Drugs like Nexium, Prilosec and Prevacid are incriminated. However, H2 blockers – another type of antacid drug – showed no such association. This is green light for cimetidine and ranitidine (brand examples Zantac and Tagamet). The conclusion of the research is important because it showed a high risk up to 16 – 21 percent in heart attack increasing. The identified dangerous effect of some drugs is due to modification of the endothelium of the blood vessels. “Our report raises concerns that these drugs – which are available over the counter and are among the most commonly prescribed drugs in the world – may not be as safe as we previously assumed,” the authors said. According to the study, an estimated 113 million prescriptions for those drugs are issued around the world each year.