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Ketamine Effects on EEG during Therapy of Treatment-Resistant Generalized Anxiety and Social Anxiety

April 24, 2018 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By / , , , , ,

Abstract

BACKGROUND:
Ketamine is swiftly effective in a range of neurotic disorders that are resistant to conventional antidepressant and anxiolytic drugs. The neural basis for its therapeutic action is unknown. Here we report the effects of ketamine on the EEG of patients with treatment-resistant generalized anxiety and social anxiety disorders.
METHODS:
Twelve patients with refractory DSM-IV generalized anxiety disorder and/or social anxiety disorder provided EEG during 10 minutes of relaxation before and 2 hours after receiving double-blind drug administration. Three ascending ketamine dose levels (0.25, 0.5, and 1 mg/kg) and midazolam (0.01 mg/kg) were given at 1-week intervals to each patient, with the midazolam counterbalanced in dosing position across patients. Anxiety was assessed pre- and postdose with the Fear Questionnaire and HAM-A.
RESULTS:
Ketamine dose-dependently improved Fear Questionnaire but not HAM-A scores, decreased EEG power most at low (delta) frequency, and increased it most at high (gamma) frequency. Only the decrease in medium-low (theta) frequency at right frontal sites predicted the effect of ketamine on the Fear Questionnaire. Ketamine produced no improvement in Higuchi’s fractal dimension at any dose or systematic changes in frontal alpha asymmetry.
CONCLUSIONS:
Ketamine may achieve its effects on treatment-resistant generalized anxiety disorder and social anxiety disorder through related mechanisms to the common reduction by conventional anxiolytic drugs in right frontal theta. However, in the current study midazolam did not have such an effect, and it remains to be determined whether, unlike conventional anxiolytics, ketamine changes right frontal theta when it is effective in treatment-resistant depression.
Shadli, S. M., Kawe, T., Martin, D., McNaughton, N., Neehoff, S., & Glue, P. (2018). Ketamine Effects on EEG during Therapy of Treatment-Resistant Generalized Anxiety and Social Anxiety. International Journal of Neuropsychopharmacology. 10.1093/ijnp/pyy032
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Repeated intranasal ketamine for treatment-resistant depression – the way to go? Results from a pilot randomised controlled trial

March 15, 2018 / Depressive Disorders, Ketamine, Papers, Psychology, Publications / By / , , , , , ,

Abstract

BACKGROUND:
Ketamine research in depression has mostly used intravenous, weight-based approaches, which are difficult to translate clinically. Intranasal (IN) ketamine is a promising alternative but no controlled data has been published on the feasibility, safety and potential efficacy of repeated IN ketamine treatments.
METHODS:
This randomised, double-blind, placebo-controlled pilot study compared a 4-week course of eight treatments of 100 mg ketamine or 4.5 mg midazolam. Each treatment was given as 10 separate IN sprays, self-administered 5 min apart. The study was stopped early due to poor tolerability after five treatment-resistant depressed participants were included. Feasibility, safety (acute and cumulative), cognitive and efficacy outcomes were assessed. Plasma ketamine and norketamine concentrations were assayed after the first treatment.
RESULTS:
Significant acute cardiovascular, psychotomimetic and neurological side effects occurred at doses < 100 mg ketamine. No participants were able to self-administer all 10 ketamine sprays due to incoordination; treatment time occasionally had to be extended (>45 min) due to acute side effects. No hepatic, cognitive or urinary changes were observed after the treatment course in either group. There was an approximately two-fold variation in ketamine and norketamine plasma concentrations between ketamine participants. At course end, one participant had remitted in each of the ketamine and midazolam groups.
CONCLUSIONS:
IN ketamine, with the drug formulation and delivery device used, was not a useful treatment approach in this study. Absorption was variable between individuals and acute tolerability was poor, requiring prolonged treatment administration time in some individuals. The drug formulation, the delivery device, the insufflation technique and individual patient factors play an important role in tolerability and efficacy when using IN ketamine for TRD.
Gálvez, V., Li, A., Huggins, C., Glue, P., Martin, D., Somogyi, A. A., … & Loo, C. K. (2018). Repeated intranasal ketamine for treatment-resistant depression–the way to go? Results from a pilot randomised controlled trial. Journal of Psychopharmacology, 32(4), 397-407. 10.1177/0269881118760660
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Ketamine’s dose-related effects on anxiety symptoms in patients with treatment refractory anxiety disorders

April 26, 2017 / Anxiety Disorders / PTSD, Depressive Disorders, Ketamine, Papers, Psychology / By / , , , , ,

