Ok...yes, there were NO prescription drugs listed as having been in Anna's bedroom.
The only room containing prescription drugs was the guest room; so either Anna got them herself (when she needed help to get to the bathroom right in her suite) or someone brought them from the guest room(two rooms away).
Also...on a side note, I'd like to think there were 3 beds in the guest room; one of them being for Howard. hehehe!
Sounds like maybe they were hiding the drugs from Anna....