SAN FRANCISCO, March 9, 2013 /PRNewswire/ -- Adding extended-release (ER) niacin to statins does not reduce the chances of high risk patients having a heart attack or stroke, Oxford University scientists leading the HPS2-THRIVE study have revealed at the ACC conference in San Francisco today. In addition, the researchers report that the use of ER niacin causes a significant number of different types of serious side effect. Some of these side effects were already known to be caused by niacin, but some of them were unexpected. Niacin has been used for many years to modify cholesterol levels in people at high risk of heart attacks and strokes. It is particularly widely used in the United States, although there is limited evidence that it reduces the risk of cardiovascular outcomes (e.g. heart attacks and strokes), especially when added to current cholesterol-lowering therapy. Flushing is a common side effect that reduces compliance with niacin therapy. In HPS2-THRIVE, the ER niacin was combined with a new drug called laropiprant (which is a prostaglandin receptor blocker) in order to reduce problems due to flushing. Over 25,000 patients with pre-existing cardiovascular disease from the UK, Scandinavia and China were recruited into HPS2-THRIVE. They were all given simvastatin (plus, when required, another cholesterol-lowering drug called ezetimibe) as background treatment to reduce their initial cholesterol level. They were then assigned at random to receive either the ER niacin with laropiprant or a dummy (placebo) treatment for about 4 years. HPS2-THRIVE is, by far, the biggest study of niacin ever undertaken. The use of randomised treatment assignment, and the large size and long duration, make the findings very reliable. The primary aim of the HPS2-THRIVE trial was to find out whether adding niacin to currently standard treatments (including effective statin-based cholesterol-lowering therapy) would produce worthwhile reductions in the risks of heart attacks, strokes or other cardiovascular outcomes. Among those who took the ER niacin combination 13.2% suffered a heart attack, stroke or had an arterial procedure compared with 13.7% in those who took the dummy (placebo) tablets ̶ a small but not clearly significant difference.