Some cholesterol controlling drugs known as statins may negatively impact the memory, according to a new study from researchers at the UK's University of Bristol. Researchers administered two different leading statin drugs to a group of rats. The two drugs tested were pravastatin (Pravachol) and atorvostatin (Lipitor).Over the course of 18 days the rats were given a scaled dose of either drug. Though their side effects were the same otherwise, they found that the atorvastatin caused slight memory impairment in the rats."This finding is novel and likely reflects both the anecdotal reports and FDA advice. What is most interesting is that it is not a feature of all statins," the researchers said. "However, in order to better understand the relationship between statin treatment and cognitive function, further studies are needed."