Pharmacokinetics of 'party pill' drug N-benzylpiperazine (BZP) in healthy human participants

Direct analysis in real-time tandem mass spectrometry method for the rapid screening of 11 new psychoactive substances in blood and urine

RATIONALE

With the continuous renewal of new psychoactive substances (NPS), the abuse of NPS has seriously harmed social security and public safety. The number of deaths from the abuse of NPS is increasing year by year. Therefore, there is an immediate need to develop an effective method for detecting NPS.

METHODS

Direct analysis in real-time tandem mass spectrometry (DART-MS/MS) was used to detect 11 NPS in blood and urine. The temperature of the ion source was optimized and set to 400°C. The mixture solvent of acetonitrile/methanol (4:1, v/v) was used as the precipitant. SKF-525 (2-(diethylamino)ethyl 2,2-diphenylpentanoate) was selected as the internal standard for quantification. After the pretreatment of the analytes in blood or urine, the supernatant was prepared for instrumental analysis.

RESULTS

The results indicated that the correlation coefficients (r2 ) of all analytes ranged from 0.99 to 1 in the linear range. The recoveries of 11 analytes at three spiked levels ranged between 83.4% and 110.4% in blood and between 81.7% and 108.5% in urine. The matrix effects of 11 analytes ranged between 79.5% and 109.5% in blood and between 85.0% and 109.4% in urine. The relative standard deviations of intra-day and inter-day precisions and repeatability were lower than 12.4%, 14.1%, and 14.3% in blood and lower than 11.4%, 13.9%, and 14.3% in urine, respectively.

CONCLUSION

The method established for the detection of 11 NPS could meet the needs for the rapid screening of NPS samples. The DART-MS/MS method has the advantages of being efficient, fast, and green. Therefore, it may become a promising technology for the detection of NPS in the future.

An Update on the Implications of New Psychoactive Substances in Public Health

The emergence of new psychoactive substances has earned a great deal of attention, and several reports of acute poisoning and deaths have been issued involving, for instance, synthetic opiates. In recent years, there have been profound alterations in the legislation concerning consumption, marketing, and synthesis of these compounds; rapid alert systems have also been subject to changes, and new substances and new markets, mainly through the internet, have appeared. Their effects and how they originate in consumers are still mostly unknown, primarily in what concerns chronic toxicity. This review intends to provide a detailed description of these substances from the point of view of consumption, toxicokinetics, and health consequences, including case reports on intoxications in order to help researchers and public health agents working daily in this area.

Changes in neuronal activity in rat primary cortical cultures induced by illicit drugs and new psychoactive substances (NPS) following prolonged exposure and washout to mimic human exposure scenarios

The use of new psychoactive substances (NPS) is increasing despite associated health risks and limited pharmacological and toxicological knowledge. Information is available mainly for acute effects on specific targets like monoamine transporters and receptors. Recently, we have shown the ability of several NPS and illicit drugs to modulate neuronal activity during acute exposure. While these acute measurements provide valuable information regarding the potency and possible structure-activity relationships, an exposure scenario more representative of human exposure would increase insight and aid translation to the human situation. Therefore, we investigated the effects on neuronal activity after acute (30 min) and prolonged (5 h) exposure to amphetamine-type stimulants, cathinones, hallucinogens, piperazines and cocaine using rat primary cortical cultures grown on multi-well microelectrode arrays. To investigate the reversibility of effects, activity was also measured after a washout period of 19 h. During acute exposure, all compounds concentration-dependently decreased neuronal activity. Compared to acute exposure, prolonged exposure did not further decrease neuronal activity. Following washout, effects of 3 out of 11 drugs (methamphetamine, cocaine, and benzylpiperazine) were fully reversible, whereas effects induced by MDMA, PMMA and α-PVP were partially reversible. Neuronal activity did not recover after 19 h washout following exposure to the highest concentration of MDPV, 2C-B, 25B-NBOMe, and TFMPP. On the contrary, exposure to low concentrations of methylone, and to some extent of 2C-B, increased neuronal activity after the washout period. Hazard characterization of emerging NPS should include at least an acute exposure to determine a potency rank order. Supplementing the (acute and prolonged) exposure scenario with a washout period allows investigation of the reversibility of effects. The possibility of a neuronal network to regain activity after drug exposure appears independent of drug class or IC₅₀ values for acute and prolonged exposure. Even though neuronal activity (partly) recovers after washout following exposure to most drugs, it is perturbing that complete recovery of neuronal activity is observed only for a minority of the tested drugs.

