# The oncology nurse reviews a call after the first fluorouracil infusion. Which findings require immediate follow-up? Highlight the findings associated with acute early or unusually severe toxicity. > source: MyMerci (mymerci.kr) > url: https://mymerci.kr/pages/nclex_q.php?qn_id=495940&lang=en > language: en > subject: Medication Administration > category: PPT ## Question The oncology nurse reviews a call after the first fluorouracil infusion. Which findings require immediate follow-up? Highlight the findings associated with acute early or unusually severe toxicity. Nurses' Notes 0910: The oncology nurse calls a client on treatment day 4 after the first fluorouracil infusion. The client reports that watery diarrhea occurred 8 times since midnight. The client denies blood in the stool but feels weak when standing. The nurse learns that mild nausea improved after the prescribed antiemetic. The client states that painful mouth ulcers now prevent drinking fluids. Oral intake has fallen to a few small sips since yesterday evening. The client reports that urine remains pale yellow without burning. A family member says that the client slept for 7 hours overnight. At 0920, the client has new confusion and difficulty walking across the room. The family member denies any fall or sedating medication use. The client states that the infusion-site skin remains intact without redness. The temperature is 37.2 °C, and the client can speak in complete sentences. The medication list shows that the prescribed oral rinse was used after meals. The record contains no pretreatment DPYD result because therapy was urgent. The nurse keeps the next dose on hold while contacting the oncology prescriber. ## Explanation Frequent watery diarrhea, mouth ulcers that prevent drinking, and new confusion with gait difficulty are severe early fluorouracil toxicities. Hold further treatment and obtain urgent oncology evaluation for possible DPD deficiency. ## In-depth explanation Quick answer Highlight 8 episodes of watery diarrhea, mouth ulcers that prevent fluid intake, and new confusion with difficulty walking. Their early, severe appearance after initial fluorouracil exposure is a high-risk toxicity pattern. Why this is correct Fluorouracil is normally broken down largely by dihydropyrimidine dehydrogenase, or DPD. Markedly reduced DPD activity can cause excessive exposure, so gastrointestinal lining injury and neurotoxicity may appear unusually early and become life-threatening. The label directs clinicians to withhold or discontinue treatment based on the onset and severity while the client receives urgent assessment and supportive care.[2] Easy analogy or mental picture Think of a drain that clears medicine from the body. If the drain is nearly closed, the medicine rises quickly and harms sensitive tissues such as the mouth, bowel, marrow, and nervous system. The drain picture explains accumulation but not an individual dose decision. Memory hook Early plus severe toxicity means stop and evaluate. NCLEX decision rule When severe diarrhea, mucositis, or neurologic change begins early in fluorouracil therapy, think excessive exposure and possible DPD deficiency; check hydration, blood counts, neurologic status, and the oncology plan before another dose. Why the other choices are wrong Mild nausea relieved by treatment, normal urine, ordinary sleep, an intact infusion site, and use of a prescribed rinse do not match the severe early toxicity pattern. They still belong in routine assessment but do not carry the same urgency.References - [1]NCSBN: 2026 NCLEX-RN Test PlanNational Council of State Boards of Nursing - [2]DailyMed: Fluorouracil Injection Prescribing InformationU.S. National Library of Medicine ## Related questions - [Before giving a scheduled dose of digoxin, the nurse obtains an apical pulse of 54/min in …](https://mymerci.kr/pages/nclex_q.php?qn_id=374883&lang=en) - [An older adult taking digoxin reports nausea, poor appetite, and yellow-green halos. 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