Nitrate tolerance - this can occur with all nitrates. In order to minimise this use a dosing regimen which includes an 8 hour nitrate-free interval corresponding to the least symptomatic part of the 24 hour period (usually at night). Isosorbide mononitrate modified-release tablets are formulated to give a nitrate-free period.
Isosorbide mononitrate standard-release tablets should be given twice daily 6-8 hours apart eg morning and early afternoon to avoid nitrate tolerance.
Guidance for switching between isosorbide preparations
CG126: Stable angina: management, July 2011 (updated August 2016)