Occurrence of new psychoactive substances in wastewater of major Chinese cities

New psychoactive substances have become increasingly popular across the globe in recent years, which may cause certain public health issues. In this work, sewage-based epidemiology was applied to examine the use of two synthetic cathinones, mephedrone and methylenedioxypyrovalerone (MDPV), and three piperazines, benzylpiperazine (BZP), trifluoromethylphenylpiperazine (TFMPP), and 1-(3-Chlorophenyl)piperazine (mCPP), across China. Influent wastewater samples were collected from 36 sewage treatment plants (STPs) in 18 major cities that cover all the geographic regions of the country. Effluent samples were also collected from selected STPs to determine removal rates. Mephedrone, TFMPP, and mCPP were below detection limits in all the wastewater samples collected, indicating negligible use of these substances in China. MDPV was detected in wastewater at 13 STPs. However, its loads were <1mg/1000inh/d at most of these STPs, indicating low use of this substance. BZP was detected at all the STPs examined, with loads typically falling within the range of 3-10mg/1000inh/d. No clear geographic pattern in BZP occurrence in wastewater was identified. Since BZP in wastewater may also come from its legal sources, whether widespread occurrence of BZP means widespread abuse is yet to be confirmed. Apparent removal of MDPV by wastewater treatment was low (<25%), whereas removal of BZP was nearly complete (typically>95%).

Benzylpiperazine: "A messy drug"

Designer drugs are synthetic structural analogues/congeners of controlled substances with slightly modified chemical structures intended to mimic the pharmacological effects of known drugs of abuse so as to evade drug classification. Benzylpiperazine (BZP), a piperazine derivative, elevates synaptic dopamine and serotonin levels producing stimulatory and hallucinogenic effects, respectively, similar to the well-known drug of abuse, methylenedioxymethamphetamine (MDMA). Furthermore, BZP augments the release of norepinephrine by inhibiting presynaptic autoreceptors, therefore, BZP is a "messy drug" due to its multifaceted regulation of synaptic monoamine neurotransmitters. Initially, pharmaceutical companies used BZP as a therapeutic drug for the treatment of various disease states, but due to its contraindications and abuse potential it was withdrawn from the market. BZP imparts predominately sympathomimetic effects accompanied by serious cardiovascular implications. Addictive properties of BZP include behavioral sensitization, cross sensitization, conditioned place preference and repeated self-administration. Additional testing of piperazine derived drugs is needed due to a scarcity of toxicological data and widely abuse worldwide.

In vitro hepatotoxicity of 'Legal X': the combination of 1-benzylpiperazine (BZP) and 1-(m-trifluoromethylphenyl)piperazine (TFMPP) triggers oxidative stress, mitochondrial impairment and apoptosis

N-Benzylpiperazine (BZP) and 1-(3-trifluoromethylphenyl)piperazine (TFMPP) are two synthetic phenylpiperazine analogues that have been frequently commercialized in combination as an alternative to ecstasy ('Legal X'). Despite reports of several clinical complications following the use of these drugs in association, few studies have been conducted so far to elucidate their combined toxicity. The present study was aimed at clarifying the cytotoxic effects of mixtures of BZP and TFMPP in vitro. Human-derived HepaRG cells and primary rat hepatocytes were exposed to the drugs, individually or combined at different mixture ratios, and cytotoxicity was assessed by the MTT assay. Mixture additivity expectations were calculated by the independent action and the concentration addition (CA) models and compared with the experimental outcomes. To delineate the mechanisms underlying the elicited effects, a range of stress endpoints was evaluated, including oxidative stress, energetic imbalance, and metabolic interactions. It was observed that primary rat hepatocytes are more sensitive than HepaRG cells to the toxicity of BZP (EC₅₀ 2.20 and 6.60 mM, respectively) and TFMPP (EC₅₀ 0.14 and 0.45 mM, respectively). For all BZP-TFMPP combinations tested, CA was the most appropriate model to predict the mixture effects. TFMPP proved to act additively with BZP to produce significant hepatotoxicity (p < 0.01). Remarkably, substantial mixture effects were observed even when each drug was present at concentrations that were harmless individually. In primary hepatocytes, a small deviation from additivity (antagonism) was observed toward the upper range of the concentration-response curve. GC/MS data suggest that a metabolic interaction may be at a play, as the mixture favors the metabolism of both substances, to a significant extent in the case of BZP (p < 0.05). Also, our results demonstrate the influence of oxidative stress and energetic imbalance on these effects (increase in RNS and ROS production, decrease in intracellular GSH/GSSG, ATP depletion and mitochondrial Δψm disruption). The present work clearly demonstrates that potentially harmful interactions among BZP and TFMPP are expected when these drugs are taken concomitantly.

