A study says one in five new drugs has serious side effects that show up after the medicine got federal approval. The researchers suggest doctors should prescribe older drugs when possible, unless the new one is truly superior. Doctor Sidney Wolfe of Public Citizen Health Research Group says that do to otherwise is "like playing Russian roulette". Food and Drug Administration officials counter that the analysis overstates the problem. One says a drug can cause side effects in some patients but not others. The report and the FDA response are in the Journal of the American Medical Association.