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Selumetinib Side Effects

Medically reviewed by Last updated on Dec 12, 2023.

Applies to selumetinib: oral capsule.

Serious side effects of Selumetinib

Along with its needed effects, selumetinib may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking selumetinib:

More common

Less common

Other side effects of Selumetinib

Some side effects of selumetinib may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

For Healthcare Professionals

Applies to selumetinib: oral capsule.


The most common adverse reactions occurring in 40% of patients or greater included vomiting, rash (all types), abdominal pain, diarrhea, nausea, dry skin, fatigue, musculoskeletal pain, pyrexia, acneiform rash, stomatitis, headache, paronychia, and pruritus.[Ref]


Very common (10% or more): Decreased ejection fraction (up to 23%), sinus tachycardia (20%), increased blood pressure and hypertension (less than 20%)[Ref]


-The most common rashes included dermatitis acneiform (54%), maculopapular rash (39%), and eczema (28%).

-Rashes of all types included: Dermatitis acneiform, rash maculo-papular, erythema, rash pustular, rash, urticaria, exfoliative rash, rash pruritic, rash erythematous

-Rash acneiform included: Dermatitis acneiform

-Dermatitis included: Dermatitis atopic, dermatitis diaper, eczema, seborrheic dermatitis, skin irritation

-Hair changes included: Alopecia, hair color change

-Skin infections included: Abscess, cellulitis, impetigo, and staphylococcal skin infection[Ref]

Very common (10% or more): Rash, all types (up to 91%), dry skin (60%), rash acneiform (50%), paronychia including nail infection (48%), pruritus (46%), dermatitis (36%), hair changes (32%), skin infections (20%)

Frequency not reported (events from other studies): Palmar-plantar erythrodysesthesia syndrome[Ref]


Very common (10% or more): Vomiting (82%), abdominal pain (76%), diarrhea (up to 77%), nausea (up to 73%), stomatitis including mouth ulceration (50%), constipation (34%), increased lipase (32%), dry mouth (less than 20%), increased amylase (18%)

Frequency not reported (events from other studies): Perforation, colitis, ileus, intestinal obstruction[Ref]


Very common (10% or more): Decreased albumin (51%), decreased hemoglobin (41%), decreased neutrophils (33%), decreased lymphocytes (20%)[Ref]


Very common (10% or more): Increased AST (41%), increased ALT (35%)[Ref]


Very common (10% or more): Increased potassium (27%), decreased appetite (22%), weight increased (less than 20%), decreased potassium (18%), increased alkaline phosphatase (18%), increased sodium (18%), decreased sodium (16%)[Ref]


Very common (10% or more): Increased creatine phosphokinase (up to 79%), musculoskeletal pain including extremity, back, and neck pain (58%)

Frequency not reported (events from other studies): Rhabdomyolysis[Ref]

Nervous system

Very common (10% or more): Headache (48%)[Ref]


Very common (10% or more): Visual impairment including blurred vision, photophobia, cataracts, and ocular hypertension (less than 20%)

Uncommon events reported in other studies (0.1% to 1%): Retinal vein occlusion (RVO), retinal pigment epithelial detachment (RPED), central serous retinopathy (CSR)[Ref]


Very common (10% or more): Fatigue and malaise/asthenia (56%), pyrexia (56%), general and localized edema including peripheral swelling (20%), facial and periorbital edema (less than 20%)[Ref]


Very common (10% or more): Epistaxis (28%), dyspnea including exertional and at rest (less than 20%)[Ref]


Very common (10% or more): Hematuria (22%), proteinuria (22%), acute kidney injury (less than 20%)


1. Product Information. Koselugo (selumetinib). Astra-Zeneca Pharmaceuticals. 2020.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.