An In Vitro Study of the Neurotoxic Effects of N-Benzylpiperazine: A Designer Drug of Abuse

Recently, the number of new psychoactive substances has significantly increased. Despite the systematic introduction of prohibition in trade of medicinal products which mimic the effects of illegal drugs, the problem concerning this group of drugs is still important although knowledge about the mechanism of action of those types of substances is scarce. This study aimed to follow the neurotoxic effect of N-benzylpiperazine (BZP), the central nervous system psychostimulant, using the human cancer LN-18 cell model. The statistically significant elevation of LDH levels, increased mitochondrial membrane potential, decreased ATP and increased ROS production, increased levels of DNA damage marker (8-OHdG) and activation of caspases: -3 and -9 confirmed by Real-Time PCR imply the activation of mitochondrial proapoptotic pathways induced by BZP after 24 h incubation. This study is a novel, preliminary attempt to explain the toxicity of one of the most popular designer drug of abuse at the cellular level.

Using fMRI to compare the effects of benzylpiperazine with dexamphetamine - Their differences during the Stroop paradigm

RATIONALE

Benzylpiperazine (BZP) has been found to increase neural activation in the dorsal striatum when compared to placebo in response to a Stroop paradigm, in addition, subjective effects have been compared to dexamphetamine (DEX). Despite their similarities, the two have not been directly compared in respect to their effects on selective attention and inhibition.

OBJECTIVES

To use a double-blind placebo-controlled crossover study to compare the acute effects of BZP and DEX on executive function using functional magnetic resonance imaging (fMRI) and an event-related Stroop task.

METHODS

Eleven healthy participants aged 18-40 years undertook the Stroop task 90[Formula: see text]min after taking an oral dose of either BZP (200[Formula: see text]mg), DEX (20[Formula: see text]mg) or placebo.

RESULTS

BZP induced a greater increase in activation than DEX in the inferior frontal gyrus (IFG) during the Stroop task. DEX increased BOLD signal in the thalamus and decreased it in the IFG in comparison to placebo.

CONCLUSION

Despite BZP and DEX reportedly inducing similar subjective effects, there are different patterns of neural activation. We believe this differential activity is due to pharmacological differences in their receptor binding profiles and that subsequent inhibitory effects might be due to their direct effect on dopaminergic activity.

Acute effects of the designer drugs benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) using functional magnetic resonance imaging (fMRI) and the Stroop task--a pilot study

RATIONALE

A novel group of designer drugs containing benzylpiperazine (BZP) and/or trifluoromethylphenylpiperazine (TFMPP) have been available worldwide for more than a decade; however, their effects on human brain function have not been extensively described.

OBJECTIVES

In a double-blind, placebo-controlled crossover study, the acute effects of BZP and TFMPP (alone and in combination) on the neural networks involved in executive function were investigated using an event-related Stroop functional magnetic resonance imaging (fMRI) paradigm.

METHODS

Thirteen healthy participants aged 18-40 years undertook the Stroop task 90 min after taking an oral dose of either BZP (200 mg), TFMPP (either 50 or 60 mg), BZP + TFMPP (100 + 30 mg) or placebo. A change in activity in neural regions reflects an increase in local demand for oxygen, due to an increase in neuronal activity.

RESULTS

Relative to placebo, an increase in neural activation was observed in the dorsal striatum following BZP, and in the thalamus following TFMPP, when performing the Stroop task.

CONCLUSION

These data suggest that additional compensatory resources were recruited to maintain performance during the Stroop task. When BZP and TFMPP were administered together, both the dorsal striatum and thalamus were activated. However, the combination of BZP/TFMPP attenuated activation in the caudate, possibly due to TFMPP's indirect effects on dopamine release via 5HT2C receptors.

"Legal Highs"--An Emerging Epidemic of Novel Psychoactive Substances

During the last decade, there has been an increase in the availability and use of novel psychoactive substances (NPS), also known as "legal highs," across the world. They include a wide range of products, from natural plant-originated substances to synthetic compounds, that can be purchased both online and from high street retailers. "Legal highs" mimic psychoactive effects of illicit drugs of abuse. However, they are claimed to consist of compounds that are legal to sell, possess, and use, often labeled as "not for human consumption" to circumvent drug abuse legislation. Based on the spectrum of their actions on cognitive processes, mood, and behavior, "legal highs" can be classified into four basis categories: amphetamine- and ecstasy-like stimulants, synthetic cannabinoids (SCs), hallucinogenic/dissociative, and opioid-like compounds. NPS may, however, exhibit a combination of these actions due to their designed chemical structure. Although the prevalence and pattern of NPS use differ between various countries, the most popular groups are SCs and psychostimulants, described in this chapter. Currently, there is limited information available on the potential acute toxicity (harms) associated with the use of these substances. However, the number of intoxicated people presenting with emergencies is constantly increasing, providing evidence that negative health and social consequences may indeed seriously affect recreational and chronic users.

The impact of the prohibition of benzylpiperazine (BZP) "legal highs" on the availability, price and strength of BZP in New Zealand

BACKGROUND

Legal highs containing benzylpiperazine (BZP) were widely sold in New Zealand until BZP was prohibited in 2008. We examined the impact the prohibition had on the availability and price of BZP over following years.

