Drug Testing and Analysis
January 1, 2012
Steven A. Barker, Ethan H. Mcilhenny, Rick J. Strassman
143 citations
Three indole alkaloids with varying psychedelic activity—DMT, bufotenine, and 5-MeO-DMT—have been reported as naturally occurring in humans. A critical review of 69 studies from 1955 to 2010 examined their detection in blood, urine, and cerebrospinal fluid. The review evaluates the methods and criteria used, highlighting strengths and weaknesses of past approaches. It notes shortcomings in existing data given recent findings and suggests future directions for research on these endogenous psychedelics.
Journal of Clinical Psychopharmacology
October 15, 2011
Rafael G. Dos Santos, Marta Valle, José Carlos Bouso et al.
136 citations
Ayahuasca, an Amazonian psychotropic tea containing DMT and β-carboline alkaloids, produced moderate sympathomimetic effects, significant increases in prolactin and cortisol, and time-dependent changes in immune cell populations in a double-blind crossover trial with 10 healthy volunteers. Pupil dilation occurred with both ayahuasca and amphetamine, but ayahuasca’s effects were milder. Prolactin rose only after ayahuasca, while cortisol peaked higher with ayahuasca than with amphetamine. Lymphocyte subsets shifted similarly for both drugs: CD4 and CD3 percentages decreased, and natural killer cells increased, with maximum changes at 2 hours and return to baseline by 24 hours.
Drug Testing and Analysis
July 28, 2014
Jordi Riba, Ethan H. Mcilhenny, José Carlos Bouso et al.
96 citations
When N,N-dimethyltryptamine (DMT) is taken orally, it produces no psychedelic effects and no DMT appears in urine, because monoamine oxidase (MAO) breaks it down almost completely into indole-3-acetic acid (97% of recovered compounds). By contrast, smoking DMT yields full psychoactivity, with unmetabolized DMT and DMT-N-oxide rising to 10% and 28% of recovered compounds, while indole-3-acetic acid drops to 63%. An inverse relationship between the ratio of these metabolites and subjective effects indicates that smoking shifts metabolism from efficient MAO-dependent breakdown to less efficient CYP-dependent pathways, enabling psychoactivity.
Drug Testing and Analysis
April 19, 2012
Jordi Riba, Ethan H. Mcilhenny, Marta Valle et al.
91 citations
Ayahuasca, an Amazonian tea containing β-carboline alkaloids (harmine, harmaline, tetrahydroharmine) and the psychedelic DMT, is used worldwide, but its metabolism in humans had not been systematically studied. In 10 healthy men given freeze-dried ayahuasca (1.0 mg DMT/kg), less than 1% of DMT was excreted unchanged; about 50% was recovered as indole-3-acetic acid, 10% as DMT-N-oxide, and total DMT plus metabolites reached 68%. Harmala alkaloids were excreted as O-demethylated and conjugated metabolites, but recoveries varied from 9% to 65%. The findings indicate alternative metabolic routes for DMT beyond monoamine-oxidase and that O-demethylation plus conjugation is important but not the only pathway for harmala alkaloids.
Journal of chromatography. A
December 18, 2009
Ethan H. Mcilhenny, Kelly E Pipkin, Leanna J Standish et al.
58 citations
A new analytical method using direct injection and liquid chromatography-tandem mass spectrometry can simultaneously measure 11 psychoactive compounds in ayahuasca, a plant-based Amazonian beverage used in traditional medicine and religious ceremonies. The technique uses a deuterated internal standard for accurate quantitation and requires only simple dilution of samples up to 200-fold, avoiding complex extraction steps. It shows high specificity, low detection and quantitation limits, and appears to eliminate matrix effects. The method was tested on three different ayahuasca preparations and is expected to aid clinical, ethnobotanical, and forensic studies.
Biomedical chromatography : BMC
March 1, 2012
Ethan H. Mcilhenny, Jordi Riba, Manel J. Barbanoj et al.
57 citations
A new single analytical method can directly measure 14 major alkaloid components of ayahuasca, including known and potential metabolites of N,N-dimethyltryptamine and harmala alkaloids, in human blood plasma. The method uses 96-well plate protein precipitation and filtration followed by HPLC-ion trap-ion trap-mass spectrometry with heated electrospray ionization to reduce matrix effects. It provides adequate sensitivity, specificity, and reproducibility for clinical research, expanding the list of compounds that can be monitored after ayahuasca administration while simplifying the analysis compared to previous combined techniques.
Biomedical chromatography : BMC
September 1, 2011
Ethan H. Mcilhenny, Jordi Riba, Manel J. Barbanoj et al.
51 citations
The primary metabolite of N,N-dimethyltryptamine (DMT) in humans after ayahuasca ingestion is the corresponding N-oxide, the first time this metabolite has been described in in vivo human studies. Very little DMT was detected in urine, despite monoamine oxidase inhibition by harmala alkaloids. The major harmala alkaloid excreted was tetrahydroharmine. A rapid, sensitive method using HPLC-electrospray ionization-selected reaction monitoring-tandem mass spectrometry was developed and applied to urine samples from three individuals administered ayahuasca, identifying and quantifying major constituents and metabolites. The protocol is suitable for toxicological and clinical research on ayahuasca.
June 8, 2012
Ethan H. Mcilhenny
1 citation
Ayahuasca is an Amazonian tea made from Banisteriopsis caapi, which contains beta-carboline alkaloids (harmine, harmaline, tetrahydroharmine) that inhibit monoamine oxidase, and often Psychotria viridis leaves rich in DMT, a psychoactive 5-HT2A agonist. A new liquid chromatography-tandem mass spectrometry method was developed to quantify the major alkaloids and their metabolites in ayahuasca, human blood, and urine. The main components in the tea were tetrahydroharmine and harmine, followed by DMT and harmaline. DMT's major metabolite was DMT-N-oxide, found in blood and urine but not in the tea. Less than 1% of the DMT dose appeared in urine or blood, despite MAO inhibition. Tetrahydroharmine was the main harmala alkaloid excreted. The method is suitable for human, ethnobotanical, and forensic studies.