Abstract
Capecitabine is prodrug of 5 FU (5-fluorouracil). Owing to the drug's tumor-specific conversion to its active form, it is currently widely used for various cancers. It has a very different toxicity profile, hand-foot syndrome is the most frequent dermatologic side effect of capecitabine therapy, while SJS is the least common manifestation. A female who is 35 years old, has been diagnosed with left breast cancer with metastasis to the bones and lymph nodes. After eight days of treatment with capecitabine, she developed abdominal distension and loose stool, burning micturition, and fever with mucocutaneous lesions. The patient showed clinical symptoms consistent with SJS, which was verified by a dermatology consultation. Based on assessments using the Naranjo, WHO-UMC, and Hartwig’s scale, the reaction was determined to be both possible and severe. The patient received both pharmacological and supportive care interventions. During a hospital stay, the patient gradually improved and was discharged with stable hemodynamics. The serious and potentially fatal hypersensitivity reactions that can result from capecitabine are highlighted in this case report. Healthcare professionals need to be aware of the uncommon side effects of chemotherapy, such as early symptom detection and management, which can enhance the safety of anti-cancer medications

Key words: Steven–Johnson syndrome, capecitabine