FAQ: MDS – expiry date

I have items dispensed in MDS trays which have not been collected/delivered; is there an expiry date in terms of stability?

A monitored dosage system’s (MDS) expiry will be dependent on the dispensed items within it, as each item will have its own stability. Manufacturer’s advice should be referred to for relevant stability information; the Summary of Product Characteristics (SPC) for licensed medicines may also include useful information.

When items are placed in an MDS, they may be being stored outside of their product license/manufacturer’s recommendations. Therefore, it will be the clinical decision of the prescriber and the professional judgement of the Responsible Pharmacist whether it is appropriate to supply an MDS after a significant amount of time has passed after preparation. Additionally, the following need to be taken into consideration:

• Any changes to the dose/strength/formulation of the item
• Adherence issues which may account for uncollected/undelivered MDS
• Complexity of the dose regime, for example, irregular dosing or dose titrations
• Measures to mitigate against factors that may affect stability, for example heat and light
• Relevant pharmacy policies and procedures
• Storage and transport of the MDS

It is imperative to ensure that the MDS is collected by/delivered to the patient within the legal validity of the prescription used in its dispensing; prescriptions for Schedule 2, 3 and 4 Controlled Drugs are valid for 28 days from the appropriate date, and prescriptions for all other prescription-only medicines are valid for six months from the appropriate date.

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This FAQ is correct at the time of publishing.