Maeda, Y., Ohune, T., Nakamura, M., Yamasaki, M., Kiribayashi, Y., & Murakami, T. (2004). Prevention of irinotecan-induced diarrhoea by oral carbonaceous adsorbent (Kremezin) in cancer patients. Oncology Reports, 12(3), 581–585.

To examine the effectiveness of two interventions, AST-120 and oral alkalization, to ameliorate diarrhea after treatment with irinotecan

• Patients with varying cancers who were receiving irinotecan were given AST-120, oral alkalization, or nothing (control).
• AST-120 (Kremezin™) is an oral adsorbent made of activated carbon. Patients received 2 g at the start of irinotecan infusion, immediately after irinotecan infusion, and three hours after irinotecan infusion.
• Oral alkalization, consisting of 2 g NaHCO₃ (sodium bicarbonate), 2 g magnesium oxide, and 300 mg ursodexycholic acid, was given before irinotecan and then daily for three days after irinotecan administration.

The study reported on 13 Japanese patients with cancer receiving 60–100 mg/m² irinotecan every 1–2 weeks, alone or as part of a combination regimen. The control group consisted of 7 patients, the AST-120 group consisted of 4 patients, and the oral alkalization group consisted of 4 patients. One patient in each of the two intervention groups served as his or her own control, having received prior irinotecan with no prophylaxis.

This was a nonrandomized trial.

Patients recorded the number of bowel movements but not the volume.

• Oral alkalization appeared to be effective in ameliorating diarrhea, although the efficiency did not reach a significant difference (level of significance not indicated).
• AST-120 significantly decreased the maximum number of daily bowel movements during irinotecan treatments as compared with no prophylaxis (p < 0.05).

• This was a small study with only 13 patients.
• One patient in the AST-120 group and one patient in the oral alkalization group acted as his or her own control. Only three other patients were in each interventional treatment group.

Although further study is necessary regarding the effect of oral AST-120 on plasma concentrations of irinotecan-related compounds, it is speculated that the absorption of irinotecan or SN-38 from the intestinal lumen is small, if any, and the remaining irinotecan-related compounds in the intestinal lumen cause diffuse mucosal damage in irinotecan treatments.