METHODS

Two national population surveys of BZP use were conducted in 2006 and 2009. Four annual targeted surveys of frequent drug users (FDU) were conducted from 2007-2010. Availability and price measures were obtained. Inflation-adjusted real retail prices were calculated. Other drug markets were monitored as quasi-controls.

RESULTS

The proportion of BZP users from the general population who considered the availability of BZP to be 'very easy' declined from 76% in 2006 to 21% in 2009. The proportion who thought BZP had become 'harder' to obtain increased from 5% in 2006 to 71% in 2009. The proportion who reported the price of BZP was 'higher' increased from 27% in 2006 to 51% in 2009. FDU who considered the availability of BZP to be 'very easy' declined from 98% in 2007 to 15% in 2008, and then increased to 42% by 2010. The real retail price of a BZP tablet increased from $9.86 in 2007 to $15.83 in 2010. The proportion who considered the price of BZP to be 'increasing' rose from 3% in 2007 to 47% in 2010.

CONCLUSIONS

The availability of BZP declined immediately following its prohibition. Availability recovered in subsequent years, but not to the pre-prohibition legal level. The price of BZP increased slowly over a number of years following the prohibition.

A critical first assessment of the new pre-market approval regime for new psychoactive substances (NPS) in New Zealand

BACKGROUND

New Zealand has recently attempted to address the underlying drivers of the escalating new psychoactive substances (NPS) ('legal highs') problem by establishing the world's first pre-market approval regulatory regime for NPS. NPS products which can be shown with clinical trial data to pose a 'low risk' of harm will be approved for legal manufacture and sale.

AIMS AND METHOD

This paper critically assesses the new regime, drawing on experience of the pharmaceutical sector and legal BZP market.

FINDINGS

A number of characteristics of the recreational use of NPS may not be well addressed by standard medical clinical trials, including binge use, polydrug use, use by vulnerable groups and high-risk modes of administration. The overt advertising and covert promotion of approved NPS products on the internet may make them fairly visible to young people. The black market for unapproved NPS may be difficult to suppress given that unapproved NPS will be physically identical to approved NPS. If the legal market for NPS encourages the use of NPS, alcohol and other drugs there may be an increase in drug-related harm. Alternatively, if the legal NPS market reduces the use of more harmful drugs, there may be a considerable public health benefit.

CONCLUSIONS

The clinical trials required for NPS products should address the characteristics of recreational NPS use. Enforcement resources and technical solutions are required to clearly distinguish legal NPS products. The impact the new NPS regime has on other drug use is a key issue and demands further study.

Toxicology and Management of Novel Psychoactive Drugs

Health care providers are seeing an increased number of patients under the influence of several new psychoactive drug classes. Synthetic cannabinoids, cathinones, and piperazines are sought by users for their psychoactive effects, perceived safety profile, minimal legal regulations, and lack of detection on routine urine drug screening. However, these drugs are beginning to be recognized by the medical community for their toxic effects. The neuropsychiatric and cardiovascular toxicities are among the most common reasons for emergency medical treatment, which in some cases, can be severe and even life-threatening. Management strategies are often limited to supportive and symptomatic care due to the limited published data on alternative treatment approaches. The purpose of this article is to offer health care providers, emergency medical personnel in particular, an awareness and understanding of the dangers related to some of the new psychoactive drugs of abuse. The background, pharmacology, toxicity, management, detection, and legal status of each class will be discussed.

Recent developments in urinalysis of metabolites of new psychoactive substances using LC–MS

In the last decade, an ever-increasing number of new psychoactive substances (NPSs) have appeared on the recreational drug market. To account for this development, analytical toxicologists have to continuously adapt their methods to encompass the latest NPSs. Urine is the preferred biological matrix for screening analysis in different areas of analytical toxicology. However, the development of urinalysis procedures for NPSs is complicated by the fact that generally little or no information on urinary excretion patterns of such drugs exists when they first appear on the market. Metabolism studies are therefore a prerequisite in the development of urinalysis methods for NPSs. In this article, the literature on the urinalysis of NPS metabolites will be reviewed, focusing on articles published after 2008.

