Matthews, Douglas B.

Background: Preliminary evidence examining ibogaine in neuropsychiatric and substance use disorders is accumulating. As patient interest and off-label use grow, clinicians require an understanding of emerging dosing strategies, investigational protocols, and reported adverse effects to appropriately counsel patients and contextualize potential risks and benefits. Methods: Databases were searched for human studies of ibogaine, noribogaine, or 5-MeO-DMT with relevant clinical outcomes, prioritizing randomized controlled trials (RCTs), microdosing paradigms, and sequential protocols. Results: Only three RCTs were identified. First, a double-blind pilot study in 20 cocaine-dependent adults found that a single 1800 mg dose of ibogaine was associated with reduced craving versus placebo over follow-up of up to 24 weeks. Second, an ascending-dose trial in 36 healthy volunteers showed that noribogaine doses of 3–60 mg were safe and well-tolerated, without opioid-agonist effects. Third, a randomized crossover trial in 27 opioid-dependent patients receiving noribogaine 60–180 mg demonstrated dose-dependent heart rate-corrected QT interval (QTc) prolongation with non-significant reductions in withdrawal symptoms. Thus, two RCTs enrolled substance-dependent populations, while one focused on safety and pharmacokinetics in healthy volunteers. Microdosing and escalating sequential protocols remain experimental, lack standardized definitions, and are supported only by preliminary observational data. Adverse effects include neurologic, psychiatric, and cardiac events, including QTc prolongation; fatalities have occurred in the presence of medical and substance use comorbidities. Conclusions: The available evidence is confined to case reports, observational analyses, and small early-phase or proof-of-concept studies. Given ibogaine’s cardiotoxicity and narrow therapeutic margin, clinical use cannot be recommended without confirmation from larger, well-controlled trials.

The use of ketamine for the management of neuropsychiatric conditions outside clinical settings has rapidly expanded, creating a critical need to understand diverse individual experiences. We conducted a qualitative content analysis of posts from the r/TherapeuticKetamine subreddit. From 3302 threads, the 500 highest-engagement threads (12,852 comments) were analyzed by independent coders across six domains: perceived positive effects, adverse effects, reasons for use, route of administration, polydrug use, and dose amounts. Mood-related concerns were the primary reason for use (53%). Users reported positive effects, most often improvements in emotional well-being (65%). Adverse effects were predominantly psychological or mood-related (56%). A total of 70% of reported doses exceeded 149 mg, suggesting a trend toward higher dose use. Intravenous administration (40%) and sublingual troches (23%) were the most frequently reported routes. Concurrent use of prescribed psychotropics, cannabis, and psychedelics was also reported. This analysis identified substantial heterogeneity in individual-reported experiences. Frequent high-dose use, dose escalation, and polydrug exposure underscores the importance of clinical monitoring and attention to addiction potential and drug–drug interactions. The findings should be interpreted with caution, as follow-up and clinical verification were not possible; however, the data provide an unfiltered view of individual experiences in relation to ketamine use outside the clinical setting.

Abstract Introduction This study investigated if acute alcohol exposure produces sex differences in aged rats compared to adult and adolescent rats on ataxia and nonspatial cognition. Materials and Methods Sex- and age-related differences were assessed by using aged, young adult, and adolescent Sprague–Dawley rats. For acute alcohol exposure, animals were administered either 1 or 2 g/kg alcohol via intraperitoneal injection before testing. To examine the effects of acute alcohol exposure on balance and motor control and nonspatial learning, animals underwent behavioral testing in the aerial righting reflex (ARR) and Morris water maze (MWM) tests. Blood alcohol levels were determined 60 min following administration of either 1.0 or 2.0 g/kg alcohol. Results Sex differences were found in the ARR, as aged females were significantly less sensitive to the effect of acute alcohol exposure compared to aged males. Age was also found to significantly affect ARR performance, where aged animals performed worse than younger animals in response to acute alcohol. However, these sex- and age-related differences were not found in the nonspatial MWM test or in blood alcohol concentrations. Conclusions These results indicate that the sex- and age-dependent effects of acute alcohol exposure are task specific. In conclusion, these findings highlight the importance of studying the effects of acute alcohol on the aged population.