The adverse effects of irinotecan, such as myelosuppression and diarrhoea, would be expected to be exacerbated by other antineoplastic agents having similar adverse effects.
Patients who have previously received pelvic/abdominal irradiation are at increased risk of severe myelosuppression following the administration of irinotecan. The concurrent administration of irinotecan with irradiation has not been adequately studied and is not recommended.
Lymphocytopenia has been reported in patients receiving irinotecan and it is possible that the administration of dexamethasone as antiemetic prophylaxis may have enhanced the likelihood of this effect. However, serious opportunistic infections have not been observed, and no complications have specifically been attributed to lymphocytopenia. Hyperglycemia has also been reported in patients receiving irinotecan. Usually, this has been observed in patients with history of diabetes mellitus or evidence of glucose intolerance prior to administration of irinotecan. It is probable that dexamethasone, given as antiemetic prophylaxis, contributed to hyperglycemia in some patients.
Drug-Laboratory Test Interactions: There are no known interactions between irinotecan and laboratory test.