Piperazine designer drugs induce toxicity in cardiomyoblast h9c2 cells through mitochondrial impairment

Abuse of synthetic drugs is widespread among young people worldwide. In this context, piperazine derived drugs recently appeared in the recreational drug market. Clinical studies and case-reports describe sympathomimetic effects including hypertension, tachycardia, and increased heart rate. Our aim was to investigate the cytotoxicity of N-benzylpiperazine (BZP), 1-(3-trifluoromethylphenyl) piperazine (TFMPP), 1-(4-methoxyphenyl) piperazine (MeOPP), and 1-(3,4-methylenedioxybenzyl) piperazine (MDBP) in the H9c2 rat cardiac cell line. Complete cytotoxicity curves were obtained at a 0-20 mM concentration range after 24 h incubations with each drug. The EC50 values (μM) were 343.9, 59.6, 570.1, and 702.5 for BZP, TFMPP, MeOPP, and MDBP, respectively. There was no change in oxidative stress markers. However, a decrease in total GSH content was noted for MDBP, probably due to metabolic conjugation reactions. All drugs caused significant decreases in intracellular ATP, accompanied by increased intracellular calcium levels and a decrease in mitochondrial membrane potential that seems to involve the mitochondrial permeability transition pore. The cell death mode revealed early apoptotic cells and high number of cells undergoing secondary necrosis. Among the tested drugs, TFMPP seems to be the most potent cytotoxic compound. Overall, piperazine designer drugs are potentially cardiotoxic and support concerns on risks associated with the intake of these drugs.

Benzylpiperazine-induced acute delirium in a patient with schizophrenia and an incidental temporal meningioma

Benzylpiperazine is a psychotropic compound that has been widely available until recently from licensed premises such as ‘head shops’. This report describes a case of a 48 year old man with schizophrenia who developed an acute delirium secondary to benzylpiperazine use, although he initially presented as a diagnostic conundrum. Investigation of his delirium unearthed a temporal meningioma which appears to be an incidental finding. This is the first documented case of delirium due to benzylpiperazine use. Benzylpiperazine has significant abuse potential and psychiatric complications. Its sale and possession have recently been made illegal in Ireland, which may limit its abuse in the future.

Analysis of amphetamine-type substances and piperazine analogues using desorption electrospray ionisation mass spectrometry

RATIONALE

Although amphetamine-type substances (ATS) have been investigated extensively in recent years, scarce data is available on screening tests for piperazine analogues. The need for a universal technique capable of detecting an extensive range of drug compounds becomes increasingly important with the continued emergence of novel drug analogues.

METHODS

Desorption electrospray ionisation mass spectrometry (DESI-MS) is a technique that allows examination of compounds in drug materials directly from ambient surfaces. In this study, DESI-MS was utilised in the analysis of ATS including amphetamine (AP), methylamphetamine (MA), 3,4-methylenedioxymethylamphetamine (MDMA), N,N-dimethylamphetamine (DMA), 4-methoxyamphetamine (PMA) and 4-methoxymethylamphetamine (PMMA), and piperazine analogues including 1-benzylpiperazine (BZP), 1-[3-(trifluoromethyl)phenyl]piperazine (TFMPP), 1-(3-chlorophenyl)piperazine (mCPP) and 1-(4-methoxyphenyl)piperazine (MeOPP). Semi-porous polytetrafluoroethylene (PTFE or Teflon) sheets welled with a 3 mm hole punch were used to contain the 2 μL liquid sample (spot size 7 mm(2) ).

RESULTS

The limits of detection (LODs) of these compounds using DESI-MS were determined to be in the range 0.02-2.80 µg/mm(2) . The intra-day and inter-day precision of the technique were <25% and <33%, respectively. DESI-MS was successful in determining the compound of interest and reaction by-products and impurities in the samples tested (such as 1,4-dibenzylpiperazine in BZP samples) with the exception of those present in trace amounts. The effects of common adulterants on the detectability of MA were evaluated. The addition of magnesium stearate to MA significantly enhanced the signal response.

CONCLUSIONS

This work has demonstrated the applicability of DESI-MS in the screening and profiling of MDMA, PMMA, BZP, TFMPP, mCPP, MeOPP as well as other complex mixtures.

Clinical and pharmacological aspects of bath salt use: a review of the literature and case reports

Bath salts are designer drugs with stimulant properties that are a growing medical and psychiatric concern due to their widespread availability and use. Although the chemical compounds in the mixtures referred to as "bath salts" vary, many are derivatives of cathinone, a monoamine alkaloid. Cathinones have an affinity for dopamine, serotonin, and norepinephrine synapses in the brain. Because of the strong selection for these neurotransmitters, these drugs induce stimulating effects similar to those of methamphetamines, cocaine, and 3,4-methylenedioxy-N-methylamphetamine (MDMA). Much of the emerging information about bath salts is from emergency department evaluation and treatment of severe medical and neuropsychiatric adverse outcomes. This review consists of a compilation of case reports and describes the emergent literature that illustrates the chemical composition of bath salts, patterns of use, administration methods, medical and neuropsychiatric effects, and treatments of patients with bath salt toxicity.

The impact of the prohibition of benzylpiperazine (BZP) 'legal highs' on the prevalence of BZP, new legal highs and other drug use in New Zealand

BACKGROUND

Benzylpiperazine (BZP) is the psychoactive ingredient in a range of 'legal highs' sold worldwide. BZP was prohibited in New Zealand in 2008.

AIM

To investigate the impact of the prohibition of BZP legal highs on the prevalence of BZP, replacement legal highs and other drugs.

