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Important new research project about ayahuasca in the USA

Title: ‘Safety and neurochemical effects of ayahuasca in healthy adults: Phase I and II studies

Principle investigator: Leanna Standish, ND, PhD at Bastyr University in Seattle (see a text of her here).

Summary presented in an National Institue of Health (NIH) grant proposal

Background: Ayahuasca is an ancient Amazonian psychoactive botanical extract used as a tea for religious and medical purposes in S. America, N. America and Europe, with increasing use by the U.S. public. Little is understood about its potential dangers or its potential therapeutic activity in psychiatric and neurological disorders as a novel monoamine neuromodulatory botanical drug. Our goal is to evaluate the safety of this potential drug of abuse and potential therapeutic applications of ayahuasca by studying its physiological and psychological effects, as well as its peripheral and central neurochemical effects at dosages that are typical for the religious use of this substance.

Methods: 66 healthy adults who are naïve to ayahuasca in Phase I and naive to all hallucinogenic drugs in Phase II, will be screened, consented and enrolled. Phase I (n=30) is a single-blind, placebo-controlled, dose-finding, dose-escalation pharmacokinetic and safety study. Both psychological and physiological safety will be evaluated. Phase II (n=36) is a double-blind, placebo controlled randomized study that will use a dose determined in Phase I to measure the psychological effects, peripheral serotonergic effects and the central effects on gamma-amino butyric acid (GABA), glutamate, N-acetyl aspartate and choline. We will 1) determine the minimally effective dose of ayahuasca and correlate with plasma levels of the known active constituents (dimethyltryptamine, harmine, harmaline, tetrahydroharmine), 2) describe quantitatively the dose-response pharmacokinetics of ayahuasca’s active constituents following oral administration, 3) quantitate monoamine oxidase (MAO) A and B inhibition in plasma from human subjects and to describe the dose-response pharmacokinetics of MAO inhibitor activity following oral administration of ayahuasca, and 4) conduct a Phase II study of the neurochemical effects of repeated exposure to ayahuasca. We will measure 1) psychological changes using a battery of standardized psychological tests, 2) serotonergic changes in platelet 5-HT transporter binding using the 3H-citalopram binding assay, and 3) changes in brain N-acetyl aspartate, GABA, glutamate and choline levels using proton magnetic resonance spectroscopic imaging with spectral editing.

Significance: Ayahuasca is used by thousands of people throughout the U.S. yet its safety across doses has not been studied. The alkaloids contained in ayahuasca represent a novel potent long-acting serotonin agonist with potential in the treatment of drug and alcohol abuse, depression, anxiety and obsessive compulsive disorder. Phase I and II studies are needed to develop a standardized and safe botanical drug that has applications highly relevant to NIH’s mission, especially the mission of NIDA to develop new and more effective therapies to treat drug dependency, NIAAA’s mission to treat alcoholism, the mission of NIMH to develop new therapies for mood disorders and the mission of NCCAM to evaluate promising ethnomedicines.

Filed under: Science


Beatriz Caiuby Labate or Bia Labate was born in São Paulo in 1971. She earned a bachelor’s degree in social science from the State University of Campinas (UNICAMP) in 1996. In 2000 she obtained a master’s degree in social anthropology from the same university, receiving the Prize for Best Master’s Thesis from the National Association for Graduate Studies in Social Science (ANPOCS). Her doctoral research in social anthropology at UNICAMP focuses on the internationalization of Peruvian ayahuasca “vegetalismo.” She is co-editor of the books O uso ritual da ayahuasca (Mercado de Letras 2002) and O uso ritual das plantas de poder (Mercado de Letras, 2005) and author of the book A reinvenção do uso da ayahuasca nos centros urbanos (Mercado de Letras, 2004). She is a researcher with the Nucleus for Interdisciplinary Studies of Psychoactives (NEIP). In February 2005 she founded Alto das Estrelas, a private institute which promotes political activism, anthropological research and public events, in addition to researching the cultivation and preparation of vegetal species.


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