Doctors are trying to calm patients’ concerns after a study released in January found that the drug Vytorin failed to slow clogging in the arteries and could even increase the risk for heart disease.

The two-year study with 720 patients suggested that Vytorin was no more effective than an older drug, the statin Zocor, in curbing the buildup of arterial plaque. In fact, plaque increased slightly with Vytorin, which is a combination of Zocor and Zetia, a nonstatin.

Vytorin manufacturer Merck/Schering-Plough Pharmaceuticals maintains that the drug helps lower cholesterol levels.

Steven Nissen, M.D., of the Cleveland Clinic urges patients to talk to their doctors before deciding whether to continue with Vytorin. “Ask if you would do as well on a generic statin alone,” he says. “Until there’s better evidence, physicians should only prescribe these [nonstatin] drugs for patients who can’t tolerate statins or don’t get to their ideal [cholesterol levels] using statins alone.”