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Safety

Evaluating the abuse potential of psychedelic drugs for medical use in humans

Abstract

Psychedelics comprise drugs come from various pharmacological classes including 5-HT2A agonists, indirect 5-HT agonists, e.g. MDMA, NMDA antagonists and κ-opioid receptor agonists. There is resurgence in developing psychedelics to treat psychiatric disorders with high unmet clinical need. Many, but not all, psychedelics are schedule 1 controlled drugs (CDs), i.e. no approved medical use. For existing psychedelics in development, regulatory approval will require a move from schedule 1 to a CD schedule for drugs with medical use, i.e. schedules 2-5. Although abuse of the psychedelics is well documented, a systematic preclinical and clinical evaluation of the risks they pose in a medical-use setting does not exist. We describe the non-clinical tests required for a regulatory evaluation of abuse/dependence risks, i.e. drug-discrimination, intravenous self-administration and physical dependence liability. A synopsis of the existing data for the various types of psychedelics is provided and we describe our findings with psychedelic drugs in these models. FDA recently issued its guidance on abuse/dependence evaluation of drug-candidates [59]. We critically review the guidance, discuss the impact this document will have on non-clinical abuse/dependence testing, and offer advice on how non-clinical abuse/dependence experiments can be designed to meet not only the expectations of FDA, but also other regulatory agencies. Finally, we offer views on how these non-clinical tests can be refined to provide more meaningful information to aid the assessment of the risks posed by CNS drug-candidates for abuse and physical dependence.
Heal, D. J., Gosden, J., & Smith, S. L. (2018). Evaluating the abuse potential of psychedelic drugs for medical use in humans. Neuropharmacology. 10.1016/j.neuropharm.2018.01.049
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Is LSD toxic?

Abstract

LSD (lysergic acid diethylamide) was discovered almost 75 years ago, and has been the object of episodic controversy since then. While initially explored as an adjunctive psychiatric treatment, its recreational use by the general public has persisted and on occasion has been associated with adverse outcomes, particularly when the drug is taken under suboptimal conditions. LSD’s potential to cause psychological disturbance (bad trips) has been long understood, and has rarely been associated with accidental deaths and suicide. From a physiological perspective, however, LSD is known to be non-toxic and medically safe when taken at standard dosages (50–200 μg). The scientific literature, along with recent media reports, have unfortunately implicated “LSD toxicity” in five cases of sudden death. On close examination, however, two of these fatalities were associated with ingestion of massive overdoses, two were evidently in individuals with psychological agitation after taking standard doses of LSD who were then placed in maximal physical restraint positions (hogtied) by police, following which they suffered fatal cardiovascularcollapse, and one case of extreme hyperthermia leading to death that was likely caused by a drug substituted for LSD with strong effects on central nervous system temperature regulation (e.g. 25i-NBOMe). Given the renewed interest in the therapeutic potential of LSD and other psychedelic drugs, it is important that an accurate understanding be established of the true causes of such fatalities that had been erroneously attributed to LSD toxicity, including massive overdoses, excessive physical restraints, and psychoactive drugs other than LSD.

Nichols, D. E., & Grob, C. S. (2018). Is LSD toxic?. Forensic science international284, 141-145. 10.1016/j.forsciint.2018.01.006
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Psychedelics and the essential importance of context

Abstract

Psychedelic drugs are making waves as modern trials support their therapeutic potential and various media continue to pique public interest. In this opinion piece, we draw attention to a long-recognised component of the psychedelic treatment model, namely ‘set’ and ‘setting’ – subsumed here under the umbrella term ‘context’. We highlight: (a) the pharmacological mechanisms of classic psychedelics (5-HT2A receptor agonism and associated plasticity) that we believe render their effects exceptionally sensitive to context, (b) a study design for testing assumptions regarding positive interactions between psychedelics and context, and (c) new findings from our group regarding contextual determinants of the quality of a psychedelic experience and how acute experience predicts subsequent long-term mental health outcomes. We hope that this article can: (a) inform on good practice in psychedelic research, (b) provide a roadmap for optimising treatment models, and (c) help tackle unhelpful stigma still surrounding these compounds, while developing an evidence base for long-held assumptions about the critical importance of context in relation to psychedelic use that can help minimise harms and maximise potential benefits.
Carhart-Harris, R. L., Roseman, L., Haijen, E., Erritzoe, D., Branchi, I., & Kaelen, M. (2018). Psychedelics and the essential importance of context. Journal of Psychopharmacology, 0269881118754710.
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Key interindividual determinants in MDMA pharmacodynamics.

