Vancouver
This is the Vancouver style for referencing, used at the Univerity of Portsmouth within the School of Pharmacy and Biomedical Sciences and the Radiography departments.
This guide is modelled on Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers (2nd edition). You may wish to consult this source directly for additional information or examples.
The key thing to remember here is that the British National Formulary is not the author! The author for the British National Formulary is the Joint Formulary Committee.
Standard Format
Author AA/Organisation. Title of book. Edition. Place of publication: Publisher; Year of publication. Title of part; Location of part.
Example
Joint Formulary Committee. British National Formulary [Internet]. London: British Medical Association and Royal Pharmaceutical Society of Great Britain; [updated 2021 Apr 29; cited 2021 May 19]. Paracetamol; Available from: https://bnf.nice.org.uk/drug/paracetamol.html