Tirzepatide in the BNF: the official prescribing reference explained

Why the BNF entry for tirzepatide matters to patients

The BNF (maintained jointly by the RCPCH and the Royal Pharmaceutical Society and freely searchable at bnf.nice.org.uk) is the reference document UK prescribers and pharmacists consult when initiating, monitoring or adjusting treatment. Its entry for tirzepatide is not a consumer guide; it is a clinical reference covering licensed indications, cautions, contraindications, side effects and monitoring requirements. For patients, the practical value is this: you can open the BNF listing in under a minute and confirm that the medicine your prescriber is discussing matches the licensed UK product, right down to the strengths and the Black Triangle status, and our Mounjaro BNF guide walks through exactly what you will find there. That small check is worth doing.

The BNF entry sits within a wider clinical framework shaped by NICE TA1026, published in December 2024 and updated in September 2025. The two sources are complementary: the BNF records what is licensed and how it should be used; NICE TA1026 tells NHS commissioners and clinicians for whom it is recommended and under what conditions. Understanding the difference helps patients ask better questions of whoever is prescribing for them.

What the clinical evidence behind the BNF entry shows

The BNF's safety and efficacy information draws on the SURMOUNT clinical programme. SURMOUNT-1, published in the New England Journal of Medicine, randomised 2,539 adults with obesity across 72 weeks. At the 15 mg dose, average body-weight reduction was around 20 to 21 per cent; some analyses placed it slightly higher, and our tirzepatide 30-week overview looks at how results develop across the earlier stages of treatment. These are trial averages, not personal predictions, and results vary considerably between individuals.

Later, SURMOUNT-5 ran a head-to-head comparison against semaglutide 2.4 mg in 751 adults without diabetes over 72 weeks. Tirzepatide produced greater average weight reduction in that trial, a finding that NICE's committee noted when assessing TA1026. The BNF does not reproduce trial statistics directly; instead it references the SmPC, which in turn reflects the totality of that evidence. For a fuller picture of how the two medicines compare, our Mounjaro vs tirzepatide page sets out the key differences.

Eligibility, cautions and the Black Triangle

Per the licensed SmPC that informs the BNF, tirzepatide is indicated for adults with a BMI of 30 or above, or 27 or above where at least one weight-related condition is present, for example, high blood pressure, dyslipidaemia, type 2 diabetes or obstructive sleep apnoea, and our tirzepatide licence page explains how those indications translate into practice for UK patients. UK guidance reduces the BMI threshold by 2.5 kg/m² for South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds. Meeting the licence criteria does not automatically mean treatment is appropriate; the BNF lists a range of cautions and contraindications, including a personal or family history of medullary thyroid carcinoma, pancreatitis and certain gastrointestinal conditions, that a prescriber weighs individually.

The Black Triangle (▼) is not a warning that tirzepatide is unsafe; it is an instruction to healthcare professionals and patients to report any suspected side effects promptly via the Yellow Card scheme at yellowcard.mhra.gov.uk. The designation is applied to newer medicines where the MHRA considers ongoing surveillance especially valuable and is typically reviewed after five years. Prescribers working to BNF standards will explain this and should invite you to report anything unusual.

How private prescribing fits within the BNF framework

NHS access to tirzepatide is phased and tied to specific eligibility cohorts under NICE TA1026. Many people considering treatment do not yet qualify through the NHS or prefer not to wait. A regulated private pharmacy operates within the same prescribing standards the BNF sets out; the medicine, the licensed doses and the clinical obligations are identical. The difference is who funds the treatment and how quickly it can be accessed.

At nume, a GPhC-registered Independent Prescriber reviews every consultation, the same clinical reference documents, including the BNF and the relevant NICE guidance, inform those decisions. If you would like to understand whether you are likely to be eligible and what the process involves, our weight-loss treatment overview is a useful starting point, and details of how the consultation works are on the about us page. For a broader look at how tirzepatide is used in UK clinical practice, the Mounjaro information page covers the medicine in full. When you are ready, you can check your eligibility through a free consultation, reviewed the same day by a named prescriber.