Which of the following is the main effect of HMG-CoA reductase inhibitors?

Decreasing LDL

(C) is the correct answer here. The key word is main. As mentioned before, the liver will up-regulate LDL receptors to take up more LDL particles, which will thus decrease the levels in the bloodstream. The effect is quite nice (20-60%). (A) is false because you wouldnt want to decrease HDL. (B) is false because the HDL-raising effect is quite minimal. (D) is technically true but it is not the MAIN effect of these drugs. These drugs are primarily used to lower LDL levels, which, as we have seen so far, is highly important. Actually, these statins can be combined with other drugs from other classes to get a combined effect. For instance, Advicor, which is a combination product of lovastatin and niacin, exists. Lovastatin will help lower LDL. Recall that niacin helps raise HDL. The same is true for Simcor (simvastatin and niacin). Caduet is actually a combination of atorvastatin and amlodipine, which is a nice combination to treat both atherosclerosis and coronary artery disease (discussed later).