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P. Hutson

Exposure-Response Analysis to Assess the Concentration-QTc Relationship of Psilocybin/Psilocin

April 6, 2020 / Medicine, Mushrooms / Psilocybin, Other subjects, Papers, Psychotherapy, Publications, Safety, Toxicology / By / , ,

Abstract

Psilocybin is being developed for treating major depressive disorder. Psilocybin is readily dephosphorylated to psilocin upon absorption. The potential for psilocin proarrhythmic effect was assessed using a concentration-QTc interval (C-QTc) analysis from an open-label single ascending dose study of psilocybin. Psilocybin doses ranged from 0.3 to 0.6 mg/kg. This trial showed a significant but shallow C-QTc relationship. At the clinical dose of 25 mg, the mean psilocin maximum concentration is 18.7 ng/mL, and the associated mean (upper 90% confidence interval of mean) QTcF change is 2.1 (6.6) milliseconds. Given the short half-life of psilocin of about 4 hours, there would be no accumulation after monthly oral doses used in clinical trials. The upper limit of the 90% confidence interval of the model-predicted mean ΔQTcF crossed 10 milliseconds at a psilocin concentration of 31.1 ng/mL. At a supraclinical psilocin maximum concentration of about 60 ng/mL, ΔQTcF remains low, with a mean (upper limit of the 90% confidence interval) of 9.1 (17.9) milliseconds. This analysis enabled the characterization of the C-QTc relationship and prediction of QTc prolongation at the expected clinical and possible higher psilocybin doses.

Dahmane, E., Hutson, P. R., & Gobburu, J. V. (2020). Exposure‐Response Analysis to Assess the Concentration‐QTc Relationship of Psilocybin/Psilocin. Clinical Pharmacology in Drug Development.; 10.1002/cpdd.796

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The experimental effects of psilocybin on symptoms of anxiety and depression: A meta-analysis.

January 2, 2020 / Anxiety disorders / PTSD, Depression, Mushrooms / Psilocybin, Papers, Psychiatry, Psychology, Psychopharmacology, Publications / By / , , , ,

Abstract

The current meta-analysis examined the effects of psilocybin in combination with behavioral interventions on anxiety and depression in samples with elevated symptoms. Across four studies (one uncontrolled; three randomized, placebo-controlled; N = 117), within-group pre-post and pre-follow-up effects on anxiety and depression were large (Hedges’ gs=1.16 to 1.47) and statistically significant. Across three placebo-controlled studies, pre-post placebo-controlled effects were also large (gs = 0.82 to 0.83) and statistically significant. No serious adverse events were reported. Limitations include the small number of studies and risk for bias within studies. Results tentatively support future research on psilocybin for the treatment of anxiety and depression.

Goldberg, S. B., Pace, B. T., Nicholas, C. R., Raison, C. L., & Hutson, P. R. (2020). The experimental effects of psilocybin on symptoms of anxiety and depression: A meta-analysis. Psychiatry Research, 112749., https://doi.org/10.1016/j.psychres.2020.112749
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High dose psilocybin is associated with positive subjective effects in healthy volunteers

June 27, 2018 / Mushrooms / Psilocybin, Mystical experiences, Papers, Psychiatry, Psychology, Publications / By / , , , , , ,

Abstract

AIM:
The aim of the current study was to investigate the relationship between escalating higher doses of psilocybin and the potential psilocybin occasioned positive subjective effects.
METHODS:
Healthy participants ( n=12) were given three escalating doses of oral psilocybin (0.3 mg/kg; 0.45 mg/kg; 0.6 mg/kg) or (18.8-36.6 mg; 27.1-54.0 mg; 36.3-59.2 mg) a minimum of four weeks apart in a supervised setting. Blood and urine samples, vital signs, and electrocardiograms were obtained. Subjective effects were assessed using the Mystical Experience Questionnaire and Persisting Effects Questionnaire.
RESULTS:
There was a significant linear dose-related response in Mystical Experience Questionnaire total score and the transcendence of time and space subscale, but not in the rate of a complete mystical experience. There was also a significant difference between dose 3 compared to dose 1 on the transcendence of time and space subscale, while no dose-related differences were found for Mystical Experience Questionnaire total scores or rate of a mystical experience. Persisting Effects Questionnaire positive composite scores 30 days after completion of the last dose were significantly higher than negative composite scores. Persisting Effects Questionnaire results revealed a moderate increase in sense of well-being or life satisfaction on average that was associated with the maximum Mystical Experience Questionnaire total score. Pharmacokinetic measures were associated with dose but not with Mystical Experience Questionnaire total scores or rate of a mystical experience.
CONCLUSIONS:
High doses of psilocybin elicited subjective effects at least as strong as the lower doses and resulted in positive persisting subjective effects 30 days after, indicating that a complete mystical experience was not a prerequisite for positive outcomes.
Nicholas, C. R., Henriquez, K. M., Gassman, M. C., Cooper, K. M., Muller, D., Hetzel, S., … & Hutson, P. R. (2018). High dose psilocybin is associated with positive subjective effects in healthy volunteers. Journal of Psychopharmacology, 0269881118780713.
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Pharmacokinetics of Escalating Doses of Oral Psilocybin in Healthy Adults

March 28, 2017 / Mushrooms / Psilocybin, Papers, Psychology, Psychopharmacology, Publications, Safety, Toxicology / By / , , , , , ,

Abstract

INTRODUCTION: Psilocybin is a psychedelic tryptamine that has shown promise in recent clinical trials for the treatment of depression and substance use disorders. This open-label study of the pharmacokinetics of psilocybin was performed to describe the pharmacokinetics and safety profile of psilocybin in sequential, escalating oral doses of 0.3, 0.45, and 0.6 mg/kg in 12 healthy adults.

METHODS: Eligible healthy adults received 6-8 h of preparatory counseling in anticipation of the first dose of psilocybin. The escalating oral psilocybin doses were administered at approximately monthly intervals in a controlled setting and subjects were monitored for 24 h. Blood and urine samples were collected over 24 h and assayed by a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for psilocybin and psilocin, the active metabolite. The pharmacokinetics of psilocin were determined using both compartmental (NONMEM) and noncompartmental (WinNonlin) methods.

RESULTS: No psilocybin was found in plasma or urine, and renal clearance of intact psilocin accounted for less than 2% of the total clearance. The pharmacokinetics of psilocin were linear within the twofold range of doses, and the elimination half-life of psilocin was 3 h (standard deviation 1.1). An extended elimination phase in some subjects suggests hydrolysis of the psilocin glucuronide metabolite. Variation in psilocin clearance was not predicted by body weight, and no serious adverse events occurred in the subjects studied.

CONCLUSIONS: The small amount of psilocin renally excreted suggests that no dose reduction is needed for subjects with mild-moderate renal impairment. Simulation of fixed doses using the pharmacokinetic parameters suggest that an oral dose of 25 mg should approximate the drug exposure of a 0.3 mg/kg oral dose of psilocybin. Although doses of 0.6 mg/kg are in excess of likely therapeutic doses, no serious physical or psychological events occurred during or within 30 days of any dose.

Brown, R. T., Nicholas, C. R., Cozzi, N. V., Gassman, M. C., Cooper, K. M., Muller, D., … & Hutson, P. R. (2017). Pharmacokinetics of Escalating Doses of Oral Psilocybin in Healthy Adults. Clinical Pharmacokinetics, 1-12. 10.1007/s40262-017-0540-6
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30 April - Q&A with Rick Strassman

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