BRUSSELS At a drug wholesaler warehouse in Belgium , shelves are emptier than they used to be. Like other EU nations, Belgium has increasingly experienced medicine shortages that vex pharmacists, exasperate patients and risk overloading public health services. "There are often several dozen medications that are in short supply simultaneously, which makes our lives very difficult," said Didier Ronsyn, a Brussels pharmacist. An EU audit last month found shortages were a "chronic headache" across