Psychopharmacology
December 7, 2022
Adam L. Halberstadt, Dino Luethi, Marius C. Hoener et al.
7 citations
A series of 4-thio-substituted phenylalkylamines, including the psychedelic drugs 2C-T-2 and 2C-T-7, were tested in mice using the head twitch response (HTR), a behavioral proxy for human psychedelic effects. Adding an α-methyl group to the parent compound 2C-T increased potency fivefold, and extending the 4-methylthio group by one to three methylene units also increased potency. Fluorination of the 4-position alkylthio chain or a 4-allylthio substituent reduced activity, and bulky 4-benzylthio groups showed little or no effect. Binding studies confirmed nanomolar affinity for 5-HT2 receptor subtypes and partial agonism at 5-HT2A, supporting classification of these compounds as psychedelic drugs.
European Neuropsychopharmacology
April 1, 2022
Karolina E. Kolaczynska, Paula Ducret, Daniel Trachsel et al.
7 citations
MDA and related amphetamine-based compounds found in street drugs and sport supplements vary in their effects on monoamine transporters and receptors. Most compounds inhibited norepinephrine uptake most potently and preferentially blocked serotonin over dopamine uptake, except 3C-BOH and N,α-DEPEA, which favored dopamine uptake. Several compounds triggered monoamine release, and most bound to serotonin 5-HT2A and 5-HT2C receptors with micromolar affinity, acting as partial or full agonists at 5-HT2A and 5-HT2B. Some also interacted with adrenergic receptors and TAAR1. Fluorinated MDA analogs resembled MDMA's profile, while 3C-BOH and N,α-DEPEA showed amphetamine-like dopaminergic activity. Further pharmacokinetic and pharmacodynamic studies are needed to assess risks and therapeutic potential.
British Journal of Pharmacology
September 6, 2013
Cédric M. Hysek, Yasmin Schmid, Anna Rickli et al.
7 citations
A 125 mg dose of MDMA, a common recreational amount, produces only a moderate increase in body temperature in controlled clinical settings where risk factors like high ambient temperature, physical exertion, and dehydration are avoided. Severe hyperthermia, a rare but life-threatening complication of recreational MDMA use, typically requires additional permissive factors such as repeated or high doses, crowded conditions, or hyperthyroidism. The drug carvedilol, which blocks both α- and β-adrenoceptors, reduced MDMA-induced thermogenesis in humans and reversed established hyperthermia in rats, but its utility for treating severe MDMA toxicity in emergency settings remains unknown and requires further evaluation in case reports or series.
Clinical pharmacology and therapeutics
May 26, 2025
Denis Arikci, Friederike Holze, Lorenz Mueller et al.
6 citations
LSD base and tartrate formulations taken orally are bioequivalent, meaning they produce the same drug levels in the body. The absolute oral bioavailability of LSD is 80%, and all tested oral forms—ethanolic base solution, watery tartrate solution, and rapid-dissolving tablet—show similar pharmacokinetics. Intravenous LSD causes stronger subjective effects like ego dissolution and anxiety compared to oral forms. These findings support interchangeable oral dosing in research and clinical use.
British Journal of Clinical Pharmacology
November 25, 2024
Aaron Klaiber, Mélusine Humbert‐droz, Laura Ley et al.
6 citations
Mescaline doses up to 800 mg appear safe in controlled clinical settings for healthy individuals. In two double-blind, placebo-controlled studies with 48 participants and 96 administrations, positive subjective effects increased with dose and consistently outweighed negative effects. Autonomic effects rose moderately: systolic blood pressure exceeded 180 mmHg in 6% of administrations, heart rate above 100 beats/min occurred in 3%, and body temperature above 38 °C in 5%. Nausea limited higher doses. Kidney and liver function and blood cell counts remained normal. Flashbacks followed 2% of administrations. Adverse effects totaled 51 at 100 mg and 180 at 800 mg.
Drug Testing and Analysis
September 1, 2024
Verena Angerer, Yasmin Schmid, Florian Franz et al.
6 citations
In six healthy volunteers, the new psychoactive substance MDAI at 3.0 mg/kg produced subjective effects comparable to 125 mg of MDMA, including increased blood pressure, but did not raise heart rate or body temperature. MDAI increased cortisol and prolactin levels, appeared in serum about 20 minutes after ingestion, and remained detectable for at least 4 days in serum and 6 days in urine. The drug was well tolerated. Further research is needed to evaluate whether MDAI might have medicinal applications.
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.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
January 1, 2026
Isabelle Straumann, Patrick Vizeli, Isidora Avedisian et al.
5 citations
In a double-blind, placebo-controlled crossover trial with 23 healthy adults, the acute effects of MDMA, its metabolite MDA, and two lysine-conjugated prodrugs were compared. MDA produced stronger and longer-lasting subjective drug effects (6.1 vs. 4.1 hours), greater stimulant effects, more negative effects, fear, and visual alterations than MDMA at equimolar doses. The lysine-conjugated prodrug of MDA (Lys-MDA) delayed the onset and peak of effects but otherwise acted similarly to MDA. Lys-MDMA did not release MDMA into the blood and produced no effects, indicating it is not a functional prodrug. The findings suggest MDA has a less favorable therapeutic profile than MDMA, and lysine conjugation can modulate the timing but not necessarily improve tolerability of effects.
