BNF Categorisation and Structure

• The data aligns with the latest BNF categorisation held on NHSBSA drug databases. The British National Formulary (BNF) structure changed with BNF 70 (September 2015), but NHSBSA data continues to follow the BNF 68 structure.
• Chapter 19 is a general category for products that do not fit into standard BNF chapters. Some headings in this chapter may not clearly reflect the products within.
• To be able to classify items not covered within standard BNF chapters (1–15), the NHSBSA has created pseudo BNF chapters (20–23). These chapters primarily cover dressings and appliances, ensuring they can be classified and reported effectively within the NHSBSA's coding system.
• The BNF code does not include pack size details or further specificity beyond its defined structure.
• Drugs and chemical substances can appear in multiple BNF chapters or sections, such as Methadone.
• New BNF codes are created as needed, but changes to existing BNF codes occur once a year. For example, if a product moves from Chapter 03 to Chapter 04, this change takes effect in January.

Therapeutic Classification Limitations

Medicines are classified based on their primary therapeutic indication, but they may also be prescribed for other reasons that are not captured by NHSBSA during processing. The clinical indication of a prescription is not recorded, so it is not possible to determine the reason for prescribing.

Appliance BNF Coding Descriptions

Appliance BNF coding for BNF Paragraph, Subparagraph, and Chemical Substance fields is a representation of other fields to provide a more meaningful description. The BNF Presentation/Product field provides the actual appliance description.

Compatibility and Matching Considerationss

• Care should be taken when attempting to match BNF coding information from this dataset to other NHSBSA datasets, as other datasets may provide snapshots of data specific to individual prescription months, rather than dynamically updated versions.
• Previous historic versions transferred from the NHSBSA Information Service Portal have retained their original format and will not be updated to align with the current view.

Data Accuracy and Source Limitations

The accuracy of this dataset is dependent on the source CDR drug database, where the raw data is stored.

Removal of Invalid Products from BNF Structural Hierarchy

From version 88 onwards, all BNF datasets – including the year-end historic dataset – will exclude invalid products. To support transparency, any additions, removals, or amendments are recorded in the monthly changes dataset, which users can reference to track changes across the year.

Please note: Older versions (up to and including version 86) contained all products, including those that had become invalid. As a result, comparing historic versions with newer files may be challenging due to the inclusion of invalid products in earlier datasets.