The American Heart Association says high cholesterol affects more than 30 million Americans, and two of the most popular prescription drugs used widely to treat it are in question again.

Niaspan and Zetia were subject to a third test of their effectiveness for lowering LDL or bad cholesterol levels, and the results were not good.

Vytorin is another drug also in question, although it was not part of the study, it's a combination medication that includes Zetia. So if you're one of the many Americans relying on one of these drugs for your health, you might want to talk to your doctor.

According to Merck & Co., American doctors wrote more than 29 million prescriptions for two popular cholesterol drugs last year alone, and now, some cardiologists aren't sure the drugs are doing their job.

Cardiologist Ryan Whitney of Bryan LGH Medical Center estimates about 5 to 10 percent of Lincoln residents are using Niaspan, Zetia, or Vytorin.

"Zetia is primarily used to lower the LDL or bad cholesterol, Niaspan is been used more commonly to raise HDL or good cholesterol, but it also has the ability to lower bad cholesterol, and improve your triglycerides also.

Dr. Whitney says they're not dangerous, the latest of three studies does suggest the drugs are ineffective.

"All the studies done with Zetia so far have been with surrogate end points. In other words, we've looked at the thickness of the corroded arteries and chosen that to represent what might be going on in the arteries of the heart. There are some studies going on that are looking at what we call hard end points, stroke, heart attack, death, and those studies won't be out for another year or two. But those studies will tell us the final answer as to whether or not the medications really are doing what they tell us they're supposed to do," Dr. Whitney said.

In the mean time, he says there are some other treatment options.

"If patients are concerned, they should certainly contact their prescribing physician. Some patients may be willing to or interested in switching from one medication to another, keep in mind that each medication has its own set of side effects, and not everybody can tolerate every medication," he said.

Dr. Whitney says the vitamin niacin, and some plant-derived supplements available over the counter can also help, along with the classic, and often over-looked, diet and exercise.

There has also recently been some talk in the medical community about Niaspan, Zetia and Vytorin and a possible link to cancer, but Dr. Whitney says cardiologists and oncologists have looked into it, and the overwhelming scientific opinion is that they provide no risk for cancer.

For more information on the cholesterol drugs, just click on the links below. To hear more from Dr. Whitney, click on the video links above.