Journal of psychopharmacology (Oxford, England)
December 26, 2025
Kurt Stocker, Matthias Hartmann, Yasmin Schmid et al.
5 citations
A psychometric revalidation of the Altered States of Consciousness Scale (ASC) using data from 901 questionnaires across 16 psychedelic studies (with LSD, psilocybin, mescaline, and DMT) shows that ten of the eleven subscales can be grouped into three higher-order dimensions—Positive Effects, Distressing Effects, and Perceptual Effects—mirroring the original three-dimensional model but with improved statistical fit. The Anxiety subscale could not be integrated due to floor effects (low anxiety in the sample) but is retained for clinical relevance. The revised scale, 3D-ASCr, is recommended for use with classic serotonergic psychedelics.
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.
Current Topics in Behavioral Neurosciences
July 31, 2024
Friederike Holze, Matthias E. Liechti, Felix Müller
4 citations
Psychedelics, including phenethylamines (e.g., mescaline), tryptamines (e.g., psilocybin), and ergolines (e.g., LSD), bind to the serotonin 5-HT2A receptor, causing profound alterations in sensation, cognition, emotions, and self-perception. While generally considered physiologically safe compared to other recreational drugs, they carry risks of lasting psychological adverse reactions such as persisting anxiety, dissociation, or flashbacks. This chapter provides a comprehensive overview of their pharmacology, origins, psychological and autonomic effects, interactions, risks, dosing, and consumption methods, distinguishing them from other psychoactive drugs like MDMA and ketamine based on distinct receptor profiles.
Psychopharmacology
March 26, 2025
Laura Ley, Matthias E. Liechti, Anna M Becker et al.
3 citations
Healthy volunteers enroll in psychedelic trials primarily out of interest in the substances and the appeal of the study setting, hoping for personal development and transformative experiences. In a series of six double-blind, placebo-controlled trials involving 151 participants, positive experiences were promoted by music, access to nature, and a trusting relationship with the investigator. A sterile hospital environment, lack of investigator support, and investigator-induced discomfort were criticized. Most volunteers felt their expectations were exceeded and would take the substances again, ideally in a natural setting with friends. Four key factors for positive study experiences are a secure interpersonal relationship, an aesthetically pleasing environment, access to nature, and music.
Neuroscience Applied
January 1, 2022
Friederike Holze, A. Becker, Karolina E. Kolaczynska et al.
3 citations
No Summary
5-HT2B Receptors
January 1, 2021
Dino Luethi, Matthias E. Liechti
3 citations
Stimulant and psychedelic drugs of abuse interact with monoaminergic systems, and the 5-HT_2B receptor is a relatively understudied target of serotonergic drugs. Activation of this receptor has been demonstrated for benzofuran-class stimulants and substituted amphetamines with a serotonergic profile, and may lead to cardiac valvulopathy. Many psychedelic drugs also activate the 5-HT_2B receptor, but the consequences remain unclear. Cardiac valvulopathy is likely not a concern with occasional psychedelic use, but may differ for microdosing regimens involving daily or multiple-times-weekly low doses.
European Neuropsychopharmacology
April 10, 2026
Deborah Rudin, Jan Valenta, Helene Rolli et al.
2 citations
Serotonergic psychedelics primarily activate the serotonin 2A receptor, but their full effects involve multiple receptor subtypes and signaling pathways. Using stable cell lines and bioassays measuring phospholipase C activation via inositol monophosphate formation, phospholipase A2 activation, β-arrestin2 recruitment, and Gαi-protein dissociation across 5-HT2A, 5-HT2B, 5-HT2C, and 5-HT1A receptors, the study found that inositol monophosphate formation provides the most robust measure of 5-HT2 receptor activation and correlates strongly with known psychoactive doses. Most psychedelics showed signaling bias toward the PLC-IP1 or PLA2-AA pathway at the 5-HT2A receptor. The 5-HT2A/5-HT1A activation ratio may indicate seizure risk and therapeutic potential. Low activation at the 5-HT2B receptor suggests reduced cardiac risk with intermittent use, while strong 5-HT2C receptor activation aligns with low abuse potential.
Endocrine connections
June 1, 2025
Cihan Atila, Sara-Jessica Camerin, Matthias E. Liechti et al.
2 citations
A single oral dose of MDMA (100 mg) strongly activates the hypothalamic-pituitary-adrenal (HPA) axis in healthy adults. Plasma ACTH increased from 12 ng/L to 38 ng/L and cortisol from 347 nmol/L to 566 nmol/L within 120 minutes. Prolactin showed a mild, non-significant change. MDMA did not affect other anterior pituitary hormones (TSH, LH, GH) or their peripheral hormones (fT4, testosterone, estradiol). The findings suggest MDMA may serve as a novel stimulation test for simultaneously assessing the HPA axis and oxytocin systems, but further validation in larger populations is needed.
