Ruxolitinib

Ruxolitinib is a medication used to treat myeloproliferative neoplasms (MPNs). It is licensed for the treatment of patients with myelofibrosis (MF) either primary or occurring after polycythaemia vera (PV) or essential thrombocythaemia (ET). It is under investigation in clinical trials for patients with PV and ET. The drug is known by several names. It goes under the brand name Jakavi® and the molecule is called ruxolitinib, before this it was known as INC18424 or INC424.

How it works

Ruxolitinib works by interfering with the function of JAK2 and its relation JAK1. This slows down blood cell production and also the production of signalling chemicals known as cytokines.

When you take ruxolitinib the number of blood cells being made decreases so that your bloodstream will be less crowded, your blood will flow more freely, and you will be less likely to suffer a blood clot or thrombosis. Treatment with ruxolitinib also reduces the size of most patients’ spleens towards a more normal size. In addition, many of the symptoms of an MPN, for example sweating, itching, tiredness and pain and fullness after eating which with MF and other MPN patients suffer, improve with ruxolitinib therapy.

Are there any side effects?

Most people taking this drug tolerate it well and have few side effects.  However, it is important that you inform your doctor or nurse if you are experiencing any of the side effects listed below or develop any new symptoms, even if mild.

Common side effects

Approximately one person in 100 up to one person in five (1- 20%) of people taking ruxolitinib will experience some of these common side effects:

  • Reduced red blood cells. If your red blood cells drop too low (anaemia) you may notice that you are becoming breathless and tire easily.
  • Reduced platelets.  If your platelet count drops too low you may experience nose bleeds, bleeding gums when you clean your teeth, a rash of tiny red spots or increased bruising.
  • Reduced white blood cells.  If your white blood cells drop too low you may have an increased risk of developing infections. You may experience a high temperature, fever, shivers or chills.
If you experience any of the symptoms above you must contact your hospital immediately. Sudden and unexpected changes in blood cell levels may occur, although this is uncommon, therefore it is important to attend appointments to have your blood counts checked and to discuss any symptoms with your haematologist.

Other common side effects


  • Painful skin rash with blisters (possible symptoms of shingles (herpes zoster))
  • High level of cholesterol
  • Abnormal liver function test results
  • Dizziness
  • Headache
  • Weight gain
  • Frequently passing wind (flatulence)
If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed here.

Ruxolitinib and infections

Ruxolitinib treatment has been shown to be associated with increased risk of infections varying from simple chest and urine infections to reactivation or occurrence of more serious infections such as shingles, hepatitis, TB and rare infections including a disease called Progressive Multifocal Leucoencephalopathy.

Frequently asked questions

Can I eat and drink normally? Yes.  We recommend that you eat a normal, healthy diet and drink plenty of water.

Can I drink alcohol? While it is safe to drink alcohol in moderation whilst taking ruxolitinib, we recommend you do not exceed the recommended weekly limits of 21 units of alcohol per week for a man and 14 units for a woman. Alcohol can cause dehydration, and it is important to avoid becoming dehydrated if you have an MPN. Please ask your nurse or doctor if you require more information regarding alcohol consumption.

What if I want to have a child? We strongly recommend that you use contraception whilst taking ruxolitinib, because this medication can be harmful to a developing fetus. When planning to conceive or to father a child, you should stop taking ruxolitinib AFTER discussion with your doctor.

It is imperative to discuss your plans together with your haematologist prior to becoming pregnant or fathering a child. Your doctor can recommend treatment options for you that will not cause harm to your developing baby and will increase your chance of a successful pregnancy. If you or your partner becomes pregnant while taking this drug please contact your doctor immediately for further advice.

Can I breastfeed while taking ruxolitinib? Breastfeeding while taking ruxolitinib is not recommended.

Who will prescribe ruxolitinib for me? Your doctor, a specially trained nurse or hospital pharmacist will prescribe your medication.

Can I drive? There is no evidence that taking ruxolitinib would stop you from driving.

Do I need to take any special precautions? It is important not to stop taking ruxolitinib suddenly as this can cause a withdrawal type syndrome which consists of a return of symptoms and growth of your spleen which may be very sudden and have sometimes made patients very unwell.

Can I have vaccinations such as the flu jab while taking ruxolitinib? Yes, you can have most vaccinations including the flu vaccine whilst taking ruxolitinib. Some vaccinations are live vaccines and these should not be taken with ruxolitinib.  It is important you tell the person giving you the vaccine that you are taking ruxolitinib so they can verify it is safe for you to be vaccinated.

Interactions with other medicines and foods Ruxolitinib is metabolized through a pathway known as CYP3A4 so some drugs can increase or reduce its activity. A list of such drugs will be in the package insert or ask a pharmacist before taking any new medicine. This also extends to certain herbal remedies eg St John’s Wort and foodstuffs eg grapefruit and Seville oranges.

More information

If you would like more information you can download our leaflet, we can also send you a copy in the post if you prefer, please email info@mpnvoice.org.uk with your postal address.