How does Jakafi work?

Jakafi works by blocking the JAK protein signal. This protein signal is one of the signals responsible for the overproduction of blood cells and causes of inflammation. When this signal is blocked, it can’t get through to continue the abnormal process.

How do I stop taking Jakafi?

Never abruptly stop taking Jakafi unless specifically instructed by your healthcare provider. Stopping too quickly may cause changes in blood counts. Some people need to taper off the medication slowly.

Jakafi (Ruxolitinib) Oral: Use, Dosages, Side Effects

What Is Jakafi?

Jakafi (ruxolitinib) is an oral medication that is used to treat multiple conditions, including myeloproliferative disorders and graft-versus-host disease. It is in a class of medications called Janus kinase (JAK) inhibitors.

In the disorders that Jakafi treats, it works by slowing down an abnormal signal produced by cells. This abnormal signal, called JAK, can be responsible for causing too many blood cells to be made in the bone marrow. It can also lead to inflammation, which then causes damage.

Jakafi is used to block this abnormal protein signal in the conditions of:

Some types of myelofibrosis
Polycythemia vera
Types of graft-versus-host disease that hasn’t responded to other treatments

Drug Facts

Generic Name: Ruxolitinib

Brand Name(s): Jakafi

Drug Availability: Prescription

Therapeutic Classification: Kinase inhibitor

Available Generically: No

Controlled Substance: No

Administration Route: Oral

Active Ingredient: Ruxolitinib phosphate

Dosage Form(s): Tablet

What Is Jakafi Used For?

Jakafi is used for the following conditions:

Intermediate or high-risk myelofibrosis
Polycythemia vera in adults who can’t tolerate the medication Hydrea or when Hydrea no longer works
Acute graft-versus-host disease in people 12 years old and older for whom steroids didn’t work
Chronic graft-versus-host disease in people 12 years old and older who didn’t respond to one or two lines of therapy

Jakafi (Ruxolitinib) Drug Information - Illustration by Zoe Hansen — Verywell / Zoe Hansen

How to Take Jakafi

Jakafi is most often prescribed to be taken twice a day and can be taken with or without food. While taking Jakafi, you may need to undergo regular blood tests so your healthcare provider can monitor your treatment.

Storage

Store Jakafi tablets at room temperature (between 68 and 77 degrees Fahrenheit) away from moisture and heat. Do not store this medication in the bathroom. It should be kept in its original packaging.

Off-Label Uses

Studies have looked at the use of Jakafi both orally and topically in some skin conditions, such as:

How Long Does Jakafi Take to Work?

It can take months of taking Jakafi to notice an improvement in symptoms or blood counts.

What Are the Side Effects of Jakafi?

This is not a complete list of side effects and others may occur. A medical professional can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the U.S. Food & Drug Administration (FDA) at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

The most common side effects of Jakafi include:

Low platelets
Low red blood cells
Low white blood cells
Increased cholesterol levels
Bruising
Dizziness
Headache
Diarrhea
Infections
Swelling
Fluid retention

Severe Side Effects

There can be more serious side effects that may happen when taking Jakafi. Call your healthcare provider right away if you have serious side effects. Call 911 or go to the emergency room if you feel your symptoms are life-threatening or if you have a medical emergency. Serious side effects can include the following:

Increased risk of blood clots in the legs or the lungs
Risk of heart attack or stroke if also taking another JAK medication for rheumatoid arthritis
Development of non-melanoma skin cancers
Serious infections
New cancers, such as lymphoma, if taking another JAK medication for rheumatoid arthritis

Long-Term Side Effects

The long-term side effect risk of Jakafi is the possibility of causing new cancer. This risk is highest if someone is also taking other JAK medications.

Report Side Effects

Jakafi may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

(800) 332-1088

Dosage: How Much Jakafi Should I Take?

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

For oral dosage form (tablets):
- For acute graft-versus-host disease:
  - Adults and children 12 years of age and older—At first, 5 milligrams (mg) 2 times a day, depending on your blood test results. Your doctor will adjust your dose as needed and tolerated.
  - Children younger than 12 years of age—Use and dose must be determined by your doctor.
- For chronic graft-versus-host disease:
  - Adults and children 12 years of age and older—At first, 10 milligrams (mg) 2 times a day, depending on your blood test results. Your doctor will adjust your dose as needed and tolerated.
  - Children younger than 12 years of age—Use and dose must be determined by your doctor.
- For myelofibrosis:
  - Adults—At first, 5 to 20 milligrams (mg) 2 times a day, depending on your blood test results. Your doctor will adjust your dose as needed and tolerated. However, the dose is usually not more than 25 mg 2 times a day.
  - Children—Use and dose must be determined by your doctor.
- For polycythemia vera:
  - Adults—At first, 10 milligrams (mg) 2 times a day, depending on your blood test results. Your doctor will adjust your dose as needed and tolerated. However, the dose is usually not more than 25 mg 2 times a day.
  - Children—Use and dose must be determined by your doctor.

Modifications

If you are unable to take the tablets, Jakafi can also be given through certain nasogastric tubes. Your healthcare provider will determine if this is the right administration method for you.

The oral dose of Jakafi may be changed or modified based on the reason the medication was prescribed. If blood counts are not responding appropriately, your healthcare provider may increase your dose to reach the desired effect. Additionally, the dose may also be decreased if significant side effects are experienced.

Missed Dose

A missed dose of Jakafi should not be made up but should be taken at the next scheduled time. Never double up on doses.

Overdose: What Happens If I Take Too Much Jakafi?

If you take too much Jakafi, notify the prescribing healthcare provider immediately. Monitoring of blood counts may need to be done regularly to assess any significant changes after an overdose.

What Happens If I Overdose on Jakafi?

