Selumetinib: uses, dosing, side effects & brands
Selumetinib is a kinase inhibitor sold in the U.S. under one brand, for neurofibromatosis 1. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Kinase Inhibitor
- Treats (across its forms)
- Neurofibromatosis 1
- Available as
- Capsule · Powder
- Sold as
- Koselugo
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
How selumetinib is dosed
From the FDA label for Koselugo (application NDA213756). Other selumetinib products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
KOSELUGO capsules: The recommended dosage is 25 mg/m 2 , swallowed whole, taken orally twice daily with or without food (see Table 1) . (2.1 , 2.2 ) • KOSELUGO oral granules: The recommended dosage is equivalent to 25 mg/m 2 , sprinkled onto or mixed with soft food and taken orally twice daily (see Table 2). ( 2.1 , 2.2 ) • Moderate hepatic impairment (Child-Pugh B): The recommended dosage is 20 mg/m 2 orally twice daily (see Tables 6 and 7) . ( 2.2 , 2.4 ) • Severe hepatic impairment (Child-Pugh C): The recommended dosage has not been established. ( 2.4 , 8.6 ) • Strong or Moderate CYP3A4 Inhibitors or Fluconazole: If coadministration with strong or moderate CYP3A4 inhibitors or fluconazole cannot be avoided, reduce the dose of KOSELUGO (see Tables 8 and 9) . ( 2.5 ) 2.1 Recommended Dosage The recommended dosage of KOSELUGO capsules ( see Table 1 ) and KOSELUGO oral granules ( see Table 2 ) for adult and pediatric patients 1 year of age and older, based on body surface area, is 25 mg/m 2 orally twice daily, until disease progression or unacceptable toxicity [see Dosage and Administration (2.2)]. Table 1 Recommended Dosage: KOSELUGO Capsules Body Surface Area The recommended dosage of KOSELUGO capsules for patients with a BSA less than 0.55 m 2 has not been established. KOSELUGO Capsules 0.55 – 0.69 m 2 20 mg in the morning and 10 mg in the evening 0.70 – 0.89 m 2 20 mg twice…
Selumetinib side effects
The following clinically significant adverse reactions are described elsewhere in the labeling: • Left Ventricular Dysfunction [see Warnings and Precautions (5.1) ] • Ocular Toxicity [see Warnings and Precautions (5.2) ] • Gastrointestinal Toxicity [see Warnings and Precautions (5.3) ] • Skin Toxicity [see Warnings and Precautions (5.4) ] • Increased Creatine Phosphokinase [see Warnings and Precautions (5.5) ] Most common adverse reactions in pediatric patients (≥ 40%) are: vomiting, diarrhea, increased creatine phosphokinase, dry skin, paronychia, nausea, dermatitis acneiform, and pyrexia. ( 6.1 ) Most common adverse reactions in adult patients (≥ 40%) are rash (all), dermatitis acneiform, and diarrhea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact AstraZeneca 1-800-236-9933 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The NF1 PN pediatric safety pool described in the WARNINGS AND PRECAUTIONS reflects exposure to KOSELUGO at the recommended dosage in 134 pediatric patients in SPRINKLE (N = 36) (NCT05309668), SPRINT Phase I (N = 24) (NCT01362803), SPRINT Phase II Stratum 1…
Who shouldn’t take selumetinib
None. None. ( 4 )
Selumetinib drug interactions
Strong or Moderate CYP3A4 Inhibitors or Fluconazole : Avoid coadministration of strong or moderate CYP3A4 inhibitors or fluconazole with KOSELUGO. If coadministration cannot be avoided, reduce the dose of KOSELUGO. ( 2.5 , 7.1 ) • Strong or Moderate CYP3A4 Inducers : Avoid concomitant use of strong and moderate CYP3A4 inducers. ( 7.1 ) 7.1 Effect of Other Drugs on KOSELUGO Strong or Moderate CYP3A4 Inhibitors or Fluconazole Management • Avoid concomitant use of strong or moderate CYP3A4 inhibitors or fluconazole with KOSELUGO. If coadministration with strong or moderate CYP3A4 inhibitors or fluconazole cannot be avoided, reduce KOSELUGO dosage [see Dosage Modifications for Drug Interactions (2.5) ]. Clinical Impact • Concomitant use of KOSELUGO with a strong or moderate CYP3A4 inhibitor or fluconazole increased selumetinib plasma concentrations [see Clinical Pharmacology (12.3) ] , which may increase the risk of adverse reactions. Strong or Moderate CYP3A4 Inducers Management • Avoid concomitant use of strong or moderate CYP3A4 inducers with KOSELUGO. Clinical Impact • Concomitant use of KOSELUGO with a strong or moderate CYP3A4 inducer decreased selumetinib plasma concentrations [see Clinical Pharmacology (12.3) ] , which may reduce KOSELUGO efficacy. Vitamin E Management • Supplemental vitamin E is not recommended if daily vitamin E intake (including the amount of vitamin E in KOSELUGO capsules and supplement) will exceed the recommended or safe limits. • Monitor for bleeding in patients administered a vitamin‑K antagonist or an anti‑platelet agent with KOSELUGO capsules. Increase INR monitoring, as appropriate, in patients taking a vitamin‑K antagonist [see Warnings and Precautions (5.3) ] . Clinical Impact • KOSELUGO capsules contain vitamin E and daily vitamin E intake that exceeds the recommended or safe limits may increase the risk of bleeding. An increased risk of bleeding may occur in patients taking a vitamin‑K antagonist or an anti‑platelet agent with KOSELUGO capsules.
Every selumetinib product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Koselugo.
Can you crush or split selumetinib?
At least one selumetinibproduct is labelled to be swallowed whole — crushing an extended-release tablet releases the whole day’s dose at once. Which applies depends on the form you were given.
What each selumetinib label says about crushing, splitting and chewingWhat people report to the FDA about selumetinib
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 3 reports naming selumetinib, and the FDA flagged 100% 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:
- aspartate aminotransferase increased1 reports
- blood creatine phosphokinase increased1 reports
- blood creatinine increased1 reports
- dehydration1 reports
- diarrhoea1 reports
- haemoglobin decreased1 reports
- hypoalbuminaemia1 reports
- hypotension1 reports
Read these as a signal, not a rate. A report does not mean selumetinib 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 section above.
Source: openFDA drug/event (FAERS), retrieved July 26, 2026.
Related calculators
Frequently asked questions
What is selumetinib?
Koselugo (Selumetinib Sulfate) is a kinase inhibitor used to treat Neurofibromatosis 1.
What kind of drug is selumetinib?
The FDA classifies selumetinib as a kinase inhibitor. Kinase inhibitors block protein kinases, the enzymes that relay 'grow and divide' signals inside cells. By shutting down the overactive kinase signals that a tumor depends on, they help slow or stop cancer cells from multiplying. 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 selumetinib 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 selumetinib against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does selumetinib come in?
Across the brands we track, selumetinib is currently marketed as capsule and powder, 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 selumetinib?
We do not currently list a generic-labelled selumetinib 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). Selumetinib: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/selumetinib
- MLA
- “Selumetinib: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/selumetinib.
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 selumetinib on DailyMed (NIH) ↗.