Abstract
Calcium polycarbophil has been found to be useful in the treatment of irritable bowel syndrome. It is activated through transformation to polycarbophil by decalcification under the acidic conditions in the stomach. Polycarbophil absorbs water in the small intestine, where conditions are neutral, causing it to swell and form a gel.
We encountered a patient in whom calcium polycarbophil was effective when given alone but developed diarrhea when it was administered together with lithium carbonate. When these two agents were taken separately, the diarrhea was relieved. In order to ascertain how lithium carbonate affected calcium polycarbophil, we carried out an in vitro experiment whose results showed that lithium carbonate caused an increase in pH. This inhibited decalcification, and reduced the extent of swelling of polycarbophil. These results suggest that the efficacy of calcium polycarbophil would be reduced when administered together with lithium carbonate.
