Cholestyramine

Colestyramine (INN) or cholestyramine (USAN) (trade names Questran, Questran Light, Cholybar, Olestyr) is a bile acid sequestrant, which binds bile in the gastrointestinal tract to prevent its reabsorption. It is a strong ion exchange resin, which means it can exchange its chloride anions with anionic bile acids in the gastrointestinal tract and bind them strongly in the resin matrix. The functional group of the anion exchange resin is a quaternary ammonium group attached to an inert styrene-divinylbenzene copolymer.