Ruxolitinib: uses, dosing, side effects & brands
Ruxolitinib is a janus kinase inhibitor sold in the U.S. under 3 brand and generic names, for polycythemia vera and primary myelofibrosis. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Janus Kinase Inhibitor
- Treats (across its forms)
- Polycythemia Vera and Primary Myelofibrosis
- Available as
- Tablet · Tablet, extended release · Topical
- Sold as
- 3 products — Jakafi, Jakafi XR and Opzelura
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
- Boxed warning
- Boxed warning
How Jakafi is dosed
From the FDA label for Jakafi (application NDA202192). Other ruxolitinib products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Doses should be individualized based on safety and efficacy. Starting doses per indication are noted below. Myelofibrosis ( 2.2 ) The starting dose of JAKAFI/JAKAFI XR is based on patient’s baseline platelet count: • Greater than 200 × 10 9 /L: JAKAFI 20 mg given orally twice daily or JAKAFI XR 44 mg given orally once daily. • 100 x 10 9 /L to 200 x 10 9 /L: JAKAFI 15 mg given orally twice daily or JAKAFI XR 33 mg given orally once daily. • 50 x 10 9 /L to less than 100 x 10 9 /L: JAKAFI 5 mg given orally twice daily or JAKAFI XR 11 mg given orally once daily. Polycythemia Vera ( 2.3 ) The starting dose of JAKAFI is 10 mg given orally twice daily or JAKAFI XR 22 mg given orally once daily. Acute Graft-Versus-Host Disease ( 2.4 ) The starting dose of JAKAFI is 5 mg given orally twice daily or JAKAFI XR 11 mg given orally once daily. Chronic Graft-Versus-Host Disease ( 2.5 ) The starting dose of JAKAFI is 10 mg given orally twice daily or JAKAFI XR 22 mg given orally once daily. 2.1 Monitoring to Assess Safety Prior to JAKAFI/JAKAFI XR treatment: Perform a complete blood count (CBC) [see Warnings and Precautions ( 5.1 )] . Inquire about past infections, including tuberculosis, herpes simplex, herpes zoster, and hepatitis B [see Warnings and Precautions ( 5.2 )] . During treatment with JAKAFI/JAKAFI XR : Perform a CBC every 2 to 4 weeks until doses are stabilized, and then as…
Everything below is the FDA label for Jakafi (tablet). Ruxolitinib is also sold as tablet, extended release and topical, and those are different medicines to take — follow the label for the one you were prescribed.
Jakafi side effects
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. The most common nonhematologic adverse…
Who shouldn’t take Jakafi
None. None. ( 4 )
Jakafi drug interactions
Fluconazole: Avoid concomitant use with fluconazole doses greater than 200 mg. Reduce JAKAFI/JAKAFI XR dosage with fluconazole doses less than or equal to 200 mg. ( 2.6 , 7 ) Strong CYP3A4 Inhibitors: Reduce, interrupt, or discontinue JAKAFI/JAKAFI XR doses as recommended except in patients with acute or chronic graft-versus-host-disease. ( 2.6 , 7 ) 7.1 Effect of Other Drugs on JAKAFI/JAKAFI XR Fluconazole Concomitant use of JAKAFI/JAKAFI XR with fluconazole increases ruxolitinib exposure [ see Clinical Pharmacology ( 12.3 )] , which may increase the risk of exposure-related adverse reactions. Avoid concomitant use of JAKAFI/JAKAFI XR with fluconazole doses of greater than 200 mg daily. Reduce the JAKAFI/JAKAFI XR dosage when used concomitantly with fluconazole doses of less than or equal to 200 mg [ see Dosage and Administration ( 2.6 )] . Strong CYP3A4 Inhibitors Concomitant use of JAKAFI/JAKAFI XR with strong CYP3A4 inhibitors increases ruxolitinib exposure [ see Clinical Pharmacology ( 12.3 )] , which may increase the risk of exposure-related adverse reactions. Reduce the JAKAFI/JAKAFI XR dosage when used concomitantly with strong CYP3A4 inhibitors except in patients with aGVHD or cGVHD [ see Dosage and Administration ( 2.6 )] . Strong CYP3A4 Inducers Concomitant use of JAKAFI/JAKAFI XR with strong CYP3A4 inducers may decrease ruxolitinib exposure [ see Clinical Pharmacology ( 12.3 )] , which may reduce efficacy of JAKAFI/JAKAFI XR. Monitor patients frequently and adjust the JAKAFI/JAKAFI XR dose based on safety and efficacy [ see Clinical Pharmacology ( 12.3 )] .
Every ruxolitinib product we track (3)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | Not yet rated | Prescription | Tablet | No data | — | View → | |
| 2 | Not yet rated | Prescription | Tablet | No data | — | View → | |
| 3 | Not yet rated | Prescription | Topical | No data | — | View → |
Ruxolitinib and breastfeeding
From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.
Full LactMed record for ruxolitinib: levels in milk, effects in breastfed infants, and the drugs it would consider insteadNo information is available on the clinical use of ruxolitinib during breastfeeding. Because ruxolitinib is 97% bound to plasma proteins, the amount in milk is likely to be low. The manufacturer recommends that breastfeeding be discontinued during ruxolitinib therapy and for 2 weeks after the last dose for the oral tablets and for 4 weeks after the last dose for the topical cream. However, ruxolitinib cream is approved for direct application in children as young as 2 years of age.
National Institute of Child Health and Human Development, record revised December 15, 2025. LactMed states its information is not a substitute for professional judgement.
What people report to the FDA about ruxolitinib
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 278 reports naming ruxolitinib, and the FDA flagged 94% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- sepsis45 reports
- multiple organ dysfunction syndrome34 reports
- treatment failure34 reports
- acute graft versus host disease33 reports
- adenovirus infection32 reports
- stenotrophomonas infection31 reports
- thrombocytopenia22 reports
- neutropenia20 reports
Read these as a signal, not a rate. A report does not mean ruxolitinib caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label.
Source: openFDA drug/event (FAERS), retrieved September 26, 2026.
Related calculators
Frequently asked questions
What is Jakafi?
Jakafi (Ruxolitinib Phosphate) is a janus kinase inhibitor used to treat Polycythemia Vera, Primary Myelofibrosis.
What kind of drug is ruxolitinib?
The FDA classifies ruxolitinib as a janus kinase inhibitor. JAK inhibitors block Janus kinase enzymes inside immune cells. These enzymes normally pass along messages from inflammatory signals (cytokines) to relay proteins that switch on genes, so blocking them turns down the overactive immune signaling that drives diseases like rheumatoid arthritis. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take ruxolitinib with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run ruxolitinib against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is ruxolitinib sold under?
We track 3 ruxolitinib-containing products in the U.S.: Jakafi, Jakafi XR and Opzelura. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does ruxolitinib come in?
Across the brands we track, ruxolitinib is currently marketed as tablet, tablet, extended release and topical, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic ruxolitinib?
We do not currently list a generic-labelled ruxolitinib product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Ruxolitinib: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/ruxolitinib
- MLA
- “Ruxolitinib: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/ruxolitinib.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for ruxolitinib on DailyMed (NIH) ↗ — including its boxed warning in full.