Retrospective Investigation of Constipation Occurrence in Case of Combined Use of Irinotecan Hydrochloride (CPT-11) and Hange-shashin-to and Relationship with CPT-11 Dose

The administration of Hange-shashin-to is effective in preventing diarrhea caused by irinotecan hydrochloride (CPT-11)when they are coadministered but a high incidence of constipation has been reported when CPT-11 is used in combination with anti-diarrhea drugs.As many aspects of the occurrence of constipation with the combined use of Hange-shashin-to and CPT-11 were unclear,we decided to clarify the occurrence of constipation and its relationship with the CPT-11 dosage.To do this,we retrospectively compared two treatment groups in which Hange-shashin-to had been coadministered with CPT11 at 60 mg/m2 and 48 mg/m2,respectively.The incidence of constipation was significantly higher in the group treated with CPT-11 at 60 mg/m2 and Hange-shashin-to than that treated with CPT-11 at 48 mg/m2.These results indicate that the occurrence of constipation in such combined use is correlated not only with the CPT-11 dose but also Hange-shashin-to activity.The results also suggest that interaction between Hange-shashin-to and CPT-11 is strongly associated with the occurrence of constipation.