SPRYCEL may cause serious side effects, including low blood cell counts, bleeding problems, fluid retention, heart and blood vessel (cardiovascular) problems, pulmonary arterial hypertension, severe skin reactions, tumor lysis syndrome, slowing of growth and development in children, and liver problems. Side effects of SPRYCEL that are considered most common in adults and children receiving SPRYCEL alone include: diarrhea, headache, skin rash, shortness of breath, tiredness, nausea, and muscle pain. Side effects of SPRYCEL that are considered most common in children receiving SPRYCEL with chemotherapy include: swelling, pain and redness of the lining of your mouth, throat, stomach and bowel (mucositis), low white blood cell counts with fever, fever, diarrhea, nausea, vomiting, muscle pain, stomach-area (abdominal) pain, cough, headache, rash, tiredness, constipation, abnormal heart rate, high blood pressure (hypertension), swelling, infections, low blood pressure, decreased appetite, allergic reactions, shortness of breath, nose-bleed, numbness or tingling of your hands and feet, and feeling confused or disoriented.