Clinical TrialHealthy VolunteersLSDPlaceboLSDCompleted

Effect of Ketanserin After LSD Administration

Double-blind, randomised, 2-period crossover in healthy adults (n=24) testing whether ketanserin 40 mg given 1 hour after 100 µg LSD shortens and attenuates acute subjective LSD effects.

Target Enrollment
24 participants
Study Type
Phase I interventional
Design
Randomized, triple Blind

Detailed Description

This double-blind, random-order, two-period crossover study in healthy volunteers compares 100 µg LSD followed by ketanserin 40 mg versus 100 µg LSD followed by placebo to assess whether post-hoc 5-HT2A antagonism shortens and reduces psychedelic effects.

Primary purpose is basic science: to probe competitive antagonism at the 5-HT2A receptor and characterise acute subjective and physiological effects. Outcomes include subjective ratings, safety measures and pharmacodynamic observations.

Study Protocol

Preparation

sessions

Dosing

2 sessions

Integration

sessions

Study Arms & Interventions

LSD + ketanserin placebo

experimental

100 µg LSD with ketanserin placebo (mannitol)

Interventions

  • LSD100 µg
    via Oral• single dose

    Single 100 µg LSD dose

  • Placebo
    via Oral• single dose

    Ketanserin placebo (mannitol)

LSD + ketanserin (40 mg)

experimental

100 µg LSD with oral ketanserin 40 mg

Interventions

  • LSD100 µg
    via Oral• single dose

    Single 100 µg LSD dose

  • Compound40 mg
    via Oral• single dose

    Ketanserin 40 mg administered 1 hour after LSD

Participants

Ages
25 – 65
Sexes
Male & Female

Inclusion Criteria

  • Age between 25 and 65 years old
  • Sufficient understanding of the German language
  • Understanding of procedures and risks associated with the study
  • Willing to adhere to the protocol and signing of the consent form
  • Willing to refrain from the consumption of illicit psychoactive substances during the study
  • Abstaining from xanthine-based liquids and foods from the evenings prior to the study sessions to the end of the study days
  • Willing not to operate heavy machinery within 48 hours after substance administration
  • Willing to use double-barrier birth control throughout study participation
  • Body mass index between 18-29 kg/m2

Exclusion Criteria

  • Chronic or acute medical condition
  • Current or previous major psychiatric disorder
  • Psychotic disorder or bipolar disorder in first-degree relatives
  • Hypertension (>140/90 mmHg) or hypotension (SBP<85 mmHg)
  • Hallucinogenic substance use (not including cannabis) more than 20 times or any time within the previous two months
  • Pregnancy or current breastfeeding
  • Participation in another clinical trial (currently or within the last 30 days)
  • Use of medication that may interfere with the effects of the study medication
  • Tobacco smoking (>10 cigarettes/day)
  • Consumption of alcoholic beverages (>20 drinks/week)

Study Details

  • Status
    Completed
  • Phase
    Phase I
  • Type
    interventional
  • Design
    Randomizedtriple Blind
  • Target Enrollment24 participants
  • Timeline
    Start: 2020-10-16
    End: 2021-09-29
  • Compounds
    LSDPlaceboLSD
  • Topic
    Healthy Volunteers

Locations

Clinical Pharmacology & Toxicology, University Hospital Basel — Basel, Switzerland

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