BNF for dummies

The British National Formulary is a collection of drugs that may be prescribed, with hierarchical identifiers. There is apparently a new hierarchy, but we plan to continue using the older codes.

We've got a blog post covering much of this.

The hierarchy is as follows:

• Chapters, eg 06: Endocrine System
• Sections, eg 0601: Drugs Used In Diabetes
• Paragraphs/subsections, eg 060101: Insulin
• Subparagraphs, eg 0601012
• Chemicals, eg 0601012W0: Biphasic Insulin Aspart
• Products, eg 0601012W0AA: Ins Biphasic Aspart or 0601012W0BB: Ins Biphasic Aspart (Novo-Nordisk) -- if the last two characters of the code are "AA", the product is generic, otherwise it's branded
• Presentations/product formats, eg 0601012W0AAABAB: Ins Biphasic Aspart_Inj 100u/ml 3mlPfPen

We have pages showing the trends for all levels of the hierarchy from chapter to chemical, linked to above.

The analyse page can provide breakdowns of prescribing at all levels of the BNF hierarchy apart from subparagraph. (There is an issue about this.)

The monthly prescribing data that we import has one row per presentation per practice, with quantity and number of items prescribed (these are different), and cost. This data is then transformed (via BigQuery) and loaded into the frontend_prescription_YYYYMM table, and aggregated into the vw__ tables and measure tables.