METHODS

A population survey of BZP and other drugs was conducted in 2006 (while BZP was legal) and repeated in 2009 (+12 months after BZP was prohibited). Respondents were asked to provide the reason(s) why they had stopped using BZP. Annual surveys of frequent drug users were conducted from 2006 to 2010.

RESULTS

Last year prevalence of BZP among the general population fell from 15.3% in 2006 to 3.2% in 2009. The most common reasons for stopping BZP use in 2008 were 'it's illegal now' (43%), 'just experimenting' (26%), 'don't know where to get it now it's illegal' (24%) and 'bad hangover effect' (18%). Three per cent of the general population had used any new legal high in 2009. Use of BZP declined among frequent methamphetamine users from 32% in 2006 to 7% in 2010; among frequent ecstasy users from 65% in 2006 to 11% in 2010; and among frequent injecting drug users from 30% in 2007 to 20% in 2010. The use of new legal highs in 2010 was lower than the former use of BZP in 2006.

CONCLUSIONS

Unpleasant side-effects and the prohibition contributed to a decline in BZP use. The overall level of legal high use was lower following the prohibition of BZP.

Estrogenic effects and their action mechanism of the major active components of party pill drugs

Benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) are commonly used constituents of party pill drugs. They are reported to induce psychoactive effects such as euphoria and provide effects similar with other illicit drugs such as methylenedioxymethamphetamine (MDMA). A great deal of evidence has proven that party pills, as alternatives for MDMA, exert harmful effects on users. However, their toxicological effects have not been fully understood and endocrine disruptive effects are still unknown. In this study, we identified estrogenic effects of BZP and TFMPP by using in vitro and in vivo assays. BZP and TFMPP stimulated cell proliferation in a dose-dependent manner, while co-treatment with tamoxifen and BZP or TFMPP showed a decrease of E(2)-induced cell proliferation. In an estrogen sensitive reporter gene assay, BZP and TFMPP significantly increased transcriptional activities of party pill drugs. In addition, ER-related genes, PR and pS2, were significantly stimulated by BZP and TFMPP. These results indicated that BZP and TFMPP could have estrogenic activities related to the ER-mediated pathway. Unlike the in vitro assay results, BZP and TFMPP did not show significant effects on weight increase in a rodent uterotrophic assay. However, further studies would be necessary to verify the estrogenic activities of BZP and TFMPP by a chronic exposure animal study.

Piperazine compounds as drugs of abuse

Synthetic drugs are among the most commonly abused drugs in the world. This abuse is widespread among young people, especially in the dance club and rave scenes. Over the last several years, piperazine derived drugs have appeared, mainly available via the internet, and sold as ecstasy pills or under the names of "Frenzy", "Bliss", "Charge", "Herbal ecstasy", "A2", "Legal X" and "Legal E". Although in the market piperazine designer drugs have the reputation of being safe, several experimental and epidemiological studies indicate risks for humans. Piperazine designer drugs can be divided into two classes, the benzylpiperazines such as N-benzylpiperazine (BZP) and its methylenedioxy analogue 1-(3,4-methylenedioxybenzyl)piperazine (MDBP), and the phenylpiperazines such as 1-(3-chlorophenyl)piperazine (mCPP), 1-(3-trifluoromethylphenyl)piperazine (TFMPP), and 1-(4-methoxyphenyl)piperazine (MeOPP). Toxicokinetic properties, including metabolic pathways, actions and effects in animals and humans, with some hypothesis of mechanism of action, and analytical approaches for the identification of these drugs are summarized in this review.

Linking the pharmacological content of ecstasy tablets to the subjective experiences of drug users

RATIONALE

Most studies on the subjective effects of ecstasy are based on the assumption that the substance that was taken is 3,4-methylenedioxymethamphetamine (MDMA). However, many tablets sold as ecstasy contain other substances and MDMA in varying doses. So far, few attempts have been made to take this into account while assessing subjective effects.

OBJECTIVES

This study aims to link the pharmacological content of tablets sold as ecstasy to the subjective experiences reported by ecstasy users.

METHODS

Self-reported effects on ecstasy tablets were available from 5,786 drug users who handed in their tablets for chemical analysis at the Drug Information and Monitoring System (DIMS) in the Netherlands. Logistic regression was employed to link the pharmacological content of ecstasy tablets to the self-reported subjective effects and compare effects with MDMA to other substances present.

RESULTS

MDMA showed a strong association with desirable subjective effects, unparalleled by any other psychoactive substance. However, the association of MDMA was dose-dependent, with higher doses (>120 mg/tablet) likely to evoke more adverse effects. The novel psychostimulants mephedrone and p-fluoroamphetamine were considered relatively desirable, whereas meta-chlorophenylpiperazine (mCPP) and p-methoxymethamphetamine (PMMA) were strongly associated with adverse subjective effects. Also, 3,4-methylene-dioxyamphetamine (MDA) and benzylpiperazine (BZP) were not appreciated as replacement for MDMA.

