What the label lists and what reports show

Ruxolitinib side effects

Ruxolitinib's FDA label: “In myelofibrosis and polycythemia vera, the most common hematologic adverse reactions (incidence > 20%) are thrombocytopenia and anemia.” FAERS holds 71,241 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is fatigue (6,114 reports).

No generic listed

Check it at the source: the ruxolitinib FDA label on DailyMed (effective July 20, 2026, Incyte Corporation); the FDA FAERS public dashboard.

What does the patient leaflet say about side effects?

From the patient leaflet: What are the possible side effects of JAKAFI or JAKAFI XR?
JAKAFI or JAKAFI XR can cause serious side effects including: • Low blood cell counts. JAKAFI or JAKAFI XR can cause low platelet counts (thrombocytopenia), low red blood cell counts (anemia), and low white blood cell counts (neutropenia). If you develop bleeding, stop JAKAFI or JAKAFI XR and call your healthcare provider. Your healthcare provider will do a blood test to check your blood cell counts before you start JAKAFI or JAKAFI XR and regularly during your treatment with JAKAFI or JAKAFI XR. 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 or JAKAFI XR. […]

Source: FDA drug label, Incyte Corporation, effective July 20, 2026 (SPL set f1c82580-87ae-11e0-bc84-0002a5d5c51b), via openFDA; the full label on DailyMed

What does the label list?

From the label: adverse reactions
In myelofibrosis and polycythemia vera, the most common hematologic adverse reactions (incidence > 20%) are thrombocytopenia and anemia.

Table 19: Acute Graft-Versus-Host Disease: Nonhematologic Adverse Reactions Occurring in ≥ 15% of Patients in the Open-Label, Single Cohort Study

Reaction	All Grades National Cancer Institute Common Terminology Criteria for Adverse Events…	JAKAFI (N = 71) Grade 3-4 (%)
Infections (pathogen not specified)	55	41
Edema	51	13
Hemorrhage	49	20
Fatigue	37	14
Bacterial infections	32	28
Dyspnea	32	7
Viral infections	31	14
Thrombosis	25	11
Diarrhea	24	7
Rash	23	3
Headache	21	4
Hypertension	20	13
Dizziness	16	0

Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.

From the label: adverse reactions, continued
The following clinically significant adverse reactions are discussed in greater detail in other sections of the labeling: Thrombocytopenia, Anemia and Neutropenia [see Warnings and Precautions ( 5.1 )] Risk of Infection [see Warnings and Precautions ( 5.2 )] Symptom Exacerbation Following Interruption or Discontinuation of Treatment [see Warnings and Precautions ( 5.3 )] Non-Melanoma Skin Cancer [see Warnings and Precautions ( 5.4 )] Lipid Elevations [ see Warnings and Precautions ( 5.5 )] Major Adverse Cardiovascular Events (MACE) [ see Warnings and Precautions ( 5.6 )] Thrombosis [ see Warnings and Precautions ( 5.7 )] Secondary Malignancies [ see Warnings and Precautions ( 5.8 )] In myelofibrosis and polycythemia vera, the most common hematologic adverse reactions (incidence > 20%) are thrombocytopenia and anemia. The most common nonhematologic adverse reactions (incidence ≥ 15%) are bruising, dizziness, headache, and diarrhea. ( 6.1 ) In acute graft-versus-host disease, the most common hematologic adverse reactions (incidence > 50%) are anemia, thrombocytopenia, and neutropenia. The most common nonhematologic adverse reactions (incidence > 50%) are infections (pathogen not specified) and edema. ( 6.1 ) In chronic graft-versus-host disease, the most common hematologic adverse reactions (incidence > 35%) are anemia and thrombocytopenia. …

Source: FDA drug label, Incyte Corporation, effective July 20, 2026 (SPL set f1c82580-87ae-11e0-bc84-0002a5d5c51b), via openFDA; the full label on DailyMed

What do FAERS reports show?

71,241 reports list ruxolitinib among the medicines taken, each a report of something that happened, not proof the medicine caused it; 9,813 are coded as a death and 13,602 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 21 reactions below, 10 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.

Reports received each year

The 25 most reported reactions

Off Label Use (a use or a product term, not a reaction)14,560
Death (an outcome recorded in the report)6,393
Fatigue (named in the label)6,114
Anaemia (named in the label)3,094
Haemoglobin Decreased2,961
Platelet Count Decreased2,700
Diarrhoea (named in the label)2,683
Product Dose Omission Issue (a use or a product term, not a reaction)2,653
Asthenia2,531
Dizziness (named in the label)2,494
Headache (named in the label)2,425
Product Availability Issue2,331
Drug Ineffective (a use or a product term, not a reaction)2,172
Pneumonia2,170
Nausea (named in the label)2,155
Weight Increased (named in the label)1,996
Dyspnoea (named in the label)1,987
Pain1,856
Pruritus1,808
Splenomegaly1,764
Malaise1,601
Pyrexia (named in the label)1,549
Platelet Count Increased1,536
Fall1,516
Contusion (named in the label)1,508

Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms

What next?

Ruxolitinib: the full record: label, generics, price, shortages, recalls
Report a side effect to the FDA: MedWatch
Side effects hub: the most reported medicines and reactions