Q. I'm 71 and have taken 20 milligrams (mg) of atorva­statin (Lipitor) since 2010, after an angiogram showed a 90% blockage of a small coronary artery. But I've never had angina or a heart attack. My LDL is 70 mg/dL. Should I switch to 20 mg of rosuvastatin (Crestor), which I understand is a higher-intensity statin?

A. You're correct — a 20-mg dose of rosuvastatin is considered high-intensity statin therapy. Before getting into my advice, let me first explain what we mean by statin intensity.

Currently, there are eight different cholesterol-lowering statins on the market, each available in different dosages. In general, the higher the dosage, the more they lower your LDL cholesterol. However, some statins (especially rosuvastatin) lower LDL cholesterol better than others. So experts have classified statin therapy into three categories (low, moderate, or high intensity) based on how much they can lower LDL. As you can see by the table below, a statin can fall into more than one intensity category, depending on the dosage. For example, 10 or 20 mg of atorvastatin daily is considered moderate intensity, while 40 to 80 mg is high intensity.

The choice of a statin depends on a person's risk. For someone with high LDL but no other risk factors or evidence of coronary artery disease, moderate-intensity therapy makes sense. But for someone like you, with known coronary artery disease, the guidelines recommended high-intensity therapy, as several trials have documented a lower risk of heart attack and stroke for people on high-intensity therapy compared with moderate-intensity therapy.

The guidelines also recommended lowering LDL by 50% or aiming for an LDL of less than 70 mg/dl. Since you are close to that goal and have not had a heart attack, stroke, or other major cardiovascular problem, switching to rosuvastatin is not essential. However, all trials of cholesterol-lowering medications have found that lower is better for LDL. Because rosuvastatin is the most potent statin, switching could provide more protection for you.

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