CONCLUSION

Linking the pharmacological content of ecstasy sold on the street to subjective experiences contributes to a better understanding of the wide range of subjective effects ascribed to ecstasy and provides a strong rationale for the prolonged endurance of MDMA as the key ingredient of the ecstasy market.

Current awareness of piperazines: pharmacology and toxicology

Although many piperazine derivatives exist, only a limited number have been studied, whereby they have been found to be generally stimulant in nature resulting from dopaminergic, noradrenergic, and predominantly serotoninergic effects in the brain. Reported toxic effects include agitation, anxiety, cardiac symptoms (e.g. tachycardia) and sometimes seizures. As for many drugs, they are primarily metabolized by cytochrome P450 with subsequent possible glucuronidation and/or sulfation. Their abuse has been relatively recently observed in the last decade with only a few identified in biological fluid (primarily 1-benzylpiperazine (BZP) and 1-(3-trifluoromethylphenyl)piperazine (3-TFMPP)) despite publications of a number of analytical methods. Even when detected, however, the toxicological significance of their presence is often difficult to ascertain as many cases involve other drugs as well as a wide and overlapping range of concentrations found in blood (both in life and after death). This paper reviews the current pharmacological and toxicological information for piperazine derivatives and also includes new ante-mortem and post-mortem blood data.

The clinical toxicology of the designer "party pills" benzylpiperazine and trifluoromethylphenylpiperazine

INTRODUCTION

Benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) are synthetic phenylpiperazine analogues. BZP was investigated as a potential antidepressant in the early 1970s but was found unsuitable for this purpose. More recently, BZP and TFMPP have been used as substitutes for amfetamine-derived designer drugs. They were legally available in a number of countries, particularly in New Zealand, and were marketed as party pills, but are now more heavily regulated. This article will review the mechanisms of toxicity, toxicokinetics, clinical features, diagnosis, and management of poisoning due to BZP and TFMPP.

METHODS

OVID MEDLINE and ISI Web of Science were searched systematically for studies on BZP and TFMPP and the bibliographies of identified articles were screened for additional relevant studies including nonindexed reports. Nonpeer-reviewed sources were also accessed. In all, 179 papers excluding duplicates were identified and 74 were considered relevant.

MECHANISMS OF ACTION

BZP and TFMPP have stimulant and amfetamine-like properties. They enhance the release of catecholamines, particularly of dopamine, from sympathetic nerve terminals, increasing intra-synaptic concentrations. The resulting elevated intra-synaptic monoamine concentrations cause increased activation of both central and peripheral α- and β-adrenergic postsynaptic receptors. BZP has primarily dopaminergic and noradrenergic action while TFMPP has a more direct serotonin agonist activity.

TOXICOKINETICS

There is limited information on the kinetics of these drugs. Following ingestion, peak plasma concentrations are reached after 60 to 90 min. Both drugs would be expected to cross the blood brain barrier and they are metabolized mainly by hydroxylation and N-dealkylation catalyzed by cytochrome P450 and catechol-o-methyl transferase enzymes. In humans, only small amounts of both BZP and TFMPP are excreted in the urine, suggesting a low bioavailability. The serum half-lives of BZP and TFMPP are relatively short with elimination being essentially complete in 44 h for BZP and 24 h for TFMPP.

CLINICAL FEATURES

These compounds can cause harmful effects when taken recreationally. Commonly reported features include palpitations, agitation, anxiety, confusion, dizziness, headache, tremor, mydriasis, insomnia, urine retention, and vomiting. Seizures are induced in some patients even at low doses. Severe multiorgan toxicity has been reported, though fatalities have not been recorded conclusively.

MANAGEMENT

Supportive care including the termination of seizures is paramount, with relief of symptoms usually being provided by benzodiazepines alone.

CONCLUSIONS

BZP and TFMP can cause sympathomimetic effects in the intoxicated patient. Appropriate, symptom-directed supportive care should ensure a good recovery.

Determining the subjective and physiological effects of BZP combined with TFMPP in human males

RATIONALE

‘Party Pills’ containing benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) have been used in a recreational context since the 1990s and, prior to April 2008, were legally available in New Zealand. Taken together, they have been reported to produce a ‘high’ similar to that produced by 3,4-methylenedioxymethamphetamine (MDMA).

OBJECTIVES

There has been little research on the subjective effects of piperazines in humans. The purpose of this study is to further investigate the subjective and physiological responses following an oral dose of BZP combined with TFMPP in males.

