NCIt definition : 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.;