In Maryland, you must show an ID, can only buy 2 boxes in 30 days, and must sign a paper list. So, that's 2 boxes per each pharmacy - not chain, but each one - per 30 days, IFF the person at the counter goes through the 30 days of records.

In Virginia, you go to the pharmacy counter, and ask for what you want, they hand it to you, you pay, you go. It's stupid that it's different in every state. I haven't tried buying any in DC, so don't know what it's like there.