I never went when we were in Kanchanaburi, but a friend spoke extensively with a British vet there, who said the tigers were not drugged. She said there were issues with the breeding as it was uncontrolled, across species and that there was too much inbreeding.
I did view, without paying to go in, the tiger world in Chiang Mai. I couldn't understand how they could have so many in such small cages. More than at the temple where I do think they meant well I wonder how these purely commercial places are allowed.