The combination of simvastatin and niacin can reduce the risk factors associated with myocardial infarction by 60-90% in patients at high risk of a major cardiac event, researchers at the University of Washington in Seattle have found.
Furthermore, this same patient population should be advised to stop taking antioxidant vitamins. "Physicians should question their patients and have them stop using antioxidant vitamins. It is the opposite of what I used to say," the study's lead author, Dr B Greg Brown of the University of Washington commented.
The recommendations emanate from new research, which found that a combination of antioxidant vitamins such as vitamin E, vitamin C, and b carotene, blunt the rise in high density lipoprotein (HDL) cholesterol levels seen with the simvastatin and niacin combination. The study's authors said, however, that they were not sure why the antioxidant vitamins had this effect (New England Journal of Medicine 2001;345:1583-92).
The three year, double blind trial included 160 patients with low HDL cholesterol levels ( £ 35 mg/dl ( £ 0.9 mmol/l)), normal low density lipoprotein (LDL) cholesterol levels, and clinical coronary artery disease. Patients were randomised to receive simvastatin plus niacin; antioxidants; simvastatin, niacin, and antioxidants; or placebo. All patients received exercise training, as well as counselling on smoking and diet.
In total, researchers found that in the patients receiving the statin plus niacin the mean HDL cholesterol level increased by 26%, from 31 mg/dl to 39 mg/dl and the mean LDL cholesterol level dropped by about 40%, from 125 mg/dl to 76 mg/dl.
At the start of the study and again after three years of treatment, angiography was performed to assess build up of plaque. At the end of three years the coronary arteries of the people receiving the statin plus niacin were less blocked than those of the people in the other groups. "When niacin is combined with a statin, the artery blockage actually improves a bit, on average," Dr Brown said. "I think we will see more use of niacin," Dr. Brown added. "It has been underused as a pharmaceutical."
Niacin is not as easily tolerated as statins, sometimes causing flushing as well as adverse effects on blood sugar and uric acid levels.
As for antioxidants, Dr Brown said that statin users who "really want to raise HDL . . . probably should not be using antioxidant vitamins." Unless more compelling evidence appears, he said, "We see little justification for the use of antioxidant vitamins for the prevention of cardiovascular events."
Only one other study has found a benefit from antioxidants, whereas several—including an earlier version of this same study—have suggested that there was no effect or a negative effect (Arteriosclerosis, Thrombosis, and Vascular Biology 2001;21:1320).
Dr Norman Krinsky of Tufts University in Massachusetts, who headed an Institute of Medicine panel on antioxidants, said that the study "raises a real question" about the possible interference of the nutrients with cholesterol drugs. But Dr Krinsky said, "A blanket condemnation of antioxidants for prevention may be premature."