Abstract

MDMA, 3,4-methylenedioxymethamphetamine, is a synthetic phenethylamine derivative with structural and pharmacological similarities to both amphetamines and mescaline. MDMA produces characteristic amphetamine-like actions (euphoria, well-being), increases empathy, and induces pro-social effects that seem to motivate its recreational consumption and provide a basis for its potential therapeutic use. Areas covered: The aim of this review is to present the main interindividual determinants in MDMA pharmacodynamics. The principal sources of pharmacodynamic variability are reviewed, with special emphasis on sex-gender, race-ethnicity, genetic differences, interactions, and MDMA acute toxicity, as well as possible therapeutic use. Expert opinion: Acute MDMA effects are more pronounced in women than they are in men. Very limited data on the relationship between race-ethnicity and MDMA effects are available. MDMA metabolism includes some polymorphic enzymes that can slightly modify plasma concentrations and effects. Although a considerable number of studies exist about the acute effects of MDMA, the small number of subjects in each trial limits evaluation of the different interindividual factors and does not permit a clear conclusion about their influence. These issues should be considered when studying possible MDMA therapeutic use.
Papaseit, E., Torrens, M., Pérez-Mañá, C., Muga, R., & Farré, M. (2018). Key interindividual determinants in MDMA pharmacodynamics. Expert opinion on drug metabolism & toxicology, (just-accepted). 10.1080/17425255.2018.1424832
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A regulatory perspective on the evaluation of hallucinogen drugs for human use

Abstract

In recent years, there is renewed interest in the study of various hallucinogens for their potential therapeutic effects. In the United States of America (USA), the abuse potential assessment of a drug is carried out as part of the general safety and efficacy evaluation of a drug. Additionally, the abuse potential assessment is taken under consideration in determining if a drug needs to be subject to controls to minimize the abuse of the drug once on the market. This assessment is conducted for all new drugs with central nervous system (CNS) activity, that are chemically or pharmacologically similar to other drugs with known abuse potential, or drugs that produce psychoactive effects predictive of abuse, such as euphoria and hallucinations. This paper describes the regulatory framework for evaluating the abuse potential of new drugs, with emphasis on hallucinogens. The paper discusses the role of the United States Food and Drug Administration (FDA) in the evaluation of the abuse potential of drugs and its role in drug control, and provides an overview of the controlled status of hallucinogens and the requirements to conduct research with Schedule I substances in the USA.

Calderon, S. N., Hunt, J., & Klein, M. (2017). A regulatory perspective on the evaluation of hallucinogen drugs for human use. Neuropharmacology. 10.1016/j.neuropharm.2017.11.028
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Regulation of human research with LSD in the United States (1949-1987)

Abstract

Human research with hallucinogens such as lysergic acid diethylamide (LSD) has been ongoing in the USA since 1949. During the 1960s, LSD was investigated for a variety of psychiatric indications, including the following: as an aid in treatment of schizophrenia; as a means of creating a “model psychosis”; as a direct antidepressant; and as an adjunct to psychotherapy. Studies with all drugs, including LSD, have always been conducted under federal regulatory controls, including the 1938 Food Drug and Cosmetic Act (FDCA; which ensured the safety of drugs) and the 1962 Kefauver-Harris Amendments to the FDCA (which described appropriate scientific methodology and ensured drug efficacy). This paper details how the 1962 Amendments introduced numerous safety and efficacy requirements that must be in satisfied during clinical drug research-and how human studies conducted with LSD in the 1960s struggled with their fulfillment. Information is provided from Senate hearings, case law, and interviews with key investigators. Examples are also drawn from scientific papers and symposia published during and since that period, with a focus on information from clinical studies conducted with LSD by psychiatrist Albert Kurland at the Spring Grove State Hospital, near Baltimore, MD. While Kurland largely conformed with these new regulations, other investigators often fell short of complying with scientific standards and federal requirements. Thus, the human hallucinogen studies of the 1960s are best understood as providing pilot data on safety and efficacy, as well as testable hypotheses for current hallucinogen studies conducted under modern scientific and regulatory standards.
Bonson, K. R. (2017). Regulation of human research with LSD in the United States (1949-1987). Psychopharmacology, 1-14. 10.1007/s00213-017-4777-4
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Psychedelic Drugs in Biomedicine

