Why would walgreen's claim nitroglycerin is a controlled substance and refuse a refill?

Not a c.s.: Controlled substance is an official dea classification. I do not see Nitroglycerin on that list. It does require a doctor's prescription. Unless nitro's dea classification has changed, walgreen would be in error to claim this. Here is a link directly to the dea with definitions and list of medications for firsthand information: http://www.Deadiversion.Usdoj.Gov/schedules/#define.