I suppose the data is only as good as the person entering it...
And the computers should flash up some sort of warning that, 'If patient is on X, for God's sake don't give them Y'.
Now I'd happily see the man dead, but every so often my dad goes to the doctor's with a printed list of the tablets he's taking so as to keep
their records updated
He actually bought one of those 'medication dictionaries' you see in book shops and doesn't take a prescription until he's checked it in that or Googled it...