Back in the day we just used hospital DEA but nowadays I'm pretty sure that every intern (especially if they're writing rx) should have an NPI. It's like the first thing they do at hospital orientation. And it's not that hard to do an NPI search, even on google.
This never worked for me for discharge pt's (compared to clinic) , since interns/residents are all over the place and the phone number was usually the hospital switchboard. And of course the resident name is illegible without even a pager number...