A few years ago I helped a friend track these down. Paddock Labs is the only company that makes them (Belladona and Opium) and they periodically suspend production. (I was told because they can't always get the raw materials..i.e. opium).
You might try one of the large national pharmacy chains(Walgreens, CVS) and ask if they can track it down for you. If the local pharmacist isn't being all that helpful, ask for the name of the regional pharmacy manager.