Plavix, manufactured by Bristol-Meyers Squibb and Sanofi Aventis, is a blood thinner that was marketed as being superior to aspirin in preventing heart attacks and strokes. The drug caused serious adverse side effects in patients with peptic ulcer disorder (PUD), however, because Plavix can increase the risk of gastrointestinal bleeding when taken with some common heartburn medications. A recent study published in the New England Journal of Medicine found that people who took Plavix developed 12 times as many ulcers as people who took aspirin in combination with a heartburn pill. In addition, people with high cholesterol or high blood pressure who take Plavix have double the risk of suffering a heart attack, stroke, or internal bleeding.