Mephedrone (4-methylmethcathinone) is a synthetic cathinone with psychostimulant properties which remains one of the most popular new psychoactive substances (NPS). It is frequently used orally and/or intranasally. To date, no studies have evaluated the acute effects and pharmacokinetics after self-administration of mephedrone orally (ingestion) and intranasally (insufflation) in naturalistic conditions. An observational study was conducted to assess and compare the acute pharmacological effects, as well as the oral fluid (saliva) concentrations of mephedrone self-administered orally and intranasally. Ten healthy experienced drug users (4 females and 6 males) self-administered a single dose of mephedrone, orally (n = 5, 100–200 mg; mean 150 mg) or intranasally (n = 5, 50–100 mg, mean 70 mg). Vital signs (blood pressure, heart rate, and cutaneous temperature) were measured at baseline (0), 1, 2, and 4 h after self-administration. Each participant completed subjective effects questionnaires: A set of Visual Analogue Scales (VAS), the 49-item Addiction Research Centre Inventory (ARCI), and Evaluation of the Subjective Effects of Substances with Abuse Potential (VESSPA-SSE) at baseline, 1, 2, and 4 h after self-administration. Oral fluid and urine were collected during 4 h. Both routes of mephedrone self-administration enhanced ratings of euphoria and well-being effects and increased cardiovascular effects in humans. Although it was at times assessed that the oral route produced greater and larger effects than the intranasal one, concentrations of mephedrone in oral fluid and also the total amount of mephedrone and metabolites in urine showed that concentrations of mephedrone are considerably higher when self-administered intranasally in comparison to orally. Controlled clinical trials are needed to confirm our observational results.

Considered the β-keto analogue of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy), 3,4-Methylenedioxymethcathinone (methylone) is a synthetic cathinone. Over the years, methylone has been used as a substitute for conventional psychostimulants, such as MDMA. To date, little is known about the human pharmacology of methylone; the only available information has been provided by surveys or published intoxication reports. In the present observational–naturalistic study, we evaluate the acute subjective and physiological effects of methylone after oral self-administration in comparison to MDMA in healthy poly-drug users. Fourteen participants (10 males, 4 females) selected their single oral doses of methylone from 100 to 300 mg (n = 8, mean dose 187.5 mg) or MDMA from 75 to 100 mg (n = 6, mean dose 87.5 mg) based on their experience. Study variables were assessed at 0, 1, 2, and 4 h (h) and included vital signs (non-invasive blood pressure, heart rate, cutaneous temperature) and subjective effects using visual analogue scales (VAS), the 49-item Addiction Research Centre Inventory (ARCI) short form, and the Evaluation of the Subjective Effects of Substances with Abuse Potential (VESSPA-SSE) questionnaire. Additionally, oral fluid concentrations of methylone and MDMA were determined. Acute pharmacological effects produced by methylone followed the prototypical psychostimulant and empathogenic profile associated with MDMA, although they were less intense. Methylone concentrations in oral fluid can be considered a useful biomarker to detect acute exposure in oral fluid. Oral fluid concentrations of MDMA and methylone peaked at 2 h and concentrations of MDMA were in the range of those previously described in controlled studies. Our results demonstrate that the potential abuse liability of methylone is similar to that of MDMA in recreational subjects.

New psychoactive tryptamines may be a public health risk since they intend to mimic the hallucinogenic effects of regulated psychoactive drugs. Few studies describe uses and clinical effects of unregulated new psychoactive tryptamines. This study aims (1) to explore the presence of tryptamines classified as NPS among the substances delivered for analysis to a harm-reduction organization; (2) to describe the substances found in the samples after analysis; and (3) to compare analytical results of regulated vs. non-regulated tryptamines. Samples delivered and analyzed by gas chromatography-mass spectrometry from 2006 to 2015 were included. A descriptive study of results was conducted. From 25,296 samples that were delivered, 436 were tryptamines; from these 232 (53.21%) were non-regulated. The most delivered non-regulated tryptamine was 4-AcO-DMT. A search of the PubMed database in July 2016 revealed that no studies in humans have ever been carried out with 4-AcO-DMT. Unregulated tryptamines likely contained one unadulterated substance (p ≤ 0.001). The number of samples submitted which contained tryptamines increased during the course of the study, with significant differences in client expectations vs. analysis results between the controlled and uncontrolled groups. There is a need for further research in order to prevent the potential health risks associated with their use.

Background: During the last few years, the continuous emergence of new psychoactive substances (NPS) has become an important public health challenge. The use of NPS has been rising in two different ways: buying and consuming NPS knowingly and the presence of NPS in traditional drugs as adulterants. The rise of NPS use is increasing the number of different substances in the market to an extent impossible to study with current scientific methodologies. This has caused a remarkable absence of necessary information about newer drug effects on people who use drugs, mental health professionals, and policy makers. Current scientific methodologies have failed to provide enough data in the timeframe when critical decisions must be made, being not only too slow but also too square. Last but not least, they dramatically lack the high resolution of phenomenological details. Objective: This study aims to characterize a population of e-psychonauts and the subjective effects of the NPS they used during the study period using a new, internet-based, fast, and inexpensive methodology. This will allow bridging an evidence gap between online surveys, which do not provide substance confirmation, and clinical trials, which are too slow and expensive to keep up with the new substances appearing every week. Methods: To cover this purpose, we designed a highly personalized, observational longitudinal study methodology. Participants will be recruited from online communities of people who use NPS, and they will be followed online by means of a continuous objective and qualitative evaluation lasting for at least 1 year. In addition, participants will send samples of the substances they intend to use during that period, so they can be analyzed and matched with the effects they report on the questionnaires. Results: The research protocol was approved by the Institutional Review Board of the Hospital del Mar Research Institute on December 11, 2018. Data collection started in August 2019 and was still ongoing when the protocol was submitted (September 2020). The first data collection period of the study ended in October 2020. Data analysis began in November 2020, and it is still ongoing. The authors expect to submit the first results for publication by the end of 2021. A preliminary analysis was conducted when the manuscript was submitted and was reviewed after it was accepted in February 2021. Conclusions: It is possible to conduct an institutional review board–approved study using this new methodology and collect the expected data. However, the meaning and usefulness of these data are still unknown. International Registered Report Identifier (IRRID): DERR1-10.2196/24433