Unexpected side effect in mCRC: A care-compliant case report of regorafenib-induced hyperammonemic encephalopathy

Michela Quirino, Sabrina Rossi, Giovanni Schinzari, Michele Basso, Antonia Strippoli, Alessandra Cassano, Carlo Barone

Research output: Contribution to journalArticlepeer-review


Rationale: Regorafenib represents a treatment option in heavily pretreated patients affected by metastatic colorectal cancer (mCRC). Its safety profile is typical of small-molecule tyrosine-kinase inhibitors (TKIs) and most adverse events are manageable. Patientconcerns:A 56 years-old Caucasian man affected by mCRC with normal hepatic reserve was treated with regorafenib as second-line treatment. After only 2 days of therapy, the patient presented to the emergency department due to impairment of both spatial and temporal orientation and motor function with bradylalia. Interventions: Serum ammonia level was 191mmol/L, liver function tests and complete blood count were normal. Regorafenib was withheld and branched chain amino acids and lactulose were administered. Outcomes: Serum ammonia level returned within the normal range, but when regorafenib was restarted at a lower dose level, a new episode of acute confusion arised. Main lesson: Discontinuation of regorafenib after confirmation of hyperammonemia is strongly recommended; reintroduction of the therapy at lower doses after resolution of symptoms related to hyperammonemic encephalopathy has to be discouraged.

Original languageEnglish
Article numbere6522
JournalMedicine (United States)
Issue number16
Publication statusPublished - Jan 1 2017


  • Case report
  • Hyperammonemic encephalopathy
  • Regorafenib
  • TKI

ASJC Scopus subject areas

  • Medicine(all)


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