Sorry, no definitions found.
Sorry, no etymologies found.
But pharmakon, like altus, isn't really an auto-antonym; most remedies are poisons if given in the wrong fashion, and deep/high, as pf says, is just a matter of perspective.
I don't really think this fits into the auto-antonym category, since the only opposition between 'high' and 'deep' is the lexical one created by English vocabulary -- if you think about it, the real-world situation is the same.
This is an interesting choice because "special" is an auto-antonym that, like