I have this same problem, and it makes me so mad! I've always had sinus problems - bad enough that they'd make me sick to my stomach and dizzy - and for years I've taken the Tylenol Sinus capsules, which were the only ones that really worked. Instead of just drying you up, these actually opened your sinuses up and let them drain (yuk!), taking the pressure off and getting rid of the pain. NOW, because of all the goofy meth manufacturers, this stuff is "behind the counter" and you have to sign for it. No more comparison shopping or checking out the labels to see which ones you want, but this was fine with me. And the brands still on the shelves didn't have the ingredient in them that made them work well. But what happened, at least here, is that they stopped carrying a lot of the popular brands and you never know what they'll have. At our local drug store, they literally have a laundry basket behind the counter, full of different cold and sinus remedies, and they dig through it to see what they've got, and they very seldom have the Tylenol Sinus capsules! I usually end up with some store brand that isn't the same and doesn't work as well.
But it's this way everywhere! When my son worked in an auto parts store, they'd get periodic visits from the Drug Task Force folks. They wanted them to try to get the names and license plate numbers of anyone buying large quantities of certain products that can be used to make meth!