The Molecule That Nearly Became LSD - Silenced by Nausea

The Molecule That Nearly Became LSD - Silenced by Nausea In this episode, we tell the story of quipazine from its 1966 discovery through human trials and animal experiments, tracing why it was classified as antidepressant-like and then abandoned - and asking whether the nausea problem closed a door science has not yet reopened. Person: anonymous human volunteers Date: 1966 (first description) Compound: quipazine (one-2-quinolinyl-piperazine; “two-QP”) Dose: 25 mg oral caused significant gastrointestinal distress Receptor profile: potent 5-HT3 agonist; agonist at 5-HT2A/2B/2C; inhibits serotonin reuptake - Quipazine was first described in 1966 and later labeled antidepressant-like by 1971. - Oral doses of 25 mg in humans produced significant nausea, vomiting, cramping, flatulence and diarrhea. - Quipazine is a 1-(2-quinolinyl)-piperazine (also called two-QP) synthesized from 2-chloroquinoline and piperazine. - In rodents and monkeys quipazine produced the head-twitch response characteristic of classical psychedelics. - In drug discrimination studies, rats fully substituted quipazine for LSD, indicating indistinguishable drug-state effects in that model. To listen to this podcast ad-free and access premium episodes, try our subscription with a 14-day free trial at obomedia.com. © 2026 OBOMEDIA. All rights reserved. This episode and its content (audio, text, and related materials) are the exclusive property of OBOMEDIA and are protected by applicable copyright laws. Reproduction, distribution, editing, or commercial use, in whole or in part, without prior written permission from OBOMEDIA is prohibited. For permissions, licensing, and business inquiries: [email protected].