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Tucatinib Side Effects

For the Consumer

Applies to tucatinib: oral tablet


Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • severe or ongoing diarrhea;

  • pain, blisters, bleeding, or severe rash in the palms of your hands or the soles of your feet;

  • blisters or ulcers in your mouth, red or swollen gums, trouble swallowing;

  • a seizure;

  • liver problems--loss of appetite, stomach pain (upper right side), tiredness, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

  • low red blood cells (anemia)--pale skin, unusual tiredness, feeling light-headed or short of breath, cold hands and feet.

Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.

Common side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to tucatinib: oral tablet


Very common (10% or more): Hemoglobin decreased (59%), decreased phosphate (57%), anemia (e.g., anemia, hemoglobin decreased, normocytic anemia) (21%)[Ref]


Very common (10% or more): Arthralgia (15%)[Ref]


Very common (10% or more): Anorexia (25%), weight loss (13%), magnesium decreased (40%), potassium decreased (36%), alkaline phosphate increased (26%)[Ref]


Very common (10% or more): Bilirubin increased (47%), ALT increased (46%), AST increased (43%), hepatotoxicity (e.g., hyperbilirubinemia, blood bilirubin increased, bilirubin conjugated increased, alanine aminotransferase increased, transaminases increased, hepatotoxicity, aspartate aminotransferase increased, liver function test increased, liver injury, hepatocellular injury) (42%)[Ref]


Very common (10% or more): Creatinine increased (33%)[Ref]


Very common (10% or more): Palmar-plantar erythrodysesthesia syndrome (63%), rash (e.g., rash maculopapular, rash, dermatitis acneiform, erythema, rash macular, rash papular, rash pustular, rash pruritic, rash erythematous, skin exfoliation, urticaria, dermatitis allergic, palmar erythema, plantar erythema, skin toxicity, dermatitis) (20%)[Ref]


Very common (10% or more): Diarrhea (81%), nausea (58%), vomiting (36%), stomatitis (e.g., stomatitis, oropharyngeal pain, oropharyngeal discomfort, mouth ulceration, oral pain, lip ulceration, glossodynia, tongue blistering, lip blister, oral dysesthesia, tongue ulceration, aphthous ulcer) (32%)[Ref]


1. "Product Information. Tukysa (tucatinib)." Seattle Genetics Inc, Bothell, WA.

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.

More about tucatinib

Consumer resources

Other brands: Tukysa

Professional resources

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