Dizziness, diarrhea, headache, weight gain, or gas may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
People using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.
Tell your doctor right away if you have any serious side effects, including: unusual tiredness, easy bleeding/bruising, unusual skin changes.
This medication may lower your ability to fight infections. This may make you more likely to get a serious (rarely fatal) infection or make any infection you have worse. Tell your doctor right away if you have any signs of infection (such as fever, chills, cough, painful skin rash/blisters, persistent sore throat).
This medication may also increase your risk of getting a rare but very serious (sometimes fatal) brain infection (progressive multifocal leukoencephalopathy-PML). Get medical help right away if any of these rare but very serious side effects occur: clumsiness, loss of coordination, weakness, sudden change in your thinking (such as confusion, difficulty concentrating), difficulty moving your muscles, problems with speech, seizure, vision changes.
Another medication similar to ruxolitinib has caused serious (possibly fatal) side effects, including heart problems, blood clots, and cancer (such as lymphoma). Before using ruxolitinib, tell your doctor or pharmacist if you have a history of heart disease, stroke, cancer, or any risk factors for heart disease (such as high blood pressure, diabetes, previous blood clots, high cholesterol, smoking or history of smoking). Discuss the risks and benefits of treatment with your doctor. Get medical help right away if you have symptoms such as shortness of breath/rapid breathing, chest/jaw/left arm pain, unusual sweating, sudden dizziness/fainting, pain/swelling/warmth in the groin/calf, sudden/severe headaches, trouble speaking, or weakness on one side of the body.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.