The Department of Health has written to colleagues advising that there are supply issues with all normal release isosorbide mononitrate due to a problem with the availability of raw materials.
This issue is affecting normal release 10mg, 20mg and 40mg tablets and may continue for several months but modified release products are unaffected. Limited stock is entering the supply chain and some companies are obtaining unlicensed product from abroad on an individual patient basis.
Clinicians are being advised to consider changing patients affected by this shortage to an equivalent dose of a modified release product. Data regarding switching is limited but a mg for mg switch is suggested thus maintaining the same total daily dose initially. Further dose adjustments may be necessary based on clinical response.
Pharmacists who are presented with a prescription for which they are unable to obtain stock should contact, or refer the patient back to, the prescriber to discuss alternative solutions.
Action: Clinicians and Pharmacists should be aware of this shortage and work together to ensure continuity of an appropriate treatment.