The action of trelibet, a new antidepressive agent on [3H]noradrenaline release from rabbit pulmonary artery

Comparing the dopaminergic neurotoxic effects of benzylpiperazine and benzoylpiperazine

Benzylpiperazine has been designated as Schedule I substance under the Controlled Substances Act by Drug Enforcement Administration. Benzylpiperazine is a piperazine derivative, elevates both dopamine and serotonin extracellular levels producing stimulatory and hallucinogenic effects, respectively, similar to methylenedioxymethamphetamine (MDMA). However, the comparative neurotoxic effects of Piperazine derivatives (benzylpiperazine and benzoylpiperazine) have not been elucidated. Here, piperazine derivatives (benzylpiperazine and benzoylpiperazine) were synthesized in our lab and the mechanisms of cellular-based neurotoxicity were elucidated in a dopaminergic human neuroblastoma cell line (SH-SY5Y). We evaluated the in vitro effects of benzylpiperazine and benzoylpiperazine on the generation of reactive oxygen species, lipid peroxidation, mitochondrial complex-I activity, catalase activity, superoxide dismutase activity, glutathione content, Bax, caspase-3, Bcl-2 and tyrosine hydroxylase expression. Benzylpiperazine and benzoylpiperazine induced oxidative stress, inhibited mitochondrial functions and stimulated apoptosis. This study provides a germinal assessment of the neurotoxic mechanisms induced by piperazine derivatives that lead to neuronal cell death.

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drug for the treatment of various disease states, but due to its contraindications and abuse potential it was withdrawn from the market.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.

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.

Acute effects of BZP, TFMPP and the combination of BZP and TFMPP in comparison to dexamphetamine on an auditory oddball task using electroencephalography: a single-dose study

RATIONALE

Piperazine-based designer drugs such as benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) have been marketed and sold as legal alternatives to dexamphetamine and 3,4-methylenedioxymethamphetamine (MDMA) until 2008 in New Zealand. When administered in combination, BZP + TFMPP have been reported to produce drug-drug synergism in rodents by stimulating the release of dopamine and serotonin.

OBJECTIVES

This study was to evaluate the acute event-related potential effects of BZP, TFMPP or the combination of BZP + TFMPP compared with dexamphetamine in young healthy male adults.

METHODS

A double-blind, randomised, placebo-controlled study investigated the effects of BZP, TFMPP, the combination of BZP + TFMPP, and dexamphetamine on the event-related potentials during an auditory oddball task. Healthy, right-handed males were given a single oral dose of either BZP (200 mg), TFMPP (60 mg), a combination of BZP + TFMPP (100/30 mg), dexamphetamine (20 mg) or placebo (lactose) and tested both before and 120 min after drug administration.

RESULTS

A single dose of either TMFPP (t = -2.29, p = 0.03) or dexamphetamine (t = -2.33, p = 0.02) significantly reduced the P300 amplitude. A similar trend was also found in BZP. In contrast, BZP and TFMPP in combination has no effect. Neither P300 latency nor the mean reaction time was affected by any of the drug treatments. In addition, neither the P100 nor the P200 component was significantly affected following any of the drug treatments.

CONCLUSIONS

A single oral dose of BZP or TFMPP, but not the combination of BZP/TFMPP, affected auditory sensory-evoked P300 potential in a manner similar to dexamphetamine.

Low resolution and high resolution MS for studies on the metabolism and toxicological detection of the new psychoactive substance methoxypiperamide (MeOP)

