A medicine can be licensed in the UK and still not be the option supported by a local NHS system. The local formulary records preferred choices, restrictions and governance across an ICB, health board, Trust or integrated system. This guide explains how to find it, read its status labels and place it alongside product information and clinical guidance.
What a local formulary is, and is not
A local formulary is an agreed list of preferred and supported medicines designed to promote safe, effective and economical prescribing and continuity across care settings. It answers what the local system has selected and under what governance. The relevant SmPC on eMC answers the licensed product question; NICE, SPS and specialist guidance support recommendations; the formulary governs local implementation. None replaces patient-specific clinical judgement.
Finding the correct formulary
The reliable method: search the patient's ICB, health board or trust name plus "formulary", because the formulary follows the patient's system, which is not always yours. Then three checks before trusting it: whether the site covers primary care, secondary care or both, since some systems split them; the last-updated date, because stale formularies mislead confidently; and whether a more specific companion exists, an antimicrobial formulary, a paediatric formulary, mental health or shared-care documents, since the general formulary often defers to them. Bookmark the result per patch you work in; locums and portfolio GPs should treat a one-page formulary crib per site as standard kit.
Reading an entry
Formulary entries carry more information than the drug name. Preferred or first-choice status tells you the system's default; alternative or second-line status tells you what needs a reason. Specialist-initiation flags mean the first prescription belongs elsewhere; shared-care requirements mean ongoing prescribing transfers only with a documented agreement covering monitoring and responsibility; non-formulary or exceptional-use status means an application process exists and pharmacy can tell you where it lives. And the linked local guideline, often one click away, is frequently the actual answer to the clinical question that sent you there.
Red, amber, green, read locally
Most systems run a RAG classification, and the universal core is that colours allocate prescribing and monitoring responsibility: green broadly prescribable in primary care, red retained by specialists, amber somewhere between, typically with shared-care or initiation conditions. The essential caveat: exact definitions vary between systems, ambers especially, some distinguish amber-with-shared-care from amber-initiation, some add sub-colours, and assuming your last ICB's key applies to this one is a genuine error mode. Every formulary publishes its own key; read it once per system and the colours become reliable.
The stack in action
For nitrofurantoin, use local UTI guidance to establish whether it is preferred for the presentation, then check the exact SmPC for product-specific dosing, contraindications and warnings and add applicable safety guidance. For paediatric amoxicillin, local antimicrobial and paediatric guidance determine indication and regimen, while the exact liquid’s SmPC confirms concentration, reconstitution, storage and excipients. The formulary answers the local-selection question and hands the rest to the source designed for it.
Frequently asked questions
What If the Formulary and Another Source Appear to Disagree?
First identify whether the difference concerns licensing, a national clinical recommendation or local implementation. Check the relevant SmPC and applicable NICE, SPS or specialist guidance. Escalate a genuine conflict to pharmacy or the medicines-management team rather than choosing a source by habit.
Do formularies apply to private prescribing?
Their governance applies to NHS prescribing; their clinical logic often remains informative anywhere. Cost-driven choices, though, are explicitly NHS-system decisions.
How current are formulary websites, honestly?
Variable, which is why the last-updated date check is step one; most large systems now maintain them actively. When a page looks stale, the antimicrobial and shared-care documents are usually the best-maintained corners to trust first.
I work across several systems as a locum; any shortcut?
A one-page crib per site, built on day one: formulary URL, the RAG key's local quirks, the antimicrobial guide, and the shared-care list for the drugs you actually see. Ten minutes per system, and the commonest locum prescribing frictions disappear.
Orient on the medicine before you check the local position →