Ruxolitinib
Say it: rux-oh-LI-ti-nib · Brand names: Jakafi
Ruxolitinib is a targeted pill that calms overactive signals in the bone marrow and immune system.
What it is
Some bone marrow diseases are driven by overactive proteins called JAK1 and JAK2 (Janus kinases). Ruxolitinib blocks these proteins. This can shrink an enlarged spleen, lower blood counts that are too high, ease symptoms like night sweats and itching, and calm the immune attack in graft versus host disease.
Often used for
- myelofibrosis (scarring of the bone marrow)
- polycythemia vera (too many red blood cells)
- graft versus host disease after a stem cell transplant
How you get it
Ruxolitinib is a tablet you take by mouth twice a day. Many people take it for a long time. Your team may change the dose based on your blood counts. Your schedule may be different.
Common side effects and what helps
- Low platelets, which can cause easy bruising or bleeding. Your team will check your blood counts.
- Low red blood cells (anemia), which can make you tired or short of breath.
- Dizziness. Get up slowly.
- Headache. Ask your team what pain medicine is safe.
- Bruising. Use a soft toothbrush and an electric razor.
- Diarrhea. Drink plenty of fluids and tell your team if it does not get better.
- Weight gain or higher cholesterol. Your team may check your cholesterol.
Call your care team right away if you have
- A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher, or chills
- A painful blistering rash, which can be a sign of shingles
- Bleeding that will not stop, black or bloody stools, vomiting blood, or coughing up blood
- Chest pain, sudden weakness on one side, trouble speaking, or pain and swelling in one leg
- Confusion, trouble thinking, weakness on one side, or vision changes that get worse over days
- A cough that does not go away, night sweats and weight loss
Before you start, tell your team
- If you have an infection, or have had tuberculosis, hepatitis B or shingles
- If you have had heart disease, a stroke or blood clots, or if you smoke
- If you have had skin cancer
- If you have kidney or liver problems
- If you are pregnant, may become pregnant, or are breastfeeding
- All the medicines you take, including vitamins, herbs and supplements
Good to know
- You will have blood tests to check your blood counts, often every few weeks at first.
- Ruxolitinib raises the risk of serious infections, including shingles and tuberculosis. Your team may test you before starting.
- Do not stop it suddenly unless your team tells you to. Symptoms can come back quickly. Your team will guide you if it needs to be stopped.
- Medicines like this may raise the risk of heart problems, blood clots and some cancers, including skin cancer. Have your skin checked regularly.
At home
- Take it twice a day at about the same times, with or without food.
- If you miss a dose, ask your care team what to do. Do not take two doses to make up for it.
- Store at room temperature, away from children and pets.
- Do not run out. Ask for refills early so you do not miss doses.
Questions to ask
- How often will I need blood tests?
- What should I do if I get an infection?
- How will we know if it is working?
- What should I do if I need to stop it?
Side effect guides
- Fatigue (tiredness)
- Diarrhea
- Anemia (low red blood cells)
- Low platelets and bleeding
- Shortness of breath
- Pain
Sources
Quick answers
- What is Ruxolitinib?
- Ruxolitinib is a targeted pill that calms overactive signals in the bone marrow and immune system. Brand names: Jakafi.
- What is Ruxolitinib used for?
- myelofibrosis (scarring of the bone marrow); polycythemia vera (too many red blood cells); graft versus host disease after a stem cell transplant.
- How is Ruxolitinib given?
- Ruxolitinib is a tablet you take by mouth twice a day. Many people take it for a long time. Your team may change the dose based on your blood counts. Your schedule may be different.
- What are the common side effects of Ruxolitinib?
- Low platelets, which can cause easy bruising or bleeding. Low red blood cells (anemia), which can make you tired or short of breath. Dizziness. Headache. Bruising. Diarrhea. Weight gain or higher cholesterol.
- When should I call my care team while taking Ruxolitinib?
- A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher, or chills; A painful blistering rash, which can be a sign of shingles; Bleeding that will not stop, black or bloody stools, vomiting blood, or coughing up blood; Chest pain, sudden weakness on one side, trouble speaking, or pain and swelling in one leg; Confusion, trouble thinking, weakness on one side, or vision changes that get worse over days; A cough that does not go away, night sweats and weight loss.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.