There are some beer stalls that get set up on Suk that serve spiked drinks, I posted on one about two years ago.
In my case when I started feeling woozy I got up, left the stall and went immediately to my hotel room. All I ended up with is a nasty headache from the 'mickey' they slipped me.
I haven't seen any of these type operations out there lately.
But to echo the Duck, never leave a drink unattended and make sure they open the beer bottle in front of you.