Name: Cholestyramine (Cholybar)
Class: Blood Lipid-Lowering Agent (Resin)
Mechanism: Binds bile acids in intestine ® defecation of bile acids, conversion of cholesterol to bile acids, ¯ pool of hepatic cholesterol, activity of apoB/E receptor, LDL clearance, ¯ plasma cholesterol. Moderate ¯ in cholesterol & LDL. Mild in HDL. Zero-moderate in TG & VLDL.
Absorption: Oral. No absorption.
Dist.: Metabolism.: Excretion, t½:
Toxicity/S.E.s: Up to 50% refuse to continue Rx. Flatulence, constipation, gas, n/v, steatorrhea. Supersaturation of cholesterol in bile ® gallstones, need for cholecystectomy. ¯ bile ® ¯ absorption of lipid-soluble drugs/vitamins. Binds acidic drugs. Weak stim. of VLDL synth. Do not use in pts. w/hyperTG w/o concurrent TG-lowering agent.
Utility: Treat hyperlipidemia IIA/IIB. Use alone or w/niacin, probucol, or HMG CoA reductase inhib.
Special Features: GI S.E.s reduced if taken immediately prior to meals. ½ dose + Metamucil™ ® ¯ constipation & bloating, but sim. efficacy.