Oculomotor disturbances associated with 5-fluorouracil chemotherapy

Two patients treated with 5-fluorouracil (5-FU) for disseminated adenocarcinoma of the colon developed cerebellar dysfunction typical of 5-FU neurotoxicity. The neurotoxicity was associated with oculomotor disturbances expressed primarily as weakness of convergence and divergence. Detailed postmortem examination of one patient revealed no anatomical abnormalities of the central nervous system. The ocular motor disturbances are probably an expression of regional 5-FU neurotoxicity primarily affecting the brain stem.