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Update on the substitution of medicines in the event of shortages

Following the governments January publication of a policy paper on obtaining medications in the event of no deal Brexit, we would like to alert Keep Me Informed users to the conditions and medicines where substitution of medicines should be approached with caution.

The government stated that around three-quarters of the medicines and over half the devices and one-use medical products (such as syringes) that the NHS uses, come into the UK via the EU.

'The government has analysed the supply chain, made plans to reduce the risk of disruption, and given instructions to pharmaceutical companies to ensure that they have adequate stocks to cope with any potential delays at the border.'

Anti epileptic treatments are one group where consistent use of the same prescribed medicine is required.

Other considerations are where medicines should be prescribed by brand name. For example, all biologicals should be prescribed by brand name.

This is due to a variety of factors such as:
  • bioavailability differences
  • modified-release characteristics
  • formulation difference of effect
  • patient familiarity
  • different licensed indications
The UK Medicines Information group published guidance in 2017. A link to this document is available in the main article (click on this headline to access).


Consistency of medicine supply.

Epilepsy medicines
provide information on medication consistency.

Brand name consistency
  • Medicines should be prescribed by brand name in the following situations:
  • Where there is a difference in bioavailability between brands of the same medicine
  • Where modified-release (MR) preparations are not interchangeable
  • Where there are important differences in formulation between brands of the same medicine
  • Where administration devices have different instructions for use and patient familiarity with one product is important
  • Where the product is a biological rather than chemical entity
Brand-name prescribing may also be preferred:
  • Where products contain more than one ingredient and brand-name prescribing aids identification
  • Where branded and generic preparations have different licensed indications
  • For some patients, where differences in product name, presentation, appearance or taste may lead to anxiety, confusion, dosing errors and reduced adherence
For further information please use link below to download full document

Link to SPS/UKMI/NHS information on brand name prescribing

Reporting of suspected adverse reactions

Reporting suspected adverse reactions (side effects) after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals or patients are asked to report any suspected adverse reactions via the Yellow Card Scheme at or search for MHRA Yellow Card in the Google Play or Apple App Store.

Disclaimer: This site is designed to offer information for general educational purposes only. The health information furnished on this site and the interactive responses are not intended to be professional advice and are not intended to replace personal consultation with a qualified physician, pharmacist, or other healthcare professional. We cannot provide individual medical advice. You must always seek the advice of a professional for questions related to a disease, disease symptoms, and appropriate therapeutic treatments.