Jakafi (ruxolitinib) is a JAK inhibitor that’s used to treat adults with certain blood conditions called myelofibrosis (MF) and polycythemia vera (PV). This medication is also used to treat graft-versus-host disease (GVHD) in people 12 years and older. Jakafi (ruxolitinib) is a tablet that you take by mouth twice a day. It can cause side effects like low blood cell counts, infection, and tiredness.
Intermediate or high-risk myelofibrosis (MF) in adults
Polycythemia vera (PV) in adults who can’t take or have already tried hydroxyurea (Hydrea)
Acute graft-versus-host disease (aGVHD) in people 12 years and older who’ve already tried corticosteroids
Chronic graft-versus-host disease (cGVHD) in people 12 years and older who’ve already tried at least one therapy option already
Jakafi (ruxolitinib) is a JAK inhibitor. It works by blocking the activity of JAK proteins in the body.
In myelofibrosis and polycythemia vera, JAK proteins send signals that tell your blood cells to grow and divide too quickly. When Jakafi (ruxolitinib) blocks JAK, blood cells can’t grow out of control as well.
And in graft-versus-host disease, JAK proteins play a role in turning on the immune system and damaging tissues. By blocking JAK, Jakafi (ruxolitinib) helps prevent the immune system from becoming too active.
Source: DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
Black, tarry stools
bladder pain
bleeding gums
blood in the urine or stools
blurred vision
bruising
chills
cloudy urine
collection of blood under the skin
coughing up blood
deep, dark purple bruise
difficult, burning, or painful urination
difficulty in breathing or swallowing
dizziness
frequent urge to urinate
headache
hoarseness
increased menstrual flow or vaginal bleeding
itching, pain, redness, or swelling
large, flat, blue or purplish patches in the skin
lower back or side pain
nervousness
nosebleeds
painful or difficult urination
pale skin
paralysis
pinpoint red spots on the skin
pounding in the ears
prolonged bleeding from cuts
pus in the urine
red or dark brown urine
small, red or purple spots on the skin
slow or fast heartbeat
swelling
tenderness, pain, swelling, warmth, skin discoloration, and prominent superficial veins over the affected area
tightness in the chest
troubled breathing with exertion
ulcers, sores, or white spots in the mouth
unusual bleeding or bruising
unusual tiredness or weakness
Less common
Painful blisters on the trunk of the body
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Taken by mouth; no needles required
Recommended treatment for myelofibrosis and polycythemia vera
Doesn’t typically cause nausea or vomiting
Works in a more targeted, specific way than traditional chemotherapy
Taken twice a day and might require dose changes often
Often causes low blood cell counts
Might raise your risk for infection
You can take Jakafi (ruxolitinib) with or without food.
If you miss your Jakafi (ruxolitinib) dose, don’t take an extra dose of medication. Just wait until the next scheduled time to take Jakafi (ruxolitinib) at your usual dose.
Unless your oncologist or hematologist recommends it, you shouldn’t suddenly stop taking Jakafi (ruxolitinib). Otherwise, your symptoms might come back. Your prescriber will typically slowly lower your dose until you can completely stop the medication.
Your treatment plan with Jakafi (ruxolitinib) might need to change depending on your blood counts. Make sure you go to your lab appointments so your care team can check your blood counts and adjust your dose as needed.
Jakafi (ruxolitinib) can sometimes make your cholesterol levels go up. Your oncologist or hematologist will check your cholesterol levels every 2 to 3 months. Your prescriber might recommend medications like statins to help manage your cholesterol levels if they get too high. Your care team might also recommend adding different foods into your diet that can help lower cholesterol.
It might be harder for your body to fight infections while you’re taking Jakafi (ruxolitinib) because your white blood cell count can become low during treatment. You can help lower your risk for infections by avoiding crowds, washing your hands often, and washing raw fruits and vegetables well before eating them.