Abstract

The N-methyl-D-aspartate receptor antagonist ketamine has rapid onset activity in treatment-resistant depression, post-traumatic stress disorder and obsessive compulsive disorder. Due to similarities in brain network activity in depression and anxiety disorders, we hypothesized that ketamine might also be active in other refractory anxiety disorders. We evaluated the efficacy and safety of ketamine in 12 patients with refractory generalized anxiety disorder and/or social anxiety disorder who were not currently depressed, using an ascending single dose study design (0.25, 0.5, 1 mg/kg administered subcutaneously) at weekly intervals. Within 1 h of dosing, patients reported reduced anxiety, which persisted for up to seven days. A dose-response profile was noted for anxiolytic effects, dissociative side effects, and changes in blood pressure and heart rate, with minor changes at 0.25 mg/kg, and progressively greater and more durable changes at the higher doses. Ten of 12 patients were treatment responders at 0.5–1 mg/kg. Ketamine was safe and well tolerated in this population. Ketamine may be a potential therapeutic alternative for patients with refractory generalized anxiety disorder/social anxiety disorder. Along with its demonstrated effectiveness in patients with treatment-resistant depression, obsessive compulsive disorder and post-traumatic stress disorder, these data raise the intriguing possibility that ketamine may have broad efficacy in disorders characterized by negative emotional states, and that these disorders may share a common precipitating neurobiology.
Glue, P., Medlicott, N. J., Harland, S., Neehoff, S., Anderson-Fahey, B., Le Nedelec, M., … & McNaughton, N. (2017). Ketamine’s dose-related effects on anxiety symptoms in patients with treatment refractory anxiety disorders. Journal of Psychopharmacology, 0269881117705089.
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Effects of low dose ibogaine on subjective mood state and psychological performance

May 11, 2016 / Iboga / Ibogaine, Papers, Psychology, Publications / By / , , , , , ,

Abstract

Ethnopharmacological relevance: Root bark from Tabernanthe iboga has been used traditionally in West Africa as a psychoactive substance in religious rituals. In smaller doses it is reported anecdotally to have stimulant properties.

Aim of the study: To evaluate the influence of a single 20 mg ibogaine dose on psychological variables reflecting subjective mood state and a range of cognitive functions.

Materials and methods: 21 healthy male volunteers received single 20 mg doses of ibogaine after 6 days pretreatment with double-blind paroxetine or placebo. We compared responses to a battery of psychometric tests and subjective mood ratings performed before and 2 h after ibogaine dosing, and assessed relationships between changes in test scores and concentrations of active moiety (the sum of molar noribogaine and ibogaine concentrations). Psychological tests were chosen based on responsiveness to opioid and serotonergic ligands.

Results: Ibogaine had minimal influence on psychological tests and mood ratings. The ability to selectively ignore distracting spatial information showed some evidence of modulation; however because this effect was limited to the less challenging condition calls into question the reliability of this result.

Conclusion: We were unable to identify stimulant effects after single 20 mg doses of ibogaine. Future research is needed to confirm whether active moiety concentrations impact selective attention abilities while leaving other cognitive functions and mood state unaffected.

Forsyth, B., Machado, L., Jowett, T., Jakobi, H., Garbe, K., Winter, H., & Glue, P. (2016). Effects of low dose ibogaine on subjective mood state and psychological performance. Journal of Ethnopharmacology. http://dx.doi.org/10.1016/j.jep.2016.05.022

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Ascending single-dose, double-blind, placebo-controlled safety study of noribogaine in opioid-dependent patients

February 10, 2016 / Iboga / Ibogaine, Papers, Publications, Substance Use Disorder / By / , , , , , ,

Abstract

Ibogaine is a psychoactive substance that may reduce opioid withdrawal symptoms. This was the first clinical trial of noribogaine, ibogaine’s active metabolite, in patients established on methadone opioid substitution therapy (OST). In this randomized, double-blind, placebo-controlled, single ascending dose study, we evaluated the safety, tolerability, and pharmacokinetics of noribogaine in 27 patients seeking to discontinue methadone OST, who had been switched to morphine during the previous week. Noribogaine doses were 60, 120 or 180mg (n = 6/dose level) or matching placebo (n = 3/dose level). Noribogaine was well tolerated. The most frequent treatment-emergent adverse events were non-euphoric changes in light perception at ∼1h post dose, headache and nausea. Noribogaine had dose-linear increases for AUC and Cmax, and was slowly eliminated (mean t1/2 range 24–30h). There was a concentration-dependent increase in QTcI (0.17msec/ng/mL) with largest observed mean effect of ∼16msec, 28msec, and 42msec in the 60mg, 120mg, and 180mg groups, respectively. Noribogaine showed a non-statistically significant trend to decrease total scores in opioid withdrawal ratings, most notably at the 120mg dose, however the study design may have confounded evaluations of time to resumption of OST. Future exposure-controlled multiple-dose noribogaine studies are planned that will address these safety and design issues.

