What is Jakafi (Ruxolitinib)?
Jakafi, with the generic name ruxolitinib, is a targeted therapy medication known as a Janus kinase (JAK) inhibitor [1.5.1]. It works by blocking the activity of JAK1 and JAK2 proteins [1.5.2]. In certain blood and bone marrow cancers, these proteins can become overactive, leading to the abnormal production of blood cells and inflammation [1.5.1, 1.5.2]. Jakafi is prescribed to treat several conditions:
- Myelofibrosis (MF): A serious bone marrow disorder that disrupts the body's normal production of blood cells [1.3.1]. Jakafi is used for intermediate or high-risk cases [1.3.1].
- Polycythemia Vera (PV): A type of blood cancer where the body produces too many red blood cells, for patients who have not responded to or cannot tolerate hydroxyurea [1.3.1, 1.4.6].
- Graft-versus-Host Disease (GVHD): A condition that can occur after a stem cell or bone marrow transplant where the donor's cells attack the recipient's body [1.3.1, 1.4.6]. Jakafi is used for both acute and chronic GVHD when other treatments have not been effective [1.3.1].
By inhibiting the overactive JAK signaling pathway, Jakafi helps to control blood cell production, reduce inflammation, and alleviate symptoms like an enlarged spleen, night sweats, and itching [1.5.2, 1.3.3].
Can Jakafi Cause Fever?
Yes, fever (also referred to as pyrexia) is a recognized side effect of Jakafi [1.2.2, 1.2.7]. It's listed as a common side effect and can be a sign of infection, which patients on Jakafi are at an increased risk of developing [1.2.4, 1.3.5]. The medication's mechanism of action involves suppressing parts of the immune system, which can make it harder for the body to fight off bacteria, viruses, and other pathogens [1.3.2, 1.8.3].
Healthcare providers advise patients to report any signs of infection, such as fever, chills, sore throat, or a general feeling of being unwell, as soon as they appear [1.2.4]. It is crucial not to self-treat a fever while on this medication, as it could mask a more severe underlying issue that requires medical intervention [1.6.2]. A fever might be a direct side effect of the drug or, more seriously, an indication of an infection that needs prompt treatment [1.2.4].
Other Common and Serious Side Effects
Besides fever, Jakafi is associated with a range of other side effects. Regular monitoring, including blood tests, is essential to manage these potential risks [1.3.5, 1.6.2].
Common Side Effects
The most frequently reported side effects include:
- Low Blood Counts: This is a very common issue and can manifest as thrombocytopenia (low platelets), anemia (low red blood cells), and neutropenia (low white blood cells) [1.3.5, 1.4.3]. This can lead to symptoms like unusual bruising or bleeding, fatigue, shortness of breath, and an increased risk of infection [1.3.5, 1.2.4].
- Bruising: Occurs easily due to low platelet counts [1.2.3].
- Dizziness and Headache: These are common neurological side effects [1.2.5].
- Diarrhea: A frequent digestive issue experienced by patients [1.2.5].
- Weight Gain and Swelling: Some patients may experience fluid retention (edema) or an increase in weight [1.4.6].
Serious Side Effects and Black Box Warnings
Jakafi carries warnings for more severe health risks. The FDA has required warnings for JAK inhibitors regarding an increased risk of serious heart-related events, cancer, blood clots, and death [1.7.1, 1.7.3].
- Serious Infections: Jakafi can lower your ability to fight infections, leading to serious bacterial, viral, or fungal infections, including tuberculosis (TB) and shingles (herpes zoster) [1.8.3, 1.4.6].
- Major Adverse Cardiovascular Events (MACE): An increased risk of heart attack, stroke, or death has been noted, particularly in patients with existing cardiovascular risk factors like smoking [1.7.5, 1.7.3].
- Blood Clots: Deep vein thrombosis (DVT) in the legs or pulmonary embolism (PE) in the lungs are potential life-threatening risks [1.7.5].
- Skin Cancer: Patients may be at a higher risk for developing certain non-melanoma skin cancers [1.3.5]. Regular skin checks are recommended [1.3.5].
- Increased Cholesterol: Jakafi can cause a rise in cholesterol levels [1.7.5].
Jakafi Side Effects Comparison Table
| Side Effect Category | Examples | Management/Monitoring |
|---|---|---|
| Hematologic (Blood-related) | Anemia, Thrombocytopenia (low platelets), Neutropenia (low white blood cells), Bruising, Bleeding [1.3.5, 1.4.3] | Regular blood count monitoring; dose adjustments may be necessary. Report unusual fatigue, shortness of breath, or bleeding [1.3.5]. |
| Infectious | Fever, Chills, Shingles, UTIs, TB [1.2.4, 1.4.6, 1.8.3] | Report any signs of infection immediately. Avoid contact with sick individuals. Wash hands frequently [1.6.2]. |
| Cardiovascular | Heart attack, Stroke, Blood clots (DVT, PE) [1.7.5] | Inform your doctor of any heart disease history or risk factors (smoking, high cholesterol) [1.8.3]. Seek emergency help for chest pain, shortness of breath, or sudden weakness [1.8.2]. |
| Dermatologic | Non-melanoma skin cancers, Rash, Itching [1.3.5, 1.6.5] | Regular skin examinations by a healthcare provider. Use sun protection [1.6.2]. |
| General/Constitutional | Dizziness, Headache, Diarrhea, Weight gain, Fatigue [1.2.5, 1.4.6] | Discuss persistent symptoms with your doctor. Manage diarrhea with diet changes if approved. Get adequate rest [1.6.6, 1.6.2]. |
Managing Side Effects
Proactive communication with a healthcare provider is the cornerstone of managing Jakafi's side effects. Patients should never alter their dose or stop taking the medication without consulting their doctor, as this can cause symptoms to return or worsen [1.4.6, 1.8.4]. Before starting treatment, it's vital to inform the doctor about all existing medical conditions, including infections, heart problems, liver or kidney disease, and any history of cancer or blood clots [1.6.2, 1.8.3].
Patients should:
- Report Symptoms Promptly: Immediately inform a healthcare provider about fever, unusual bleeding, shortness of breath, symptoms of a heart attack or stroke, or any new skin lesions [1.3.5, 1.8.2].
- Attend Regular Check-ups: Blood tests are needed before and during treatment to monitor blood counts [1.3.5].
- Practice Infection Prevention: Wash hands often, avoid sick people, and be aware of the signs of infection [1.6.2].
- Protect Skin: Use sunscreen and undergo regular skin exams to check for skin cancer [1.6.2, 1.3.5].
- Avoid Grapefruit Juice: This can affect the amount of Jakafi in the blood [1.6.2].
Conclusion
So, can Jakafi cause fever? Yes, it is a known side effect, often signaling the body's increased susceptibility to infection due to the drug's immunosuppressive nature [1.2.4, 1.3.2]. While Jakafi is an effective treatment for myelofibrosis, polycythemia vera, and GVHD, it comes with a significant profile of potential side effects, from common issues like low blood counts and dizziness to serious risks including major cardiovascular events and secondary cancers [1.2.5, 1.7.5]. Close monitoring by a healthcare team and patient vigilance are essential for safely managing treatment and addressing any adverse reactions, like a fever, as soon as they arise.
For more detailed information, consult the Full Prescribing Information for Jakafi.
