Prescribers may consider switching patients to a modified-release preparation as an alternative.
Data on the dose equivalence of isosorbide mononitrate standard-release tablets and modified-release tablets is currently limited. Where available formulations allow, an initial mg per mg substitution (using the same overall daily dose) is advised. Further dose adjustment can be considered on an individual patient basis.
If necessary, an unlicensed product can be supplied, although the prescriber must ensure that the prescription clearly shows this intention.
You can find details of alternative formulations of isosorbide mononitrate licensed for the treatment of angina in an easy-to-use MIMS table.