In the movie Fear and loathing in Las Vegas, Thorazine is suggested as an antidote to an overly intense psychedelic experience.
In common knowledge today, a Xanax or benzodiazapine is suggested to calm the nerves.
Low dose lithium may have an anti-dopaminergic effect (which has been implicated in the 2nd phase of the LSD experience).
CBD
https://www.erowid.org/psychoactives/pharmacology/images/pharmacology_article2-6-med.png
