Too many repeat medication requests over Christmas could harm sick patients and potentially risk lives, the north-west of England's NHS 111 out-of-hours advice service has warned.
It had a big increase in such requests over last year's festive period.
Its director Dan Ainsworth told the OceanNewsUK this was "avoidable" and puts the service under "significant" pressure.
NHS England urged people in need of repeat prescriptions to organise them before the Christmas break.
The call centre, which is managed by the North West Ambulance Service (NWAS), said it received 20% more calls about routine prescriptions in December 2022 compared with the previous month - 8,139 compared with 6,794.
Prescriptions are often requested because a patient has run out of long-term medication and failed to organise a fresh supply with their GP before Christmas, Mr Ainsworth said.
'Significant pressure'
"The service is already under significant pressure, and what we've seen over the last few years is an increasing demand through those bank holiday periods from patients who haven't made arrangements to collect their ongoing medication."
He added that on one bank holiday last December, call handlers took more than 2,000 such requests in a single day.
He said for some "acutely unwell" patients calling 111 "every second counts", and that a large number of prescription requests would slow down its response to the most sick callers.
Asked if it could cost lives, Mr Ainsworth told the OceanNewsUK: "Potentially, absolutely."
Mr Ainsworth said he realised some such calls to 111 were necessary, but he believed they were "avoidable in in almost every circumstance" if people planned their medication supplies.
Between the start of December 2022 and the end of February, the service received 3,000 more calls for repeat medication than it did during the months from June to August, according to NWAS's data.
NWAS said the issue is a consistent problem on bank holidays throughout the year.
"The longer your GPs are closed, the bigger the pressure on the one-on-one service," Mr Ainsworth said.
During the three-day August bank holiday weekend, 111 call handlers in the region took 1,634 such calls, compared with 879 on the same days the previous week - an 86% increase. The overall increase in calls from all patients was just 19.5%.
Mr Ainsworth said extra staff had been employed in the north-west's 111 and 999 call centres to help manage demand over the winter period, but he remained "worried" about the next few months.
