Pharmacology of ayahuasca administered in two repeated doses
Rafael G. Dos Santos, Eva Grasa, Marta Valle, María Rosa Ballester, José Carlos Bouso, Josep Nomdedéu, R. Homs, Manel J. Barbanoj, Jordi Riba
Psychopharmacology August 12, 2011 DOI: 10.1007/s00213-011-2434-x (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Double-blind, crossover, placebo-controlled clinical trial Peer reviewed |
|---|---|
| Sample size | 9 |
| Population | Experienced psychedelic drug users |
| Interventions | Ayahuasca Lactose placebo |
| Dose | 0.75 mg DMT/kg bodyweight |
| Duration | 4-hour interval between doses, 12-hour total measurement period |
| Topics | Ayahuasca |
| Keywords | Placebo Crossover study Pharmacology Sensitization Prolactin Agonist |
| Citations | 139 |
| Key findings | No clear tolerance or sensitization in psychological or most physiological variables, but a trend to lower cardiovascular activation and significant tolerance to growth hormone secretion after repeated ayahuasca doses. |
Abstract
RationaleAyahuasca is an Amazonian tea containing the natural psychedelic 5-HT(2A/2C/1A) agonist N,N-dimethyltryptamine (DMT). It is used in ceremonial contexts for its visionary properties. The human pharmacology of ayahuasca has been well characterized following its administration in single doses.ObjectivesTo evaluate the human pharmacology of ayahuasca in repeated doses and assess the potential occurrence of acute tolerance or sensitization.MethodsIn a double-blind, crossover, placebo-controlled clinical trial, nine experienced psychedelic drug users received PO the two following treatment combinations at least 1 week apart: (a) a lactose placebo and then, 4 h later, an ayahuasca dose; and (b) two ayahuasca doses 4 h apart. All ayahuasca doses were freeze-dried Amazonian-sourced tea encapsulated to a standardized 0.75 mg DMT/kg bodyweight. Subjective, neurophysiological, cardiovascular, autonomic, neuroendocrine, and cell immunity measures were obtained before and at regular time intervals until 12 h after first dose administration.ResultsDMT plasma concentrations, scores in subjective and neurophysiological variables, and serum prolactin and cortisol were significantly higher after two consecutive doses. When effects were standardized by plasma DMT concentrations, no differences were observed for subjective, neurophysiological, autonomic, or immunological effects. However, we observed a trend to reduced systolic blood pressure and heart rate, and a significant decrease for growth hormone (GH) after the second ayahuasca dose.ConclusionsWhereas there was no clear-cut tolerance or sensitization in the psychological sphere or most physiological variables, a trend to lower cardiovascular activation was observed, together with significant tolerance to GH secretion.