2020 Volume 46 Issue 10 Pages 600-605
In recent years, there has been an increasing number of cases in which anti-cancer drug treatment is performed for patients with reduced physiological functions such as elderly patients and those undergoing maintenance hemodialysis. In systemic chemotherapy for esophageal cancer, a regimen containing 5-fluorouracil (5-FU)has been established as a standard treatment, but a rare side effect is hyperammonemia with impaired unconsciousness. 5-FU is mainly metabolized by liver dihydropyrimidine dehydrogenase (DPD), whereas the catabolic metabolite alpha-fluoro-beta-alanine (FBAL) is excreted in urine. Therefore administration of 5-FU under certain conditions, such as for severe renal dysfunction or to patients undergoing maintenance hemodialysis, may increase FBAL plasma levels and cause hyperammonemia. When FP treatment was administered to patients undergoing maintenance hemodialysis at Kitano Hospital, the plasma ammonia level was high at 1,325 μg/dL and FBAL was high at 33.63 μg/mL on the fourth day. An increase in FBAL may be a cause of hyperammonemia. In patients with reduced renal function or dialysis patients, 5-FU dose reduction should be considered and regular monitoring of ammonia is required.