Frontiers in Psychiatry
January 1, 2025
Peter Gasser, Matthias E. Liechti, Friederike Holze
2 citations
A 64-year-old man with traumatic life experiences and neuropathic pain from chemotherapy was treated with LSD and MDMA. Initial 200 µg LSD doses produced no acute effects, but 400 µg doses led to subjective effects and lasting therapeutic benefits. Switching to MDMA—both high doses (150-175 mg) and repeated low doses (12.5-25 mg)—resulted in marked improvements in neuropathic pain that persisted after treatment stopped. MDMA mini/microdosing has not been widely studied; this case documents benefits of low-dose MDMA for pain disorders, though further research is needed.
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.
Cell Reports Medicine
May 7, 2026
Mihai Avram, Aurore Menegaux, Felix Müller et al.
1 citation
Lysergic acid diethylamide (LSD) may alleviate depression by altering white matter microstructure in the brain, potentially reflecting enhanced neuroplasticity. In a clinical trial of 61 patients with major depressive disorder, those receiving moderate-to-high doses (100 μg then 200 μg) showed increased fractional anisotropy in several white matter tracts, including the internal and external capsule, sagittal stratum, and fornix/stria terminalis. These microstructural changes correlated with improvements in depressive symptoms measured at 2, 6, and 12 weeks. The findings suggest that LSD-induced white matter changes are linked to antidepressant effects.
medRxiv
January 16, 2026
Kristian Larsen, Patrick M. Fisher, Drummond E. Mcculloch et al.
1 citation
Classical psychedelics such as LSD, psilocybin, and mescaline produce distinct changes in brain complexity and entropy that are not seen with stimulants like MDMA or d-Amphetamine. Using resting-state fMRI data from three placebo-controlled crossover trials with 79 participants across 255 sessions, the study found that psychedelics specifically increased meta-state complexity, short-timescale multiscale entropy, and dynamic conditional correlation entropy. Both drug classes increased Lempel-Ziv and spatial complexity and decreased absolute modularity, but only psychedelics showed these unique complexity and entropy increases. These findings suggest that psychedelic-specific brain signal changes may help distinguish the acute psychedelic state from other psychoactive drug effects and could be relevant to understanding their therapeutic potential.
Frontiers in Pharmacology
November 20, 2025
Karolina E. Kolaczynska, Daniel Trachsel, Marius C. Hoener et al.
1 citation
A class of psychedelic compounds called 4-substituted 2,6-dimethoxyphenethylamines and their amphetamine counterparts (Ψ derivatives) were tested for their interactions with monoamine receptors and transporters. These derivatives showed moderate to high affinity and activity at the human 5-HT2A receptor, the primary target for psychedelics, with binding affinities ranging from 8 to 1,600 nM and activation potencies from 32 to 3,400 nM. They acted as partial agonists at this receptor. The phenethylamine derivatives also bound to 5-HT1A and 5-HT2C receptors with moderate affinity, while amphetamine derivatives had weaker affinities. Some Ψ derivatives interacted with TAAR1 and adrenergic receptors. Compared to 2,4,5-trisubstituted derivatives, the 2,4,6-trisubstituted Ψ derivatives were generally less potent at the 5-HT2A receptor but more potent than 3,4,5-trisubstituted derivatives.
Molecular Psychiatry
November 5, 2025
Dino Luethi, Grant C. Glatfelter, Eline Pottie et al.
1 citation
Psychedelic-like effects of ring-substituted amphetamines are primarily mediated by 5-HT 2A receptors. Small lipophilic substituents at the 4-position of 2,5-dimethoxyamphetamine enhance clinical potency. This study examined 4-alkylated 2,5-dimethoxyamphetamines (methyl, ethyl, propyl, butyl, amyl) for in vitro receptor activity and in vivo effects in mice using the head-twitch response (HTR) assay. Increasing 4-alkyl chain length raised affinity at 5-HT 2A receptors. The 4-propyl analog showed the highest potencies for 5-HT 2A receptor activation (1–9 nM) in vitro; other chain lengths ranged from 2–56 nM. In mice, maximal HTR counts varied from 23 to 119, with potencies from 0.42 to 2.76 mg/kg.
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.
Clinical toxicology (Philadelphia, Pa.)
March 1, 2025
Joep J. J. Ouwerkerk, David M Wood, Alison M. Dines et al.
1 citation
When 3,4-methylenedioxymetamfetamine (MDMA) is taken with alcohol, emergency department visits show higher odds of agitation, drowsiness, and vomiting compared to MDMA alone. Co-intoxication with other substances increases odds of bradycardia, psychosis, and coma. Mortality rates remain low across all groups. Female patients report less chest pain but more vomiting, headache, and hypotension than males. These variations suggest that physicians should consider both the type of co-intoxication and patient sex to optimize treatment.