Dysarthria induced by irinotecan in a patient with colorectal cancer

Abstract

Successful management and subsequent prevention of a rare adverse drug reaction (ADR) associated with irinotecan chemotherapy are reported. A 49-year-old man with meta-static colon cancer undergoing treatment with i.v. irinotecan (180 mg/m(2) to be infused over 120 minutes) as part of a multidrug chemotherapy regimen developed dysarthria about 90 minutes into irinotecan infusions on two occasions. In both instances, the dysarthric symptoms (numbness of the tongue and difficult speech) resolved after the discontinuation of irinotecan and administration of hydration therapy. Brain imaging studies showed no functional or structural abnormalities; several concomitantly administered medications, including metoclopramide, palonosetron, and other components of the chemotherapy regimen, were deemed unlikely to have played a causal or contributory role in the episodes of dysarthria. Application of the ADR probability scale of Naranjo et al. in this case yielded a score of 9, indicating a definite ADR caused by irinotecan. For subsequently administered chemotherapy cycles, the duration of the patient's irinotecan infusions was increased (to 180 minutes for cycles 3-5 and to 240 minutes for cycles 6-12). Dysarthria did not recur and, with the exception of transient tongue twisting during two of the 180-minute infusions, he completed the full course of irinotecan therapy without a recurrence of dysarthric symptoms. Irinotecan-induced dysarthria in a man being treated for colon cancer resolved with the discontinuation of irinotecan. With increases in the duration of infusion, the man received additional irinotecan treatments with no recurrence of dysarthria.