Antidiarrhoeal agents and laxatives: changing concepts.

Recognition that altered intestinal electrolyte transport (decreased absorption and/or increased secretion) is a primary factor in many types of diarrhoea is shaping the search for new types of antidiarrhoeal agents; it also supports continuing interest in the time-honoured but still largely unproved adsorbents. Recognition that altered intestinal electrolyte transport is also a primary effect of certain of the laxatives is of less immediate practical significance, because of the appropriate emphasis on dietary fibre and other nonpharmacological measures for prevention and correction of functional constipation. However, interest in the laxatives and their mechanisms of action will probably be directed to unanswered problems in bowel motility and the pathogenesis of constipation, which could subsequently modify use of the laxatives.