Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
October 1, 2023
Laura Ley, Friederike Holze, Denis Arikci et al.
127 citations
At equally strong doses, the classic psychedelics mescaline, LSD, and psilocybin produce comparable subjective experiences, with no evidence of qualitative differences in altered states of consciousness. Autonomic effects were moderate; psilocybin increased diastolic blood pressure more than LSD, while LSD showed a trend toward higher heart rate than psilocybin. Mescaline had the longest effect duration (mean 11.1 hours), followed by LSD (8.2 hours) and psilocybin (4.9 hours). Mescaline and LSD, but not psilocybin, raised circulating oxytocin. None altered brain-derived neurotrophic factor. Tolerability was similar, though mescaline caused slightly more subacute adverse effects 12–24 hours later.
Frontiers in Pharmacology
April 29, 2024
Jan Thomann, Oliver V Stoeckmann, Deborah Rudin et al.
52 citations
Psilocybin is rapidly converted to psilocin in the body, which causes psychedelic effects by binding to the 5-HT2A receptor. Psilocin is mainly broken down by glucuronidation or conversion to 4-hydroxyindole-3-acetic acid (4-HIAA). In laboratory experiments with human liver microsomes, about 29% of psilocin was metabolized, while specific enzymes CYP2D6 and CYP3A4 metabolized nearly 100% and 40%, respectively. Monoamine oxidase A produced small amounts of 4-HIAA and 4-hydroxytryptophol (4-HTP), but 4-HTP appeared only in lab tests and neither metabolite showed activity at serotonin receptors. Two new potential metabolites were found: norpsilocin in mice and an oxidized form in humans, though CYP2D6 genotype did not affect psilocin levels in people. These findings help understand drug interactions and psilocybin's therapeutic use.
International Journal of Molecular Sciences
July 31, 2021
Karolina E. Kolaczynska, Jan Thomann, Marius C. Hoener et al.
35 citations
Pyrovalerone cathinones, a class of potent psychoactive substances, were tested for their effects on monoamine transporters and receptors. All tested compounds strongly inhibited the dopamine and norepinephrine transporters, with IC50 values in the low micromolar range, but showed no activity at the serotonin transporter at concentrations below 10 µM. None of the substances triggered monoamine efflux. Two compounds, 4F-PBP and NEH, were particularly selective for the dopamine transporter, suggesting they likely produce strong psychostimulant effects and have high abuse potential. Extending the alkyl chain increased inhibition potency at dopamine and norepinephrine transporters, while a 3,4-methylenedioxy group enhanced serotonin transporter inhibition.
Translational psychiatry
September 30, 2024
Aaron Klaiber, Yasmin Schmid, Anna M Becker et al.
27 citations
Mescaline produces dose-dependent subjective and physiological effects in healthy people, with doses above 100 mg increasing blood pressure and heart rate. Subjective effects lasted from 6.4 hours at 100 mg to 14 hours at 800 mg, and the drug reached peak concentration in blood after about 2 hours with a half-life of 3.5 hours. Nausea and vomiting were common at the highest dose. Blocking serotonin 5-HT2A receptors with ketanserin reduced the effects of 800 mg mescaline to levels similar to lower doses, indicating that mescaline's acute effects are primarily mediated by these receptors.
Journal of Pharmaceutical and Biomedical Analysis
August 1, 2022
Jan Thomann, Laura Ley, Aaron Klaiber et al.
23 citations
A bioanalytical method using ultra-high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and validated to rapidly quantify mescaline and its metabolites (TMPAA, NAM, and 4-desmethyl mescaline) in human plasma. The single-step protein precipitation extraction achieved complete recovery (≥98.3%) with minor matrix effects (≤7.58%). Intra-assay accuracy ranged from 84.9% to 106%, and precision was ≤7.33%. The method's sensitivity allowed lower limits of quantification of 12.5 ng/mL for mescaline and TMPAA, and 1.25 ng/mL for NAM, sufficient for clinical pharmacokinetic studies. However, 4-desmethyl mescaline could not be selectively quantified due to interference from another metabolite. The method is reliable and easy-to-use for forensic and clinical pharmacokinetic applications.
Clinical Pharmacology & Therapeutics
February 28, 2025
Lorenz Mueller, Alen Jelušić, Avram Tolev et al.
