Pronunciation: JAK-ah-fye
Generic name: ruxolitinib
Dosage form: oral tablets (5 mg, 10 mg, 15 mg, 20 mg, 25 mg)
Drug class: Multikinase inhibitors

Medically reviewed by Carmen Pope, BPharm. Last updated on May 22, 2025.

What is Jakafi?

Jakafi is used to treat certain types of myelofibrosis (MF) or polycythemia vera (PV) in adults, and certain types of graft-versus-host disease in adults and children 12 years of age and older. It is an oral tablet that is taken 2 times a day.

Jakafi works by blocking specific proteins called JAK1 and JAK2 that send "grow and multiply" signals to blood cells and immune cells. By stopping these signals, Jakafi reduces abnormal cell growth in blood cancers like myelofibrosis/polycythemia vera and decreases harmful inflammation in graft-versus-host disease by suppressing inflammatory cytokines. It belongs to the drug class called kinase inhibitors.

Jakafi (ruxolitinib) gained FDA approval on November 16, 2011. No generic is available.

FDA approvals and indications

Jakafi is approved to treat:

• Intermediate or high-risk myelofibrosis (MF) (includes primary MF, post-polycythemia vera MF, and post-essential thrombocytopenia MF) in adults
• Polycythemia vera (PV) in adults who have had an inadequate response to, or are intolerant of, hydroxyurea
• Steroid-refractory acute graft-versus-host disease (aGVHD) in adults and children aged 12 years and older
• Chronic graft-versus-host-disease (cGVHD) in adults and children aged 12 years and older after failure of one or two lines of systemic therapy.

It is not known if Jakafi is safe or effective in children with MF or PV, or children under 12 with GVHD.

Jakafi side effects

The most common side effects of Jakafi in adults with MF and PV are:

• low platelet counts
• low red blood cell counts
• bruising
• dizziness
• headache
• diarrhea.

The most common side effects of Jakafi in people with aGVHD are:

• low red blood cell counts
• low platelet counts
• low white blood cell counts
• infections
• swelling.

The most common side effects of Jakafi in people with cGVHD are:

• low red blood cell counts
• low platelet counts
• infections, including viral infections.

Serious side effects and warnings

Jakafi can cause the following serious side effects:

• Low blood cell counts. Jakafi may cause low platelet counts (thrombocytopenia), low red blood cell counts (anemia), and low white blood cell counts (neutropenia). If you develop bleeding, stop Jakafi and call your healthcare provider. Your healthcare provider will do a blood test to check your blood cell counts before you start Jakafi and regularly during your treatment with Jakafi. Tell your healthcare provider right away if you develop or have worsening of any of these symptoms:
  • unusual bleeding
  • bruising
  • tiredness
  • shortness of breath
  • fever.
• Infection. You may be at risk for developing a serious infection during treatment with Jakafi. Tell your healthcare provider if you develop any of the following symptoms of infection:
  • chills
  • aches
  • fever
  • nausea
  • vomiting
  • weakness
  • painful skin rash or blisters.
• Cancer. Some people have had certain types of non-melanoma skin cancers during treatment with Jakafi. Your healthcare provider will regularly check your skin during your treatment with Jakafi. Tell your healthcare provider if you develop any new or changing skin lesions during treatment with Jakafi.
• Cholesterol increases. You may have changes in your blood cholesterol levels during treatment with Jakafi. Your healthcare provider will do blood tests to check your cholesterol levels about every 8 to 12 weeks after you start taking Jakafi, and as needed.
• Increased risk of major cardiovascular events such as heart attack, stroke, or death in people who have cardiovascular risk factors and who are current or past smokers while using another JAK inhibitor to treat rheumatoid arthritis. Get emergency help right away if you have any symptoms of a heart attack or stroke while taking Jakafi, including:
  • discomfort in the center of your chest that lasts for more than a few minutes, or that goes away and comes back
  • severe tightness, pain, pressure, or heaviness in your chest, throat, neck, or jaw
  • pain or discomfort in your arms, back, neck, jaw, or stomach
  • shortness of breath with or without chest discomfort
  • breaking out in a cold sweat
  • nausea or vomiting
  • feeling lightheaded
  • weakness in one part or on one side of your body
  • slurred speech.
• Increased risk of blood clots. Blood clots in the veins of your legs (deep vein thrombosis, DVT) or lungs (pulmonary embolism, PE) have happened in people taking another JAK inhibitor for rheumatoid arthritis and may be life-threatening. Tell your healthcare provider right away if you have any signs and symptoms of blood clots during treatment with Jakafi, including:
  • swelling, pain, or tenderness in one or both legs
  • sudden, unexplained chest or upper back pain
  • shortness of breath or difficulty breathing.
• Possible increased risk of new (secondary) cancers. People who take another JAK inhibitor for rheumatoid arthritis have an increased risk of new (secondary) cancers, including lymphoma and other cancers. People who smoke or who smoked in the past have an added risk of new cancers.

