If a statin alone does not lower LDL levels, which medication is likely to be added?

Cholestyramine is classified as a bile acid sequestrant and is often employed as an adjunct therapy when statins alone do not sufficiently lower LDL cholesterol levels. The mechanism of action of cholestyramine involves binding bile acids in the intestine, which then prevents their reabsorption. This process forces the liver to utilize more cholesterol to produce new bile acids, thereby resulting in a reduction of circulating LDL cholesterol levels.

Adding cholestyramine can be particularly beneficial for patients who either do not achieve adequate LDL lowering with statins or who may have side effects from higher doses of statins. Combining therapies can enhance lipid-lowering effects and provide better management of cholesterol levels.

In contrast, the other options do not have a primary role in lowering LDL cholesterol. Calcium carbonate is mainly used as a dietary supplement or antacid, digoxin is a cardiac glycoside used primarily to treat heart failure and arrhythmias, and vitamin D is involved in calcium metabolism but does not impact lipid levels significantly. Thus, cholestyramine stands out as the appropriate choice when statin therapy alone is insufficient.