Does Jakafi cause confusion? Understanding neurological side effects

October 10, 2025 •

3 min read

Reports indicate that confusion can occur while taking Jakafi (ruxolitinib), and it can sometimes be a sign of a serious underlying condition. It is crucial for patients and caregivers to be aware of this potential adverse effect and know when to seek immediate medical attention.

Quick Summary

Jakafi can lead to confusion, which may indicate a severe brain infection (PML) or a cardiovascular event (stroke). Patients must be vigilant for cognitive changes and other neurological symptoms, reporting them immediately to a healthcare provider.

Key Points

Confusion on Jakafi: While not a common side effect, confusion is a potential risk for patients taking Jakafi (ruxolitinib) and may indicate a serious underlying condition.
PML Risk: Confusion can be a symptom of Progressive Multifocal Leukoencephalopathy (PML), a rare but serious viral brain infection associated with Jakafi's immunosuppressive effects.
Stroke and Blood Clots: Jakafi can increase the risk of cardiovascular events, and sudden confusion is a key symptom of a stroke or serious blood clot, requiring immediate emergency care.
Infection-Related Confusion: The risk of infection is higher with Jakafi, and a severe infection can cause delirium and confusion, especially if accompanied by a fever.
Immediate Medical Attention: All instances of new or worsening confusion should be reported to a healthcare provider immediately for prompt evaluation to determine the cause and appropriate action.

Jakafi (Ruxolitinib) and Neurological Symptoms

Jakafi (ruxolitinib) is a Janus kinase (JAK) inhibitor used to treat specific blood disorders, including myelofibrosis, polycythemia vera, and chronic graft-versus-host disease (cGVHD). While it effectively manages these conditions, it carries a risk of various side effects, some of which are neurological and can manifest as confusion. It is important to note that confusion is not a typical common side effect but can be an indicator of more serious underlying issues requiring urgent medical intervention.

Progressive Multifocal Leukoencephalopathy (PML)

One of the most serious and potentially deadly neurological side effects associated with Jakafi is Progressive Multifocal Leukoencephalopathy (PML). PML is a rare viral brain infection that primarily affects individuals with compromised immune systems. Because Jakafi suppresses the immune system, patients are at a higher risk.

Symptoms of PML can develop over several weeks or months and may include a range of cognitive and motor problems. Confusion is a prominent symptom, often accompanied by:

Memory loss
Changes in mood or behavior
Difficulty thinking or speaking
Changes in vision
Weakness or decreased strength on one side of the body
Loss of balance or coordination

Cardiovascular Events: Stroke and Blood Clots

Jakafi has been linked to an increased risk of serious cardiovascular events, including heart attack and stroke. A stroke can be a direct cause of sudden confusion and other neurological deficits. Signs of a stroke require immediate emergency medical attention.

Symptoms of a stroke that may be confused with other issues but are crucial to recognize include:

Sudden confusion
Slurred speech or trouble speaking
Weakness or numbness in the face, arm, or leg, especially on one side
Trouble seeing in one or both eyes
Sudden, severe headache

Infection-Related Confusion

Jakafi's immunosuppressive properties increase the risk of infection, such as shingles (herpes zoster), tuberculosis, and others. In some cases, a severe infection can cause delirium, which includes acute confusion. This is particularly true if the infection leads to fever, which can further exacerbate cognitive symptoms. Symptoms of a serious infection to watch for, in addition to confusion, are:

Fever or chills
Feeling unwell or fatigued
Sore throat or cough
Pain or burning with urination

Recognizing and Responding to Confusion

Since confusion while on Jakafi can be a symptom of a life-threatening condition, prompt action is critical. Patients and caregivers should be trained to recognize the signs and understand the necessary steps.

Here are the critical steps to take if cognitive changes occur:

Assess the situation: Note the nature of the confusion (e.g., disorientation, memory loss, altered behavior), how suddenly it occurred, and if there are any other accompanying symptoms.
Contact a healthcare provider immediately: Do not delay. Call your doctor's office or seek emergency care if the symptoms are severe or sudden.
Provide information: Be prepared to tell the medical team about the patient's full medical history, current medications, and the timeline of the new symptoms. Mentioning that the patient is on Jakafi is essential.
Do not stop taking Jakafi without medical advice: Discontinuing Jakafi abruptly can cause severe withdrawal symptoms, so it is vital to follow a doctor's guidance.

Comparison of Serious Neurological Symptoms


Symptom	Progressive Multifocal Leukoencephalopathy (PML)	Stroke / Blood Clots	Severe Infection
Onset of Confusion	Can be gradual, developing over weeks or months.	Can be very sudden and dramatic.	Can be acute, especially with fever.
Associated Symptoms	Memory problems, behavioral changes, weakness on one side, speech difficulties.	Weakness or numbness on one side of body, slurred speech, severe headache, vision trouble.	Fever, chills, cough, flu-like symptoms, pain with urination.
Urgency	High, requires immediate medical evaluation and treatment.	Highest, requires immediate emergency care (call 911).	High, requires prompt medical evaluation to identify the cause.

Conclusion

While confusion is a less common side effect, it is a significant warning sign for anyone taking Jakafi. It is not something to be ignored and can signal a serious, life-threatening condition such as PML, a stroke, or a severe infection. Awareness, prompt recognition of symptoms, and rapid communication with a healthcare team are the most effective ways to manage this risk. Patients should maintain open communication with their medical providers and caregivers should also be vigilant for any changes in the patient's cognitive state or behavior. Immediate medical attention is the critical next step in ensuring patient safety when confusion occurs.

For more detailed information on Jakafi's risks and management, patients can consult the resources available on Cancer.gov.

Frequently Asked Questions

Jakafi is a prescription medication with the active ingredient ruxolitinib. It is primarily used to treat certain blood and bone marrow cancers, such as myelofibrosis and polycythemia vera, and to treat chronic graft-versus-host disease (cGVHD).

No, confusion is not considered a common side effect of Jakafi. It is, however, a potential symptom of more serious, albeit rare, adverse events that require immediate medical attention, such as PML, stroke, or a severe infection.

If you experience new or worsening confusion, you should contact your healthcare provider or seek emergency medical help immediately. This is particularly urgent if other symptoms like weakness, speech trouble, or vision changes are also present.

Yes, Jakafi has been linked to potential memory problems. Memory impairment, along with confusion, is listed as a possible symptom of Progressive Multifocal Leukoencephalopathy (PML), a rare brain infection associated with the medication.

Jakafi can increase the risk of PML because it suppresses the immune system. This allows a normally dormant virus (the JC virus) to become active, leading to the severe brain infection.

Yes. Jakafi is associated with an increased risk of cardiovascular issues like stroke, and sudden confusion is a common symptom of a stroke. You should get emergency help right away if you suspect a heart attack or stroke.

Several types of medications can cause or contribute to confusion, especially in susceptible individuals or when combined. Examples include opioids, benzodiazepines, and other immunosuppressants.