I thought Ketamine was considered a rape-drug and thus prohibited.
Science might be finally gaining the upper hand in the drug war against political forces which won the public opinion battle back in the 70s. It's much harder to convince the public drugs r bad if 95% of the "hard" drugs have medical uses.
[1] https://hilaryagro.wordpress.com/2017/04/12/alright-lets-tal...
Ketamine has substantial legitimate medical uses, and is thus legal in those situations.
It also has a very distinct bitter taste, which would make it quite obvious if someone put it in your drink or similar.
Drugging someone else (wether that be with legal drugs or illegal ones) is allready prohibited, no matter the intent.