Abstract

Psychedelic drugs, such as lysergic acid diethylamide (LSD), mescaline, and psilocybin, exert profound effects on brain and behavior. After decades of difficulties in studying these compounds, psychedelics are again being tested as potential treatments for intractable biomedical disorders. Preclinical research of psychedelics complements human neuroimaging studies and pilot clinical trials, suggesting these compounds as promising treatments for addiction, depression, anxiety, and other conditions. However, many questions regarding the mechanisms of action, safety, and efficacy of psychedelics remain. Here, we summarize recent preclinical and clinical data in this field, discuss their pharmacological mechanisms of action, and outline critical areas for future studies of psychedelic drugs, with the goal of maximizing the potential benefits of translational psychedelic biomedicine to patients.
Kyzar, E. J., Nichols, C. D., Gainetdinov, R. R., Nichols, D. E., & Kalueff, A. V. (2017). Psychedelic Drugs in Biomedicine. Trends in Pharmacological Sciences. 10.1016/j.tips.2017.08.003
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First Time View on Human Metabolome Changes after a Single Intake of 3,4-Methylenedioxymethamphetamine in Healthy Placebo-Controlled Subjects

Abstract

3,4-Methylenedioxymethamphetamine (MDMA; “ecstasy”) is widely consumed recreationally. Little is known about its effects on the human metabolome. Mapping biochemical changes after drug exposure can complement traditional approaches by revealing potential biomarkers of organ toxicity or discovering new metabolomic features in a time- and dose-dependent manner. We aimed to analyze for the first time plasma samples from a randomized, double-blind, placebo-controlled crossover study in healthy adults to explore changes in endogenous plasma metabolites following a single intake of MDMA. Plasma samples from 15 subjects taken at four different time points were analyzed with the commercially available AbsoluteIDQ kit (Biocrates). Time series analysis revealed a total of nine metabolites, which showed a significant concentration change after MDMA administration compared with placebo. Paired t tests of the single time points showed statistically significant concentration changes mainly of glycerophospholipids and the metabolic ratio of methionine-sulfoxide over methionine. Changes of this metabolic ratio may be indicative for changes in systemic oxidative stress levels, and the increased amount of glycerophospholipids could be interpreted as an upregulation of energy production. Baseline samples within the experimental study design were crucial for evaluation of metabolomics data as interday individuality within subjects was high otherwise resulting in overestimations of the findings.
Boxler, M. I., Liechti, M. E., Schmid, Y., Kraemer, T., & Steuer, A. E. (2017). First Time View on Human Metabolome Changes after a Single Intake of 3, 4-Methylenedioxymethamphetamine in Healthy Placebo-Controlled Subjects. Journal of proteome research16(9), 3310-3320. 10.1021/acs.jproteome.7b00294
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MDMA and brain activity during neurocognitive performance: An overview of neuroimaging studies with abstinent ‘Ecstasy’ users

Abstract

MDMA/Ecstasy has had a resurgence in popularity, with recent supplies comprising higher strength MDMA, potentially leading to increased drug-related harm. Neurocognitive problems have been widely reported in ecstasy users, equally some studies report null findings, and it remains unclear which factors underlie the development of neurocognitive impairments. This review covers the empirical research into brain activity during neurocognitive performance, using fMRI, fNIRS, and EEG. Our main conclusion is that chronic repeated use of recreational ecstasy can result in haemodynamic and electrophysiological changes that reflect recruitment of additional resources to perform cognitive tasks.

Findings are consistent with serotonergic system changes, although whether this reflects neurotoxicity or neuroadaptation, cannot be answered from these data. There is a degree of heterogeneity in the methodologies and findings, limiting the strengths of current conclusions. Future research with functional neuroimaging paired with molecular imaging, genetics or pharmacological challenges of the serotonin system may help to decipher the link between serotonergic and cognitive changes in ecstasy users.

Roberts, C. A., Quednow, B. B., Montgomery, C., & Parrott, A. C. (2017). MDMA and brain activity during neurocognitive performance: An overview of neuroimaging studies with abstinent ‘Ecstasy’users. Neuroscience & Biobehavioral Reviews. 10.1016/j.neubiorev.2017.07.015
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Side-effects associated with ketamine use in depression: a systematic review

Abstract

This is the first systematic review of the safety of ketamine in the treatment of depression after single and repeated doses. We searched MEDLINE, PubMed, PsycINFO, and Cochrane Databases and identified 288 articles, 60 of which met the inclusion criteria. After acute dosing, psychiatric, psychotomimetic, cardiovascular, neurological, and other side-effects were more frequently reported after ketamine treatment than after placebo in patients with depression. Our findings suggest a selective reporting bias with limited assessment of long-term use and safety and after repeated dosing, despite these being reported in other patient groups exposed to ketamine (eg, those with chronic pain) and in recreational users. We recommend large-scale clinical trials that include multiple doses of ketamine and long-term follow up to assess the safety of long-term regular use.
Short, B., Fong, J., Galvez, V., Shelker, W., & Loo, C. K. (2017). Side-effects associated with ketamine use in depression: a systematic review. The Lancet Psychiatry. 10.1016/S2215-0366(17)30272-9
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