METHODS

In a randomised, double-blind, placebo-controlled study the subjective and physiological effects of BZP/TFMPP were investigated in 36 healthy, non-smoking males (mean age 22 ± 4 years). Participants were tested before and approximately 120 min after administration of a single dose of placebo (n = 16) or 100/30 mg BZP/TFMPP (n = 20). Participants were required to comment on the subjective effects using three rating scales—the Addiction Research Centre Inventory (ARCI), the Visual Analogue Scale (VAS) and the Profile of Mood States (POMS). Participants' blood pressure, heart rate and body temperature were also measured.

RESULTS

Statistical analysis using repeated-measures analysis of variance (ANOVA) and planned comparisons revealed that BZP/TFMPP significantly increases blood pressure and heart rate (p < 0.05). Likewise, the subjective rating scales revealed that BZP/TFMPP has significant dexamphetamine-like effects, increases dysphoria and feelings of self-confidence (p < 0.05).

CONCLUSION

These physiological and subjective data reflect clear similarities between the effects of BZP/TFMPP and commonly known stimulants such as dexamphetamine and MDMA.

BZP-party pills: a review of research on benzylpiperazine as a recreational drug

BACKGROUND

BZP-party pills are yet another 'designer drug' which mimics the stimulant qualities of amphetamines and MDMA/Ecstasy. As legal markets for the substance have developed in the last decade (especially amongst young people) so has public and governmental concern.

METHODS

This article provides a summary of the available international research on benzylpiperazine (BZP) and its popular use in the compound form known as 'party pills'. Through performing an analysis of the available medical and social scientific literature, the review outlines current knowledge on the compound, the prevalence of usage of BZP-party pills, as well as the associated harms, risks and rationales for use of the drug.

RESULTS

Despite moves towards legislative control of BZP-party pills, the evidence presented suggests limited social and health harms associated with the drug, although research on long term effects is a significant gap in the literature. It also remains inconclusive as to whether BZP-party pills act as a 'gateway' to illegal drugs or, conversely, play a role in harm reduction with illegal drug users turning to legal alternatives; there is some evidence for both positions.

CONCLUSION

With increasing controls of BZP-party pills, and with the increasing numbers of 'legal highs' and new designer drugs on the market, we conclude that new legal alternatives will continue to surface to replace the drug in the future. Considering a harm reduction approach to drug taking, it is suggested that policy makers consider the creation of a legal holding category which restricts and regulates the market in legal highs whilst the social and health harms associated with each drug can be thoroughly investigated.

Multiorgan failure from 1-benzylpiperazine ingestion--legal high or lethal high?

INTRODUCTION

1-benzylpiperazine (BZP) is synthetic stimulant. It was legal and openly sold in New Zealand before October 1, 2008. Two cases of life-threatening toxicity associated with BZP use are reported in detail in this article.

CASES

Case one describes an adult female who developed status epilepticus, hyperthermia, disseminated intravascular coagulation, rhabdomyolysis, and renal failure associated with a BZP ingestion. Case two developed a similar pattern of toxicity from the combined use of BZP and 3,4-methylenedioxy-N-methylamphetamine. Both cases required prolonged hospital care but survived.

DISCUSSION

There have been reports of deaths associated with the combined ingestion of BZP and 3,4-methylenedioxy-N-methylamphetamine. The effects may possibly be synergistic when co-ingested. Case one suggests that BZP alone has the potential to cause serious sympathomimetic toxicity.

Metabolic interactions with piperazine-based ‘party pill’ drugs

Objectives

‘Party pills’ have found use worldwide as a substitute for amphetamine-derived designer drugs. Whilst some information exists about the metabolism of these drugs, there is little information about their ability to inhibit the metabolism of co-administered drugs. This study aimed to determine whether predictions can be made about global interactions between ‘party pills’ constituents and other drugs metabolised by the same cytochrome P450 (CYP) isoenzymes.

Methods

The inhibitory effects of seven benzyl and phenyl piperazines were measured in microsomal incubation assays of probe substrates for five major CYP isoenzymes. In addition, the metabolism of benzylpiperazine and trifluoromethylphenylpiperazine, the two most commonly used constituents of ‘party pills’, was investigated using human liver microsomes assays and known inhibitors of CYP isoenzymes.

Key findings

All piperazine analogues tested showed significant inhibitory activity against most, if not all, isoenzymes tested. The metabolism of benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) involved CYP2D6, CYP1A2 and CYP3A4. Furthermore, BZP and TFMPP inhibited each other's metabolism.

Conclusions

Fluorophenylpiperazine, methoxyphenylpiperazine, chlorophenylpiperazine, methylbenzylpiperazine and methylenedioxybenzylpiperazine had significant inhibitory effects on CYP2D6, CYP1A2, CYP3A4, CYP2C19 and CYP2C9 isoenzymes but each piperazine had a different inhibitory profile. The metabolic interaction between BZP and TFMPP may have clinical implications, as these agents are often combined in ‘party pills’.