Patients' care is being put at risk because many GP surgeries around the country are playing catch up with prescriptions, experts warn. British researchers found a quarter of practices took around two-and-a-half years to switch to new treatments. A small number of surgeries (10 per cent) took 32 months to start prescribing the new drugs. Experts say the variation is an avoidable waste of NHS money that exposes patients to 'sub-optimal' care. The research team from the University of Oxford looked at more than 8,000 GP surgeries in England. Using the database OpenPrescribing.net, they analysed how the quickly practices responded to two treatment switches over a five-year period. The first was a shift to the generic female contraceptive pill desogestrel, previously sold under the brand name Cerazette, in 2012. The second was to change the first line antibiotic for treating uncomplicated urinary tract infection (UTI) from trimethoprim to nitrofurantoin in 2014. Considerable variation was found between practices in both the timing and how rapidly change was implemented once it had begun. While the majority of practices began to shift away by Cerazette by early 2013, a quarter did not show substantial change for 14 months. A small amount (10 per cent) of practices took at least a further six more months. The move to desogestrel was projected to save the NHS £10million. But because some practices were so slow to implement the change, the health service was exposed to avoidable costs, the researchers note. For antibiotics, a quarter of practices did not make their largest change until 29 months after the guidance was released.