TUESDAY, Sept. 14, 2004 (HealthDayNews) -- Lowering cholesterol with statins has been shown to prevent second heart attacks, but a new study finds that higher doses of one statin aren't much better than lower doses at preventing recurrent heart problems.
Moreover, high doses of the popular statin, Merck & Co.'s Zocor, increase the risk of developing myopathy, which is muscle weakness.
However, researchers claim that over the long term, patients taking high doses of Zocor have fewer cardiovascular events or deaths compared to those taking lower doses.
"This study supports the 'lower-cholesterol-is-better' concept for patients after acute coronary syndromes," said lead researcher Dr. James A. de Lemos, an associate professor of cardiology at the University of Texas Southwestern Medical Center. "There is greater benefit in terms of fewer complications after a heart attack."
In this study, called the A to Z trial, 2,265 patients suffering from acute heart problems were given 40 milligrams of Zocor daily for one month. After that, their dose of Zocor was increased to 80 milligrams per day.
The researchers compared these patients with 2,232 similar patients who were given a dummy drug for four months, followed by daily doses of 20 milligrams of Zocor, according to the report in the Sept. 15 issue of the Journal of the American Medical Association.
After eight months, cholesterol among patients taking 20 milligrams of Zocor dropped to an average of 77 milligrams per deciliter (mg/dL), compared with 63 mg/dL among patients taking 80 milligrams of Zocor, the researchers report.
In addition, among patients receiving low doses of Zocor, 343 had a heart attack, died from another heart problem, or were hospitalized for a heart problem, compared with 309 of the patients on high doses of Zocor.
While there was no significant difference between the two groups during the first four months of the study, patients who took higher doses of Zocor fared better after that, the researchers noted.
However, nine patients taking 80 milligrams of Zocor developed myopathy, while none of the patients taking 20 milligrams did.
"We have to pay attention to a higher risk of myopathy with the highest doses we tested," de Lemos said. "People may need to be monitored more closely when they are treated with the highest dose of statins."
However, de Lemos believes high doses of statins are important in treating patients after a heart attack. "Overall, the risk-benefit ratio would favor a more aggressive approach than physicians are typically doing," he said.
De Lemos does not believe the risks of side effects when using statins are confined to Zocor. He added, though, that other drugs and drug combinations can lower cholesterol and may not have the same risk.
As yet there has not been a head-to-head test of the various statins to see which, if any, is safer, de Lemos said. "No matter which statin is used, in high doses the side effects are greater," he said.
"Even though there was a very large cholesterol difference between the high and low dose Zocor, there wasn't a really clear reduction in adverse events," said Dr. Steven E. Nissen, a cardiologist at the Cleveland Clinic Foundation.
Nissen pointed out that cholesterol is only one factor that affects the outcome of patients with heart problems. "You can't necessarily predict what's going to happen by knowing what the cholesterol levels are," he said. Other factors, such as the levels of C-reactive protein, are also important, Nissen added.
Nissen, who wrote an accompanying editorial, also said Zocor appeared to have a lower safety profile compared with other statins. "This study taught us some lessons that we really have to look at each of the drugs individually. We can't just look at them as a group," he said.
"The label for Zocor recommends a starting dose of 40 milligrams for high-risk patients, with 80 milligrams as an option," said Tony Plohoros, a spokesman for Merck. The results of this trial give the company "no reason to change these recommendations."
The muscle problems and toxicity were nowhere near as serious as those caused by Baycol, a statin that was pulled from the market because of the dangerous side effects, the editorial noted.
Based on these results, Nissen believes doctors will reassess the statins they prescribe.
Read more about cholesterol-lowering drugs from the American Heart Association.