My GP has told me to take 10mg of isosorbide mononitrate twice daily, but with no times. Looking at the Electronic Medicines Compendium, it says they should be taken to allow a nitrate-free interval (presumably overnight.) Does this mean they should be at about 7am and 5pm rather than more evenly-spaced? How do others handle it.

I have had a headache today - also more chest pain.