These are not all the possible side effects of Jakafi. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects to Incyte Corporation at 1-855-463-3463.

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Before taking

Before taking Jakafi, tell your healthcare provider about all of your medical conditions, including if you:

• have an infection
• have or have had low white or red blood cell counts
• have or had tuberculosis (TB), or have been in close contact with someone who has TB
• have had shingles (herpes zoster)
• have or had hepatitis B
• have or have had liver problems
• have or have had kidney problems or are on dialysis. If you are on dialysis, Jakafi should be taken after your dialysis.
• have a high level of fat in your blood (high blood cholesterol or triglycerides)
• have had cancer in the past
• are a current or past smoker
• have had a blood clot, heart attack, other heart problems or stroke
• are pregnant or plan to become pregnant. It is not known if Jakafi will harm your unborn baby.
• are breastfeeding or plan to breastfeed. It is not known if Jakafi passes into your breast milk. Do not breastfeed during treatment with Jakafi and for 2 weeks after the final dose.

How should I take Jakafi?

Take Jakafi exactly as your healthcare provider tells you. Do not change your dose or stop taking Jakafi without first talking to your healthcare provider.

• Jakafi is usually taken 2 times a day.
• You can take Jakafi with or without food.
• It may also be given through certain nasogastric tubes.

Tell your healthcare provider if you cannot take Jakafi by mouth. Your healthcare provider will decide if you can take Jakafi through a nasogastric tube.

• Ask your healthcare provider to give you specific instructions on how to properly take Jakafi through a nasogastric tube.

You will have regular blood tests during your treatment with Jakafi. Your healthcare provider may change your dose of Jakafi or stop your treatment based on the results of your blood tests.

Dosing information

Usual Jakafi dose for myelofibrosis

Dosage is based on the patient’s baseline platelet count

• Greater than 200 x 10⁹/L: 20 mg twice daily
• 100 x 109/L to 200 x 10⁹/L: 15 mg twice daily
• 50 x 109/L to less than 100 x 10⁹/L: 5 mg twice daily.

Monitor complete blood counts every 2 to 4 weeks until doses are stabilized, and then as clinically indicated. Modify or interrupt dosing for thrombocytopenia.

Usual Jakafi dose for Polycythemia Vera

• Starting dose: 10 mg twice daily.

Usual Jakafi dose for acute Graft-versus-host-disease (aGVHD)

• Starting dose: 5 mg twice daily.

Usual Jakafi dose for chronic graft-versus-host disease (cGVHD)

• Starting dose: 10 mg twice daily.

What happens if I miss a dose?

If you miss a dose of Jakafi, take your next dose at your regular time. Do not take 2 doses at the same time.

What happens if I take too much?

If you take too much Jakafi, call your healthcare provider or go to the nearest hospital emergency room right away.

What other drugs will affect Jakafi?

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Taking Jakafi with certain other medicines may affect how Jakafi works. Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist when you get a new medicine.

Storage

Store Jakafi at room temperature 68°F to 77°F (20°C to 25°C).

Keep out of the reach of children.

Ingredients

Active ingredient: ruxolitinib phosphate

Inactive ingredients: microcrystalline cellulose, lactose monohydrate, magnesium stearate, colloidal silicon dioxide, sodium starch glycolate, povidone, and hydroxypropyl cellulose.

Jakafi is available as 5 mg, 10 mg, 15 mg, 20 mg, and 25 mg tablets.

Who makes Jakafi?

Jakafi is made by Incyte Corporation, located in Wilmington, DE 19803.

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Further information

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