On 1 January 2023, Ontario expanded pharmacists’ scope of practice, allowing them to prescribe medications for 13 minor ailments, including antibiotics for uncomplicated urinary tract infections (UTIs) and Lyme disease (LD) prophylaxis. This study evaluates pharmacist billing claims and pharmacist and physician antibiotic-prescribing rates before and after policy implementation.

An interrupted time series analysis measuring changes in prescribing trends post-implementation.

This retrospective study analysed visit claims and antibiotic prescribing for UTIs and LD prophylaxis before policy implementation (2022) and after (2023–2024) in Ontario.

Data from Ontarians

Prescribing rates were standardised per 1000 inhabitants, stratified by provider type, patient age and sex, and antibiotic type.

In 2023 and 2024, pharmacists submitted over 1.47 million minor ailment claims, with UTIs making up 34.2% and LD prophylaxis making up 2.6% of total claims. UTI claims were primarily for women aged 25–64, and LD prophylaxis peaked in spring and fall. Pharmacist prescribing of eligible urinary drugs in females increased by 33.3 per 1000 person-years (95% CI 30.8 to 36.6) while physician prescribing decreased by 23.3 (95% CI –32.2 to –15.3), leading to a modest net increase of 10.1 (95% CI 0.0 to 18.7). Pharmacist prescribing of doxycycline was offset by decreased physician prescribing, resulting in no change (0.0, 95% CI –1.0 to 0.9). Pharmacist prescribing for other antibiotics was low over the study timeframe, while physician prescribing increased, which was driven by increased prescribing of penicillins and macrolides.

There was a clear increase in pharmacist prescribing for eligible drugs in the eligible population post-policy implementation. Pharmacists in Ontario appear to be prescribing within policy limits for uncomplicated UTIs and LD prophylaxis.