15 citations
In a double-blind, placebo-controlled crossover study with 23 healthy participants, daily paroxetine (an SSRI antidepressant) did not reduce the pleasant subjective effects of a single 100 μg dose of LSD, but it significantly lessened negative effects such as 'bad drug effect,' anxiety, and nausea. Paroxetine increased LSD's peak concentration and total exposure by 40% and 50%, respectively, by inhibiting the CYP2D6 enzyme, indicating this enzyme is involved in LSD metabolism. The interaction was strongest in normal CYP2D6 metabolizers and weakest in poor metabolizers. The findings suggest LSD can be safely added to SSRI treatment without dose adjustment when the SSRI inhibits CYP2D6, but no definitive recommendation can be made for other SSRIs.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences
May 1, 2024
Dino Luethi, Deborah Rudin, Isabelle Straumann et al.
6 citations
Two bioanalytical methods—achiral and enantioselective—were developed and validated to measure MDMA and its metabolite MDA in human plasma. Both methods met regulatory guidelines for accuracy, precision, selectivity, and sensitivity over calibration ranges of 0.5–500 ng/mL (achiral) and 0.5–1,000 ng/mL (chiral). The enantioselective method reliably quantified individual enantiomers in racemic samples, and racemic calibrations accurately measured single-enantiomer samples. Pharmacokinetic parameters from clinical participants treated with racemic MDMA or a single enantiomer were comparable between methods. Because MDMA and MDA do not undergo chiral inversion, enantioselective separation is unnecessary when only one enantiomer is administered.
Clinical pharmacokinetics
July 14, 2025
Lorenz Mueller, Aaron Klaiber, Laura Ley et al.
4 citations
Mescaline, a classic psychedelic, shows dose-proportional increases in blood concentration and effects after oral administration. Peak levels occur within about 2 hours, with a half-life of 3.5 hours. Effects begin around 1 hour after dosing, with intensity and duration increasing from 13% and 2.8 hours at 100 mg to 89% and 15 hours at 800 mg. About 53% of the dose is excreted unchanged in urine, and 31% as a main metabolite. Oral bioavailability is at least 53%, limited by first-pass metabolism, with renal elimination as the primary clearance route.
Drug metabolism and disposition: the biological fate of chemicals
April 28, 2025
Jan Thomann, Deborah Rudin, Selina Kraus et al.
4 citations
A liquid chromatography-tandem mass spectrometry method was developed and validated to measure the recreational psychedelic 2C-B and two of its metabolites (BDMPAA and B-2-HMPAA) in human plasma. The method achieved linear ranges of 0.5–100 ng/mL for 2C-B, 2.5–1000 ng/mL for BDMPAA, and 0.5–1000 ng/mL for B-2-HMPAA with high accuracy and precision. Pharmacokinetic analysis used samples from clinical participants who received 30 mg of 2C-B. Key metabolic enzymes included MAO-A, MAO-B, cytosolic enzymes, and CYP2D6. Unlike 2C-B, the metabolites did not activate the serotonin 2A receptor, indicating they do not contribute to the psychedelic effect. The method provides a reliable tool for future clinical studies.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
July 1, 2026
Denis Arikci, Joran Borgulya, Isabelle Straumann et al.
1 citation
In a double-blind, randomized, placebo-controlled crossover trial, 24 healthy adults received three doses of 2C-B (10, 20, and 30 mg), 125 mg MDMA, and 25 mg psilocybin. The 30 mg dose of 2C-B produced subjective effects comparable to MDMA but weaker than psilocybin, and increased emotional empathy similarly to MDMA. Only psilocybin caused bad drug effects and anxiety. MDMA produced the greatest cardiovascular stimulation, followed by psilocybin and then 2C-B. Only MDMA raised plasma oxytocin and neurophysin I. The average subjective effect duration of 30 mg 2C-B was 4.9 hours, similar to MDMA (4.8 h) and shorter than psilocybin (6.1 h). 2C-B had a plasma elimination half-life of about 1.3 hours.
Biomedical chromatography : BMC
September 1, 2025
Jan Thomann, Selina Kraus, Livio Erne et al.
1 citation
A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method accurately measures ketamine and its metabolites norketamine, dehydronorketamine (DHNK), and (2R,6R)-hydroxynorketamine (HNK) in human plasma. The method uses a small sample volume, a simple protein precipitation step, and a fast run time. Linear quantification ranges were 1-1,000 ng/mL for ketamine and norketamine, 0.25-100 ng/mL for DHNK, and 2.5-1,000 ng/mL for (2R,6R)-HNK. The method showed high accuracy, precision, selectivity, and sensitivity, with consistent matrix effects and efficient extraction recovery. It was successfully applied to assess pharmacokinetics in six clinical trial participants, offering a robust approach for clinical studies, drug monitoring, and forensic investigations.