COLESEVELAM HCL

12.1 Mechanism of Action Primary Hyperlipidemia : Colesevelam hydrochloride, the active pharmaceutical ingredient in colesevelam hydrochloride, is a non-absorbed, lipid-lowering polymer that binds bile acids in the intestine, impeding their reabsorption. As the bile acid pool becomes depleted, the hepatic enzyme, cholesterol 7-α-hydroxylase, is upregulated, which increases the conversion of cholesterol to bile acids. This causes an increased demand for cholesterol in the liver cells, resulting in the dual effect of increasing transcription and activity of the cholesterol biosynthetic enzyme, HMG-CoA reductase, and increasing the number of hepatic LDL receptors. These compensatory effects result in increased clearance of LDL-C from the blood, resulting in decreased serum LDL-C levels. Serum TG levels may increase or remain unchanged. Type 2 Diabetes Mellitus: The mechanism by which colesevelam hydrochloride improves glycemic control is unknown.