If you think you or someone else may have overdosed on Jakafi, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Jakafi, call 911 immediately.

911

Precautions

It is very important that your doctor check your progress at regular visits to make sure this medicine is working properly. Blood tests will be needed to check for unwanted effects.

If your condition does not improve within 6 months, or if it becomes worse, check with your doctor.

This medicine lowers the number of some types of blood cells in your body. Because of this, you may bleed or get infections (eg, herpes, tuberculosis, hepatitis B, progressive multifocal leukoencephalopathy, fungal infection). Avoid being near people who are sick or have infections while you are using this medicine. Wash your hands often. Stay away from rough sports or other situations where you could be bruised, cut, or injured. Brush and floss your teeth gently. Be careful when using sharp objects, including razors and fingernail clippers.

This medicine may increase your risk of a serious brain infection called progressive multifocal leukoencephalopathy (PML). Call your doctor right away if you have weakness on one side of your body, loss of coordination, clumsiness, memory problems, trouble thinking clearly, or loss of interest in things.

Check with your doctor right away if you have painful blisters on the trunk of the body. These may be symptoms of herpes zoster (shingles).

Do not stop using this medicine suddenly without asking your doctor. You may need to slowly decrease your dose before stopping it completely. This may help prevent a possible worsening of your condition and reduce the possibility of withdrawal symptoms such as a fever, chest tightness, trouble breathing, lightheadedness, dizziness, or fainting.

This medicine may increase your risk of cancer (eg, lymphoma, non-melanoma skin cancer). Tell your doctor right away if you have black, tarry stools, general feeling of illness, swollen glands, weight loss, yellow skin and eyes, persistent non-healing sore, reddish patch or irritated area, shiny bump, pink growth, or white, yellow or waxy scar-like area on the skin.

This medicine may increase your risk of serious heart or blood vessel problems, including heart attack or stroke. Call your doctor right away if you have chest pain or discomfort, confusion, difficulty in speaking, double vision, headache, inability to move arms, legs, or facial muscles, nausea, pain or discomfort in the arms, jaw, back, or neck, sweating, trouble breathing, or vomiting.

Check with your doctor right away if you have anxiety, chest pain, cough, dizziness, lightheadedness, or fainting, fast heartbeat, pain, redness, or swelling in the arm or leg, pains in the chest, groin, or legs, especially calves of the legs, severe headaches, sudden loss of coordination, sudden onset of slurred speech, sudden vision changes, or trouble breathing. These may be symptoms of serious blood clots (eg, deep vein thrombosis, pulmonary embolism, arterial thrombosis).

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What are Reasons I Shouldn't Take Jakafi?

Jakafi shouldn’t be taken by people who are pregnant, as it has not been studied in this population and there is a chance of harm to the fetus.

Additionally, Jakafi shouldn’t be taken by people who are breastfeeding.

What Other Medications Interact With Jakafi?

Do not take the medication fluconazole, available under the brand name Diflucan, in greater than 200 milligrams per day with Jakafi. If you need to take fluconazole, you may need a dosage adjustment of Jakafi.

Other medications that can interact with Jakafi include:

Nizoral (ketoconazole)
Ery-Tab, Eryped, Erythrocin, among other brand names (erythromycin)
Rifadin, Rimactane (rifampin)
Cardizem, Dilacor XR, Dilt-CD, Matzim LA, Taztia XT, Tiazac, among other brand names (diltiazem)
Cordarone, Pacerone (amiodarone)

What Medications Are Similar?

Jakafi is not the only JAK inhibitor available. Other medications that inhibit JAK are available for myelofibrosis, some skin disorders, and rheumatoid arthritis. These medications include:

Vonjo (Pacritinib): Vonjo is used for people with intermediate or high-risk myelofibrosis with platelet counts less than 50.
Inrebic (Fedratinib): Inrebic is used for adults with intermediate or high-risk primary or secondary myelofibrosis.
Xeljanz (tofacitinib): This JAK inhibitor can be used for rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ulcerative colitis.

Frequently Asked Questions

What is Jakafi used for?

Jakafi is used for certain types of blood disorders, called myelofibrosis and polycythemia vera. It can also be used for acute and chronic graft-versus-host disease, which hasn’t responded to other treatments.
How does Jakafi work?

Jakafi works by blocking the JAK protein signal. This protein signal is one of the signals responsible for the overproduction of blood cells and causes of inflammation. When this signal is blocked, it can’t get through to continue the abnormal process.
How do I stop taking Jakafi?

Never abruptly stop taking Jakafi unless specifically instructed by your healthcare provider. Stopping too quickly may cause changes in blood counts. Some people need to taper off the medication slowly.

How Can I Stay Healthy While Taking Jakafi?

It is important to remember that Jakafi is meant to be taken long-term, so it’s vital to notify your healthcare provider of any side effects that you may be experiencing. Be sure to keep follow-ups with your healthcare team and continue to get labs drawn as ordered. Your healthcare provider may want to measure your blood counts regularly to determine the best dose for you.

You should not stop taking Jakafi suddenly. Speak to your healthcare team about any questions or potential tapering of your dose.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

5 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Food and Drug Administration. Jakafi label.
Tegtmeyer K, Ravi M, Zhao J, Maloney NJ, Lio PA. Off-label studies on the use of ruxolitinib in dermatology. Dermatitis. 2021;32(3):164-172.
Food and Drug Administration. Vonjo label.
Food and Drug Administration. Inrebic label.
Food and Drug Administration. Xeljanz label.

By Julie Scott, MSN, ANP-BC, AOCNP
Julie is an Adult Nurse Practitioner with oncology certification and a healthcare freelance writer with an interest in educating patients and the healthcare community.

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Jakafi (Ruxolitinib)- Oral