Tegaserod- 13 C,d 3 (maleate) is the 13 C- and deuterium labeled Tegaserod (maleate). Tegaserod maleate is a selective 5-HT4 receptor partial agonist and a 5-HT2B receptor antagonist. Tegaserod maleate exhibits a promotile effect throughout the gastrointestinal (GI) tract.