbness, or paralysis, especially on one side of the body [1.5.2]
Slurred speech or difficulty speaking [1.5.3]
Dizziness, loss of balance, or coordination problems [1.5.2]
Changes in vision, such as blurred or double vision [1.5.3]
Nausea and vomiting [1.5.2]
Seizures [1.5.3]

Diagnosis and Management

When a patient on blood thinners presents with confusion, doctors will act quickly to diagnose the cause. This typically involves a neurological exam and immediate neuroimaging, such as a CT scan or MRI of the head, to check for bleeding [1.9.4]. Blood tests will also be performed to assess clotting levels.

If an intracranial hemorrhage is confirmed, management involves stopping the anticoagulant and, if available, administering a reversal agent. For warfarin, this is Vitamin K; for certain DOACs, reversal agents like Andexxa are used. The patient will require hospitalization for close monitoring and supportive care to manage brain swelling and other complications.

Conclusion

So, do blood thinners cause confusion? While it is not a common direct side effect, the potential for blood thinners to cause life-threatening bleeding inside the brain—with confusion as a key symptom—is a serious and well-established risk [1.5.1, 1.5.2]. The link is more often indirect, a sign of a medical emergency rather than a benign side effect. Patient education on recognizing the warning signs of a brain bleed is paramount. Prompt communication with healthcare providers about any new symptoms, falls, or injuries, and seeking immediate emergency care for acute neurological changes can be lifesaving. For more information on anticoagulant safety, a valuable resource is the American Heart Association [1.9.1].

Frequently Asked Questions

While not common, dizziness and confusion have been reported as side effects of Eliquis (apixaban), particularly in older adults. However, any sudden cognitive change could also be a sign of a more serious issue like a brain bleed and should be evaluated by a doctor immediately [1.2.2].

If confusion is caused by a brain bleed, the outcome depends on the severity of the bleed and how quickly treatment is administered. Prompt medical intervention to stop the bleeding and reduce pressure on the brain is critical to minimize long-term brain damage [1.5.2].

Studies suggest long-term use of warfarin, especially with poor INR control, is associated with higher rates of dementia and cerebral microbleeds compared to DOACs [1.2.3, 1.8.2]. DOACs are generally linked with a lower risk of cognitive decline [1.4.2].

Treat it as a medical emergency. Call 911 immediately. Sudden confusion can be a primary symptom of an intracranial hemorrhage (brain bleed), which requires urgent medical treatment [1.9.1].

Manage risk factors by controlling blood pressure, preventing falls by making your home safer (e.g., removing trip hazards), and having regular medication reviews with your doctor. Always inform your doctor about any falls or injuries [1.6.3].

Yes, you should never stop taking a blood thinner without consulting your doctor. Suddenly stopping can significantly increase your risk of developing the dangerous blood clots the medication is meant to prevent [1.2.2].

The choice of medication depends on the reason for anticoagulation. For some patients, switching from warfarin to a DOAC may lower bleeding risk [1.4.2]. In specific cases of atrial fibrillation, a device like the Watchman may be an option to reduce stroke risk without long-term anticoagulants. Always discuss options with your cardiologist.