British National Formulary : BNF 91, March – September 2026

Practical and evidence-based, BNF is an integral part of the UK’s healthcare infrastructure and relied on by health professionals who prescribe, dispense, and administer medicines globally. Containing guidance on best practice in prescribing, as well as legal and ethical considerations, BNF supports safe and effective decision-making at the point of care.

Extensive content updates in the BNF 91 edition include:

New monographs for:

Abrysvo® and Arexvy® [respiratory syncytial virus (RSV) vaccine] for immunisation against respiratory syncytial virus
Filspari® [sparsentan] for primary immunoglobulin A (IgA) nephropathy
IXCHIQ® [chikungunya vaccine (live)] for immunisation against chikungunya
Livdelzi® [seladelpar] for primary biliary cholangitis
Nemluvio® [nemolizumab] for moderate-to-severe atopic eczema and moderate-to-severe prurigo nodularis
Piperaquine phosphate with artenimol for treatment of falciparum malaria
Suvexx® [sumatriptan with naproxen] for treatment of acute migraine
Tzield® [teplizumab] for type 1 diabetes mellitus
Vimkunya® [chikungunya vaccine (inactivated)] for immunisation against chikungunya
MHRA advice on:

Isotretinoin: updates to prescribing guidance and survey of services
Ivacaftor with tezacaftor and elexacaftor (Kaftrio®): risk of psychological side effects
Paracetamol: reminder that taking paracetamol during pregnancy remains safe
Respiratory syncytial virus (RSV) vaccine (Abrysvo® and Arexvy®): be alert to a small risk of Guillain-Barré syndrome following vaccination in older adults
Short-acting beta2-agonists (SABA) (salbutamol and terbutaline sulfate): reminder of the risks from overuse in asthma and to be aware of changes in the SABA prescribing guidelines
Thiopurines: risk of intrahepatic cholestasis of pregnancy
Valproate: updated safety and educational materials to support patient discussion on reproductive risks
Other significant changes include updated guidance on:

Amoxicillin: updated indications and dose for prophylaxis of recurrent urinary-tract infection
Antibacterials, principles of therapy: updated guidance on notifiable diseases
Antibacterials, use for prophylaxis: updated guidance for Haemophilus influenzae type b infection
Asthma, acute: update to criteria for severity of acute asthma attacks
Benralizumab: new indication and dose for eosinophilic granulomatosis with polyangiitis
Cefalexin: updated indications and dose for prophylaxis of recurrent urinary-tract infection
Citalopram: new indications and dosing for known CYP2C19 poor metabolisers
COVID-19: updated vaccine monograph and guidance on management of COVID-19
Escitalopram: new indications and dosing for known CYP2C19 poor metabolisers
Fluorouracil: new indication and dose for actinic keratosis
Genital system infections, antibacterial therapy: updated guidance for management of uncomplicated gonorrhoea
Guselkumab: new indications and doses for Crohn’s disease and ulcerative colitis
Herpesvirus infections: updated guidance for post-exposure prophylaxis against chickenpox or shingles
Immunisation schedule: updated guidance
Influenza vaccine (live): update to cautions
Life support algorithm: adult advanced life support algorithm image updated
Liraglutide: monograph updated to incorporate new preparations
Malaria, treatment: updated guidance
Mirikizumab: new indication and dose for Crohn’s disease
Nitrofurantoin: updated indications and dose for prophylaxis of recurrent urinary-tract infection
Ocular corticosteroids and ocular NSAIDs: update to cautions
Posaconazole: update to indications and dose, and important safety information
Prescribing in palliative care: updated guidance for opioid dose conversions
Rasburicase: harm from delayed administration of rasburicase for tumour lysis syndrome [National Patient Safety Alert advice]
Semaglutide (Ozempic®): updated dose equivalence and conversion statement
Semaglutide (Rybelsus®): updated indications and dose for type 2 diabetes mellitus, and important safety information
Trimethoprim: updated indications and dose for prophylaxis of recurrent urinary-tract infection
Ulipristal acetate: updated breast-feeding advice
Vaccination, general principles: updated guidance for vaccines and asplenia, splenic dysfunction, or complement disorders.
BNF is published jointly by BMJ Group and Pharmaceutical Press.