crofelemer

An oligomeric proanthocyanidin extracted from the latex produced by the tree Croton lechleri (Euphorbiaceae), with antidiarrheal, and potential antiviral and antimicrobial activities. Upon oral administration, crofelemer acts locally within the gastrointestinal (GI) tract by inhibiting both the cystic fibrosis transmembrane conductance regulator (CFTR) chloride ion (Cl-) channel and the calcium-activated Cl- channel (CaCC) expressed on the luminal surface of enterocytes. This inhibits the secretion of chloride ions into the intestinal lumen and prevents high volume water loss. By normalizing Cl- and water balance in the intestines, crofelemer relieves secretory diarrhea.