Give your oncology or hematology care team an up-to-date list of medications that you take. Update your list if you start any new medications or stop taking any. Certain drug interactions with Jakafi (ruxolitinib) can put you at risk for side effects from the cancer medication, while others can make the cancer medication work less well. Your care team can check that your medications are safe to take together.
You shouldn’t breastfeed while you’re taking Jakafi (ruxolitinib) and for 2 weeks after your last dose. We don’t know whether Jakafi (ruxolitinib) passes into human milk, but there’s a possible risk of harm to a nursing infant.
Jakafi (ruxolitinib) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
People who take Jakafi (ruxolitinib) can have a low blood cell count. This means that the number of red and white blood cells and platelets you have in your blood can drop. When your red blood cells are low, you might feel more tired. And because white blood cells help your body fight infection, you’re at risk for infection when you don’t have enough white blood cells to protect you. In addition, when your platelets are low, your body can’t stop bleeding as well.
You’ll need to get blood work every so often during treatment so your care team can check your blood count. If your blood count is too low, your oncologist or hematologist might recommend that you take a break from Jakafi (ruxolitinib) or take a lower dose of the medication until your blood count gets back up. If necessary, you might need a blood transfusion of red blood cells or platelets.
Risk factors: Travel to countries with high occurrence of tuberculosis | History of tuberculosis | History of herpes simplex infection
People who take Jakafi (ruxolitinib) have a higher risk of infection, including bacterial, fungal, and viral infections. Some infections that can develop during treatment, such as tuberculosis (TB), can be serious.
Before you start treatment, let your care team know about any infections you currently have or have had in the past. You shouldn’t start Jakafi (ruxolitinib) if you currently have a serious infection. Depending on what medical condition you’re taking Jakafi (ruxolitinib) for and your history of infections, you might need to take certain medications, such as an antibiotic or antiviral, to help prevent new infections.
Contact your care team right away if you have signs or symptoms of an infection, such as fever, cough, trouble breathing, muscle aches, chills, or severe tiredness.
Risk factors: Taking Jakafi (ruxolitinib) for myelofibrosis (MF) or polycythemia vera (PV)
Sometimes, people who stopped taking Jakafi (ruxolitinib) for myelofibrosis or polycythemia vera developed symptoms similar to those they had before treatment started. Some people also had fever, trouble breathing, low blood pressure, a blood-clotting condition called disseminated intravascular coagulation (DIC), or even organ failure.
Because of these risks, it’s important that you don’t suddenly stop taking Jakafi (ruxolitinib) without first talking with your oncologist or hematologist. Typically, your prescriber will slowly lower the dose (instead of suddenly stopping the medication). This helps prevent symptoms of your condition from coming back or other complications.
Some people developed a new skin cancer after they started taking Jakafi (ruxolitinib). Types of skin cancers that were reported included basal cell carcinoma, squamous cell carcinoma, and Merkel cell carcinoma. Make sure to regularly check your skin and contact your oncologist or a dermatologist if you notice any unusual changes.
Risk factors: Having risk factors for heart problems | Current or past smoker
People with rheumatoid arthritis who took a different JAK inhibitor than Jakafi (ruxolitinib) have had serious heart problems, such as heart attack, and stroke. Some of these problems were life-threatening. Jakafi (ruxolitinib) isn’t approved for use in rheumatoid arthritis.
Since JAK inhibitors like Jakafi (ruxolitinib) work similarly to each other, your oncologist or hematologist will discuss the possible risk for serious heart problems and stroke with you. They’ll consider the risks and benefits for you to take Jakafi (ruxolitinib). Call 911 right away if you have sudden chest pain; numbness on one side of the body; trouble breathing, speaking, or walking; or sudden nausea and sweating.
People with rheumatoid arthritis who took a different JAK inhibitor than Jakafi (ruxolitinib) have developed blood clots, including deep vein thrombosis (DVT) and pulmonary embolism (PE), during treatment. Jakafi (ruxolitinib) isn’t approved for use in rheumatoid arthritis.
