So sorry this happened to your DD - it must have been stressful and scary and really impacted her enjoyment of herb night out. My DD has an allergy to pineapple managed with antihistamines and that's scary enough!
The way the club managed your DDs requirements doesn't seem great, however I want to give another view
3 weeks ago I got a call in the ealy hours that DD had been needle spiked in a club. She's at uni 240 miles away. She had 3 needle marks in her thigh, police involved and uni welfare team (it was a uni student only club night). We didn't know how common this horror is before this happened. She had no idea anything had happened the next morning until her BF asked how she was feeling. Police were amazing and at no point tried to attribute to alcohol etc.
It was a very traumatic and scary event for everyone. Luckily, DD has amazing uni friends who, even though they'd been drinking, acted quickly and(sort of) competently. The police have obviously dealt with this many times and had processes in place, including taking statements at uni halls (DD was interviewed in her room with a friend present). The club have been so helpful with CCTV, and police and uni to try to identify the horrible fked up person who did this.
We had frank and honest discussions with club manager and police - this is, sadly, not uncommon (they chose their words carefully...) and becoming more common and incidents identified as club staff, police, victims and people with victims become more aware of symptoms (previously put down to having drunk too much or taking drugs).
The club has a policy of no medication inside - it's all taken, bagged and labelled. There are 'welfare staff' around the club with orange vis top and processes in place.
It's been a massive psychological mindfk. DD is an convinced 10s if not 100s of women are assaulted or raped every week using these drugs - she had no recollection whatsoever, lost 12 hours of her life. She she couldn't walk, was babbling, incoherent and was completely incapacitated. The favt that she couldn't remember any of that is what's freaking her out the most.
I'm not sure what the solution is to ensure everyone's safety but personally, if I'm honest, I'd be more comfortable knowing there are no syringes or needles in clubs and bars.