Glue, P., Cape, G., Tunnicliff, D., Lockhart, M., Lam, F., Hung, N., … & Howes, J. (2016). Ascending single‐dose, double‐blind, placebo‐controlled safety study of noribogaine in opioid‐dependent patients. Clinical Pharmacology in Drug Development. http://dx.doi.org/10.1002/cpdd.254
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Influence of CYP2D6 activity on the pharmacokinetics and pharmacodynamics of a single 20 mg dose of ibogaine in healthy volunteers

February 4, 2015 / Iboga / Ibogaine, Papers, Publications / By / , , , , , ,

Abstract

Conversion of ibogaine to its active metabolite noribogaine appears to be mediated primarily by CYP2D6. We compared 168 h pharmacokinetic profiles of both analytes after a single oral 20 mg dose of ibogaine in 21 healthy subjects who had been pretreated for 6 days with placebo or the CYP2D6 inhibitor paroxetine. In placebo-pretreated subjects, ibogaine was rapidly converted to noribogaine. Median peak noribogaine concentrations occurred at 4 h. Compared with placebo-pretreated subjects, paroxetine-pretreated subjects had rapid (Tmax = 1.5 h) and substantial absorption of ibogaine, with detectable levels out to 72 h, and an elimination half-life of 10.2 h. In this group, ibogaine was also rapidly converted to noribogaine with a median Tmax of 3 h. Extent of noribogaine exposure was similar in both groups. CYP2D6 phenotype was robustly correlated with ibogaine AUC0-t (r = 0.82) and Cmax (r = 0.77). Active moiety (ibogaine plus noribogaine) exposure was ∼2-fold higher in paroxetine-pretreated subjects. Single 20 mg ibogaine doses were safe and well tolerated in all subjects. The doubling of exposure to active moiety in subjects with reduced CYP2D6 activity suggests it may be prudent to genotype patients awaiting ibogaine treatment, and to at least halve the intended dose of ibogaine in CYP2D6 poor metabolizers.

Glue, P., Winter, H., Garbe, K., Jakobi, H., Lyudin, A., Lenagh‐Glue, Z., & Hung, C. T. (2015). Influence of CYP2D6 activity on the pharmacokinetics and pharmacodynamics of a single 20 mg dose of ibogaine in healthy volunteers. The Journal of Clinical Pharmacology. https://dx.doi.org/10.1002/jcph.471
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Ascending-dose study of noribogaine in healthy volunteers: Pharmacokinetics, pharmacodynamics, safety, and tolerability

December 22, 2014 / Iboga / Ibogaine, Papers, Publications / By / , , , , ,

Abstract

Noribogaine is the active metabolite of the naturally occurring psychoactive substance ibogaine, and may help suppress withdrawal symptoms in opioid-dependent subjects. The objectives of this Phase I study were to assess the safety, tolerability, pharmacokinetic, and pharmacodynamic profiles of noribogaine. In this ascending single-dose, placebo-controlled, randomized, double-blind, parallel-group study in 36 healthy drug-free male volunteers, 4 cohorts (n = 9) received oral doses of 3, 10, 30, or 60 mg or matching placebo, with intensive safety and pharmacokinetic assessments out to 216 hours, along with pharmacodynamic assessments sensitive to the effects of mu-opioid agonists. Noribogaine was rapidly absorbed, with peak concentrations occurring 2–3 hours after oral dosing, and showed dose-linear increases of area under the concentration–time curve (AUC) and Cmax between 3 and 60 mg. The drug was slowly eliminated, with mean half-life estimates of 28–49 hours across dose groups. Apparent volume of distribution was high (mean 1417–3086 L across dose groups). No safety or tolerability issues were identified in any cohort. No mu-opioid agonist pharmacodynamic effects were noted in pupillometry or cold-pressor testing. Single oral doses of noribogaine 3–60 mg were safe and well tolerated in healthy volunteers.

Glue, P., Lockhart, M., Lam, F., Hung, N., Hung, C. T., & Friedhoff, L. (2014). Ascending‐dose study of noribogaine in healthy volunteers: Pharmacokinetics, pharmacodynamics, safety, and tolerability. The Journal of Clinical Pharmacology. https://dx.doi.org/10.1002/jcph.404

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