The mechanism is selective for the CFTR and CaCC, as other channels involved in intestinal fluid secretion, namely sodium and potassium channels, are not affected by crofelemer, nor is cAMP or calcium signaling.Crofelemer is minimally, if at all, absorbed from the gut into the bloodstream, and is mostly excreted in the stools. Adverse effects and interactions
Crofelemer is well tolerated; and the only adverse effects found in clinical studies were mild gastrointestinal effects at the same level as under placebo. The most common adverse reactions (≥ 3%) are: upper respiratory tract infection, bronchitis, cough, flatulence and increased bilirubin. Origin and chemistry
Crofelemer is an oligomeric proanthocyanidin mixture primarily composed of (+)–catechin, (–)–epicatechin, (+)–gallocatechin, and (–)–epigallocatechin monomer units linked in random sequence, as represented below. The average degree of polymerization for the oligomers ranges between 5 and 7.5, as determined by phloroglucinol degradation. The substance is a purified oligomeric proanthocyanidin from the sap, or more correctly the latex, of the South American tree Croton lechleri (locally called Sangre de Grado or Sangre de Drago). This is one of several plants producing bright red latex or resin called "dragons blood". Crofelemer is a complex mixture of procyanidins and prodelphinidins with up to 30 (epi)catechin or (epi)gallocatechin units per molecule, resulting in a molecular mass of up to 9 kDa. History of Crude Plant Latex (Dragons Blood) and Crofelemer
The crude plant latex of C. lechleri is traditionally used in South American medicine for the treatment of diarrhea, wounds, inflammations, tumors, insect bites, and other conditions.
In 2012, crofelemer completed a Phase III trial, and it was approved in December 2012 by the FDA for the indication "symptomatic relief of non-infectious diarrhea in patients with HIV/AIDS on anti-retroviral therapy".The drug substance is manufactured by Glenmark Pharmaceuticals, and is manufactured as 125 mg delayed-release tablets by Patheon Pharmaceuticals Inc. for Napo Pharmaceuticals. References
External links
"Crofelemer". Drug Information Portal. U.S. National Library of Medicine.