Effect of Ketanserin After LSD Administration

LSD (lysergic acid diethylamide) is a serotonergic (5-HT) hallucinogen widely used for recreational and/or ethnomedical purposes. LSD is thought to induce its prototypical psychedelic effects primarily via stimulation of the 5-HT2A receptor.

This study investigates whether an LSD experience can be attenuated and shortened using 5-HT2A receptor antagonist ketanserin administration after LSD once the psychedelic effects have established.

Topic Healthy Subjects
Compound Placebo LSD
Country Switzerland
Visit trial
Status Completed
Results Published Yes
Start date 16 October 2020
End date 29 September 2021
Chance of happening 100%
Phase Phase I
Design Blinded
Type Interventional
Generation First
Participants 24
Sex All
Age 25- 65
Therapy No

Trial Details

LSD is a so-called "classic" or serotonergic hallucinogen or psychedelic.The effects of LSD have been frequently investigated in the past in both healthy participants and patients. In these studies, LSD produced acute transient alterations in waking consciousness including visual perceptual alterations, audio-visual synesthesia, derealization and depersonalization. Moreover, several of these studies described robust and sustained effects of LSD in patients suffering from addiction, anxiety and depression. Its psychedelic effects are mainly attributed to its potent partial 5-HT2A receptor agonism. Consistently, administration the 5-HT2A receptor antagonist ketanserin (40 mg) prior to the administration of LSD (100 μg) almost completely prevented the acute effects of LSD in another study of our research group (NCT03321136). The present study hypothesis is that ketanserin (40 mg) administered 1h after LSD shortens and reduces the acute subjective effects of LSD (100 μg) compared to LSD alone (100 μg) followed by placebo in healthy humans. Such a finding would confirm a primarily competitive antagonism of ketanserin and LSD at the 5-HT2A receptor in vivo and indicate that LSD produces its psychedelic effects only when present at the receptor.

NCT Number NCT04558294

Sponsors & Collaborators

University of Basel
The University of Basel Department of Biomedicine hosts the Liechti Lab research group, headed by Matthias Liechti.

MindMed
MindMed is one of the largest companies in the psychedelics space and is developing various psychedelics for mental health disorders.

Papers

Ketanserin reverses the acute response to LSD in a randomized, double-blind, placebo-controlled, crossover study in healthy subjects
This double-blind, placebo-controlled study (n=24) finds that ketanserin (40mg) administered one hour after LSD (100µg) reversed the effects cutting down the trip from an average of 8.5 to 3.5 hours. This is the first study to show that ketanserin can effectively stop/halt an ongoing psychedelic trip.

Data attribution

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