Paralytic ileus, a new rare toxicity of capecitabine: Two case reports

Paralytic ileus (or adynamic ileus) refers to a lack of passage of intestinal contents due to disturbances of normal intestinal motility, in absense of mechanical obstruction. The most common causes are intra-abdominal surgery, severe metabolic problems, drugs. We present two clinical cases related to patients with breast cancer and admitted with paralytic ileus following treatment with capacitabine in local Lanciano Hospital. Naranjo, Jones algoritms suggest a direct causal relationship. Our two cases, to our knowledge, represent the first published report of this particular intestinal toxicity of capecitabine. Pathophisiological explanation is difficult because no data are known about fluoropyrimidines effects on enteric motor functions (motor system, neural influences, hormonal factors): Tegafur (UFT) also, another oral fluoropyrimidine, induces paralytic ileus. We hypothesize that some 5-flourouracil metabolites (5-fluorocitrate; fluoro-beta-alanine), seldom responsible for central and peripherical neurotoxicity from fluoropyrimidines, can sometimes cause a neuropathy, and so a paralytic ileus. Paralytic ileus is probably a rare complication of capecitabine, but the oncologist should take it into careful consideration, because of his possible seriousness and because a suitable management of early signs of abdominal distension (with nasogastric suction and/or rectal tube, i.v. infusion of fluids and electrolytes, etc.) can avoid a unnecessary operative treatment.