Start an entirely new Game slot on Normal difficulty and exit to menu after gaining control of Artyom (first autosave) in Moscow. Then start a Normal difficulty playthrough from Chapter select.
This will ensure that you do not have to rerun the chapter again like I did. (I started from a Reader difficulty save slot) :)
I hope that helps someone.
From there, save often and reload if you take a bunch of damage in a fight. Disassemble your medkits at workbenches where possible to remove the temptation or limit the possibility of accidental usage. I found only the first and last part of the Chapter I had to be careful in.