Mechanism of Action

Mytesi® (crofelemer 125 mg delayed-release tablets) is an inhibitor of both the cyclic adenosine monophosphate (cAMP)-stimulated cystic fibrosis transmembrane conductance regulator (CFTR) chloride ion (Cl¯) channel, and the calcium-activated Cl¯ channels (CaCC) at the luminal membrane of enterocytes. The CFTR Cl¯ channel and CaCC regulate Cl¯ and fluid secretion by intestinal epithelial cells. Crofelemer acts by blocking Cl¯ secretion and accompanying high volume water loss in diarrhea, normalizing the flow of Cl¯ and water in the GI tract. Mytesi® is a non-opiate and non-antibiotic anti-secretory agent that has minimal oral absorption.


Important Safety Information

Mytesi® (crofelemer 125 mg delayed-release tablets) is approved for the symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS on antiretroviral therapy. Rule out infectious etiologies of diarrhea before starting Mytesi® in order to avoid the risk of potential worsening of disease due to delay of appropriate therapy. The most common adverse events (incidence ≥ 3%) reported in Mytesi® clinical trials were upper respiratory tract infection, bronchitis, cough, flatulence, and increased billirubin.

Please see further details and complete Prescribing Information available at


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