We've been doing battle with our surgery too. Mrs DW is on meds and she requests her refills with seven days notice. The surgery is post dating the prescription so it isn't sent to the chemist until the day she runs out of the current dose.
And what happens if I'm at work and she can't get out the house that day? Or the pharmacy hasn't got any?
She's on Pregabalin which is an anti convulsant and missing one dose can have pretty horrendous side effects, Venlafaxine which
@catfishwolf described the side effects of above and propranolol.
Their attitude is so blase "well the side effects shouldn't be that bad if you miss one" well get fucked pal because the reality is wholly different.