NHS Greater Glasgow & Clyde Area Drug and Therapeutics Committee
Greater Glasgow and Clyde Medicines
Medicines Update

Prescribing Medicines by Brand

Key Messages

  • Generic prescribing is usually recommended due to cost-effectiveness, however in certain circumstances it is important to prescribe medication by brand name
  • Examples of medication to be prescribed by brand include immunosuppressants, some antiepileptics, biosimilar products, insulin and medication in devices (e.g. pens, inhalers)
  • Reasons for brand prescribing include differences in bioavailability, differences in devices, cost, and to ensure any adverse events are reported for a specific brand (e.g. biosimilars)
  • If there is a supply problem with a specific brand, refer to the supply problem page on StaffNet or seek advice (to reduce risk of missed doses)

Examples of brand prescribing

Immunosuppressants such as tacrolimus, mycophenolate and ciclosporin all have narrow therapeutic indexes and inadvertent switching between brands may lead to toxicity or graft rejection. The MHRA advice on tacrolimus notes that even minor differences in blood levels have the potential to cause graft rejection or toxicity.


Antiepileptics are divided into 3 categories, based on their therapeutic index, solubility and absorption. These categories indicate the importance of maintaining patients on the same manufacturer’s product for certain medications.  


A biosimilar product is defined as a ‘new biological product that has been developed to be similar to an existing biological product, or ‘reference’ product.’ The structures of biosimilars are different to those of the reference product in terms of complexity. Biosimilars are subject to black triangle status (▼) at the time of initial authorisation and therefore it is important to prescribe by brand name to ensure any adverse drug reactions can be assigned to the correct product. Please report suspected adverse reactions using the Yellow Card Scheme. Examples of biological products where biosimilars are available include enoxaparin, epoetin alpha, and some insulin preparations (e.g. glargine and lispro).

Other examples of medicines where brand prescribing is recommended

(If viewing table on a mobile device switch to landscape)


Reason for Brand Prescribing


Various reasons including safety, patient familiarity, differences in devices, biosimilars, and high strength preparations.

Lithium preparations 

Preparations vary widely in bioavailability, narrow therapeutic index (changing preparation requires the same precautions as initiation)


Dry powder inhalers

Beclometasone CFC-free pMDIs




Differences in devices

Not interchangeable e.g. Qvar® approximately twice as potent as Clenil®

NB. In GGC, all inhalers should be prescribed by

brand (with the exception of salbutamol pMDI)

Oral MR opioid preparations:

Morphine MR/ Oxycodone MR/ Tramadol MR



Available as 12 hourly or 24 hourly; reduce the risk of confusion and error in dispensing and administration

Opioid patches:

Buprenorphine patches


Fentanyl patches


Available as 72 hourly, 96 hourly or 7-day preparations; reduce the risk of confusion and error in dispensing and administration

Available as matrix or reservoir – reservoir patches cannot be cut as this can lead to rapid release and overdose. Reduce the risk of confusion and error in dispensing and administration

Calcium channel blockers:

Diltiazem MR preparations > 60mg/ Nifedipine MR  


Different brands may not have the same clinical effect

Theophylline MR/Aminophylline MR

Bioavailability differs between brands, narrow therapeutic index

Mesalazine oral preparations

Delivery characteristics may vary

Methylphenidate MR

MR preparations contain both immediate-release (IR) and MR; the proportion of each varies between brands

*MR = modified release

Please note, the above list is not exhaustive. Refer to the UK Medicines Information Q&A for further information. Also refer to the Formulary here for local advice on preferred brands in GGC.


Published 11/09/19. Medicines Update blogs are correct at the time of publication.