To describe trends and geographical variation in prescribing of trimethoprim and nitrofurantoin to treat urinary tract infections, to describe variation in implementing guideline change and to compare actions taken to reduce trimethoprim use in high- and low-using Clinical Commissioning Groups (CCGs).


A retrospective cohort study and interrupted time series analysis of English NHS primary care prescribing data, complemented by information obtained through Freedom of Information Act requests to CCGs. The main outcome measures were variation in practice and CCG prescribing ratios geographically and over time, including an interrupted time series, and responses to Freedom of Information requests.


The amount of trimethoprim prescribed, as a proportion of nitrofurantoin and trimethoprim combined, remained stable and high until 2014, then fell gradually to <50% in 2017; this reduction was more rapid following the introduction of the ‘Quality Premium’. There was substantial variation in the speed of change between CCGs. As of April 2017, for the 10 CCGs with the lowest trimethoprim ratios, 9 had reported at least one of: formulary change, work plan or incentive scheme to change prescribing behaviour. None of the 10 highest-ratio CCGs did so.


Many CCGs failed to implement an important change in antibiotic prescribing guidance, and there is strong evidence suggesting that CCGs with minimal prescribing change did little to implement the new guidance. We recommend: (i) a national programme of training and accreditation for medicines optimization pharmacists; and (ii) remedial action for CCGs that fail to implement guidance—with all materials and data shared publicly for both such activities.