Prevention of irinotecan-induced diarrhoea by oral carbonaceous adsorbent (Kremezin™) in cancer patients

Irinotecan (CPT-11) treatments induce severe diarrhoea at a rate of >40%. In clinical trials, we evaluated the preventing effects of oral alkalization, which has been reported previously, and oral carbonaceous adsorbent (Kremezin™) on diarrhoea possibly induced by CPT-11. Evaluation was made by counting the maximum number of bowel motions in each patient. Five patients out of 7 treated with CPT-11 had bowel motions of >5 times daily, and maximum number of bowel motions reached 20 times in 1 patient. Oral alkalization (2 g sodium bicarbonate, 2 g magnesium oxide and 300 mg ursodeoxycholic acid daily for 4 days) decreased bowel motions from 20 to 8 thereafter in the patient. Maximum number of bowel motions in other 3 patients treated in a combination of CPT-11 and oral alkalization was <3. Oral adsorbent (2 g Kremezin x 3 times, during and after CPT-11 treatment) also decreased maximum number of bowel motions from 7 (without oral adsorbent) to 3 in 1 patient. Also, the maximum number of bowel motions in other 3 patients treated with oral adsorbent was <3 (p<0.05, vs CPT-11 alone). Effect of oral Kremezin on plasma concentrations of CPT-11 and its related compounds after a 1-h CPT-11 infusion, evaluated in a patient, was small. These results suggested that the oral Kremezin is effective in ameliorating CPT-11-induced diarrhoea without decreasing much the plasma clearance of CPT-11.