Trial reportThe international journal of neuropsychopharmacology2023
Ketanserin Reverses the Acute Response to LSD in a Randomized, Double-Blind, Placebo-Controlled, Crossover Study in Healthy Participants.
Trial report in The international journal of neuropsychopharmacology, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT04558294 (Effect of Ketanserin After LSD Administration on the Acute Response to LSD in Healthy Subjects), which is not on this map. Cited by 58 papers, 4 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Effect of Ketanserin After LSD Administration on the Acute Response to LSD in Healthy Subjects
Who cites it
58 citing papers in PubMed, 4 syntheses or guidelines pooled it, 91 citations in OpenAlex.
- A systematic review of the pharmacokinetics of classical serotonergic psychedelic compounds in healthy adult subjects.Journal of psychopharmacology (Oxford, England) · 2026Pooled it
- Effects of psychoplastogens on blood levels of brain-derived neurotrophic factor (BDNF) in humans: a systematic review and meta-analysis.Molecular psychiatry · 2025Pooled it
- Drug-drug interactions involving classic psychedelics: A systematic review.Journal of psychopharmacology (Oxford, England) · 2024Pooled it
- Dose-response relationships of LSD-induced subjective experiences in humans.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2023Pooled it
- The 3D-ASCr scale: A revalidation of the core dimensions of the Altered States of Consciousness Rating Scale 5D(11)-ASC for psychedelic research.Journal of psychopharmacology (Oxford, England) · 2026Trial
- Pharmacokinetics, Pharmacodynamics, and Urinary Recovery of Oral Mescaline Hydrochloride in Healthy Participants.Clinical pharmacokinetics · 2025Trial
- Absolute Oral Bioavailability and Bioequivalence of LSD Base and Tartrate in a Double-Blind, Placebo-Controlled, Crossover Study.Clinical pharmacology and therapeutics · 2025Trial
- Motivation and retrospective appraisal of psychedelic study participation: a qualitative study in healthy volunteers.Psychopharmacology · 2025Trial
- Acute Effects and Pharmacokinetics of LSD after Paroxetine or Placebo Pre-Administration in a Randomized, Double-Blind, Cross-Over Phase I Trial.Clinical pharmacology and therapeutics · 2025Trial
- Acute dose-dependent effects of mescaline in a double-blind placebo-controlled study in healthy subjects.Translational psychiatry · 2024Trial
- Pharmacological and non-pharmacological predictors of the LSD experience in healthy participants.Translational psychiatry · 2024Trial
- Effects of discontinuation of serotonergic antidepressants prior to psilocybin therapy versus escitalopram for major depression.Journal of psychopharmacology (Oxford, England) · 2024Trial
- Acute effects of MDMA and LSD co-administration in a double-blind placebo-controlled study in healthy participants.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2023Trial
- Acute effects of intravenous DMT in a randomized placebo-controlled study in healthy participants.Translational psychiatry · 2023Trial
- Spatial Collinearity Constrains Multivariate Molecular-Enriched Network Estimation.Human brain mapping · 2026Article
- Deconstruction of lysergic acid diethylamide.Proceedings of the National Academy of Sciences of the United States of America · 2026Article
- Resetting the hippocampal buffer: a neurocognitive account of psychedelic therapy for anxiety-related psychopathology.Psychopharmacology · 2026Review
- Article
- Psychedelics produce enduring enhancement of reward responsiveness in male rats.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2026Article
- The working lives of neuronal 5-HTRSC chemical biology · 2026Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
8 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundLysergic acid diethylamide (LSD) is currently being investigated in psychedelic-assisted therapy. LSD has a long duration of acute action of 8-11 hours. It produces its acute psychedelic effects via stimulation of the serotonin 5-hydroxytryptamine-2A (HT2A) receptor. Administration of the 5-HT2A antagonist ketanserin before LSD almost fully blocks the acute subjective response to LSD. However, unclear is whether ketanserin can also reverse the effects of LSD when administered after LSD.
methodsWe used a double-blind, randomized, placebo-controlled, crossover design in 24 healthy participants who underwent two 14-hour sessions and received ketanserin (40 mg p.o.) or placebo 1 hour after LSD (100 µg p.o.). Outcome measures included subjective effects, autonomic effects, acute adverse effects, plasma brain-derived neurotrophic factor levels, and pharmacokinetics up to 12 hours.
resultsKetanserin reversed the acute response to LSD, thereby significantly reducing the duration of subjective effects from 8.5 hours with placebo to 3.5 hours. Ketanserin also reversed LSD-induced alterations of mind, including visual and acoustic alterations and ego dissolution. Ketanserin reduced adverse cardiovascular effects and mydriasis that were associated with LSD but had no effects on elevations of brain-derived neurotrophic factor levels. Ketanserin did not alter the pharmacokinetics of LSD.
conclusionsThese findings are consistent with an interaction between ketanserin and LSD and the view that LSD produces its psychedelic effects only when occupying 5-HT2A receptors. Ketanserin can effectively be used as a planned or rescue option to shorten and attenuate the LSD experience in humans in research and LSD-assisted therapy. TRIAL REGISTRY: ClinicalTrials.gov (NCT04558294).
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.