Since JAK inhibitors like Jakafi (ruxolitinib) work similarly to each other, you should watch for symptoms of blood clots during treatment. Seek medical help right away if you have symptoms of a blood clot, such as swelling in one arm or one leg, sudden chest pain, and sudden trouble breathing.
Risk factors: New cancer that’s developed | Current or past smoker
People with rheumatoid arthritis who took a different JAK inhibitor than Jakafi (ruxolitinib) have a higher risk of developing new cancers, such as lymphoma. This risk appears to be even higher for people who smoke or have smoked in the past. Talk with your oncology or hematology care team if you’re concerned about the risk of developing a new cancer with Jakafi (ruxolitinib).
Myelofibrosis: The typical starting dose is either 5 mg, 15 mg, or 20 mg by mouth twice a day. It’ll depend on your platelet levels at the start of treatment. Your prescriber might adjust the dose during treatment based on your blood counts and your condition.
Polycythemia vera: The typical starting dose is 10 mg by mouth twice a day. Your prescriber might adjust the dose during treatment based on your blood counts and your condition.
Acute graft-versus-host disease: The typical starting dose is 5 mg by mouth twice a day for at least 3 days. Your prescriber might raise the dose to 10 mg twice a day depending on your blood counts.
Chronic graft-versus-host disease: The typical starting dose is 10 mg by mouth twice a day.
Your prescriber might recommend a lower starting dose if you have liver or kidney problems. Your starting dose might also be lower if you’re taking certain medications that can interact with Jakafi (ruxolitinib).
During treatment, your dose might be lowered if you have concerning side effects.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
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Abboud, R., et al. (2020). Insights into the role of the JAK/STAT signaling pathway in graft-versus-host disease. Therapeutic Advances in Hematology.
Abedin, S., et al. (2019). Efficacy, toxicity, and infectious complications in ruxolitinib-treated patients with corticosteroid-refractory graft-versus-host disease after hematopoietic cell transplantation. Biology of Blood and Marrow Transplantation.
American Cancer Society. (2021). How targeted therapies are used to treat cancer.
American Cancer Society. (2024). Anemia (low red blood cell counts).
American Cancer Society. (2024). Neutropenia (low white blood cell counts).
American Cancer Society. (2024). Thrombocytopenia (low platelet count).
American Red Cross. (n.d.). Blood transfusion process.
Arana Yi, C., et al. (2015). Efficacy and safety of ruxolitinib in the treatment of patients with myelofibrosis. Future Oncology.
Centers for Disease Control and Prevention. (n.d.). What you need to know: Neutropenia and risk for infection.
Incyte Corporation. (2023). Jakafi- ruxolitinib tablet [package insert]. DailyMed.
Jacobsohn, D. A., et al. (2007). Acute graft versus host disease. Orphanet Journal of Rare Diseases.
Leukemia & Lymphoma Society. (n.d.). Graft-versus-host disease.
Leukemia & Lymphoma Society. (n.d.). Lymphoma.
Leukemia & Lymphoma Society. (n.d.). Myelofibrosis.
Leukemia & Lymphoma Society. (n.d.). Polycythemia vera.
Lussana, F., et al. (2017). Ruxolitinib associated infections: A systematic review and meta-analysis. American Journal of Hematology.
MedlinePlus. (2023). Platelet count.
National Cancer Institute. (n.d.). Myelosuppression.
National Comprehensive Cancer Network. (2024). Myeloproliferative neoplasms.
National Heart, Lung, and Blood Institute. (2022). Disseminated intravascular coagulation (DIC).
Phillips, C. (2023). Drinking alcohol, often heavily, common among people with cancer and long-term survivors. National Cancer Institute.
Sabaawy, H. E., et al. (2021). JAK/STAT of all trades: Linking inflammation with cancer development, tumor progression and therapy resistance. Carcinogenesis.
Skin Cancer Foundation. (2024). Merkel cell carcinoma overview.
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