Cholesterol-lowering medicines known as statins lower the chances of a heart attack and death in people who have an elevated risk of developing heart disease or who already have heart disease. Nearly 22 percent of adults 45 or older take a statin drug, making this the most commonly prescribed class of medications in the U.S. But figuring out which one is right for your situation or if you need to take one at all can be a complex decision.

There are seven statins, but they're not all the same. Some deliver a greater reduction in cholesterol than others. In addition, some statins are backed by stronger evidence that they reduce the risk of a heart attack, death from heart disease, or stroke.

Statins can vary widely in cost as well—from as little as $11 per month to more than $200. Most people who take them must continue to do so for years—perhaps for the rest of their life—so the cost can be an important factor to consider.

Your individual circumstances, such as how much you need to lower your cholesterol and whether you have heart disease or have had a heart attack, should also be considered when looking at your options. Certain statins are better depending on your health status.

  Taking the evidence for effectiveness, safety, and cost into account, we have chosen four statins as Consumer Reports Health Best Buy Drugs:

• Generic lovastatin or pravastatin—if you need to lower "bad" (LDL) cholesterol by less than 30 percent.
• Generic simvastatin (20 mg or 40 mg)—if you need an LDL reduction of 30 percent or more and/or have heart disease or diabetes, or if you've had a heart attack or have acute coronary syndrome and your LDL level is not highly elevated.
• Atorvastatin (Lipitor) (40 mg or 80 mg)—if you have had a heart attack or have acute coronary syndrome and your LDL is highly elevated.

Most people who need a statin should take the lowest dose that reduces their LDL cholesterol to an acceptable "target" level, because higher doses pose a greater risk of serious side effects, such as muscle, kidney, and liver problems. But some people—such as those who have had a heart attack—might need a higher dose.

No matter what dose you take, if you experience muscle aches and pains when taking a statin, contact your doctor immediately. Also, ask your doctor about splitting your statin pills. This can save you money and is a widely accepted practice.