In 2013, the new psychoactive substance methoxypiperamide (MeOP) was first reported to the European Monitoring Centre for Drug and Drug Addiction. Its structural similarity to already controlled piperazine designer drugs might have contributed to the decision to offer MeOP for online purchase. The aims of this work were to identify the phase I/II metabolites of MeOP in rat urine and the human cytochrome P450 (CYP) isoenzymes responsible for the initial metabolic steps. Finally, the detectability of MeOP in rat urine by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography coupled with multistage mass spectrometry (LC-MS(n)) standard urine screening approaches (SUSAs) was evaluated. After sample preparation by cleavage of conjugates followed by extraction for elucidating phase I metabolites, the analytes were separated and identified by GC-MS as well as liquid chromatography-high resolution-tandem mass spectrometry (LC-HR-MS/MS). For detection of phase II metabolites, the analytes were separated and identified after urine precipitation followed by LC-HR-MS/MS. The following metabolic steps could be postulated: hydrolysis of the amide, N-oxide formation, N- and/or O-demethylation, oxidation of the piperazine ring to the corresponding keto-piperazine, piperazine ring opening followed by oxidation of a methylene group to the corresponding imide, and hydroxylation of the phenyl group. Furthermore, N-acetylation, glucuronidation and sulfation were observed. Using human CYPs, CYP1A2, CYP2C19, CYP2D6, and/or CYP3A4 were found to catalyze N-oxide formation and N-, O-demethylation and/or oxidation. Mostly MeOP and N-oxide-MeOP but to a minor degree also other metabolites could be detected in the GC-MS and LC-MS(n) SUSAs.

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.

Pharmacological profiles of aminoindanes, piperazines, and pipradrol derivatives

Aminoindanes, piperazines, and pipradrol derivatives are novel psychoactive substances found in "Ecstasy" tablets as replacements for 3,4-methylenedioxymethamphetamine (MDMA) or substances sold as "ivory wave." The pharmacology of these MDMA- and methylphenidate-like substances is poorly known. We characterized the pharmacology of the aminoindanes 5,6-methylenedioxy-2-aminoindane (MDAI), 5-iodoaminoindane (5-IAI), and 2-aminoindane (2-AI), the piperazines meta-chlorophenylpiperazine (m-CPP), trifluoromethylphenylpiperazine (TFMPP), and 1-benzylpiperazine (BZP), and the pipradrol derivatives desoxypipradrol (2-diphenylmethylpiperidine [2-DPMP]), diphenylprolinol (diphenyl-2-pyrrolidinemethanol [D2PM]), and methylphenidate. We investigated norepinephrine (NE), dopamine (DA), and serotonin (5-hydroxytryptamine [5-HT]) uptake inhibition using human embryonic kidney 293 (HEK 293) cells that express the respective human monoamine transporters (NET, DAT, and SERT). We also evaluated the drug-induced efflux of NE, DA, and 5-HT from monoamine-preloaded cells and the binding affinity to monoamine transporters and receptors, including trace amine-associated receptor 1 (TAAR1). 5-IAI and MDAI preferentially inhibited the SERT and NET and released 5-HT. 2-AI interacted with the NET. BZP blocked the NET and released DA. m-CPP and TFMPP interacted with the SERT and serotonergic receptors. The pipradrol derivatives were potent and selective catecholamine transporter blockers without substrate releasing properties. BZP, D2PM, and 2-DPMP lacked serotonergic activity and TAAR1 binding, in contrast to the aminoindanes and phenylpiperazines. In summary, all of the substances were monoamine transporter inhibitors, but marked differences were found in their DAT vs. SERT inhibition profiles, release properties, and receptor interactions. The pharmacological profiles of D2PM and 2-DPMP likely predict a high abuse liability.

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.

Randomised double-blind, placebo-controlled trial of the effects of the 'party pills' BZP/TFMPP alone and in combination with alcohol

The objective of this study was to determine the clinical effects of party pills containing benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) when taken alone and in combination with alcohol. The study was a randomised, double-blind, placebo-controlled trial conducted in a hospital-based clinic in Wellington, New Zealand. Thirty-five volunteers who had previously used party pills containing BZP were included in this trial. Participants received one of the following four treatments: 300 mg/74 mg BZP/TFMPP and placebo, 300 mg/74 mg BZP/TFMPP and 57.6 g (6 units) alcohol, placebo and 57.6 g (6 units) alcohol and double placebo. The primary outcome variable was a measure of driving performance, the standard deviation of lateral position (SDLP) measured at 6.5 h. Secondary measures included adverse events, cardiovascular effects, psychological function and delayed effects on sleep. The study was stopped early, after 35 of the planned 64 subjects had undertaken testing, because of severe adverse events that occurred in four of 10 BZP/TFMPP-only subjects, three of seven combined BZP/TFMPP and alcohol subjects, none of the 6 placebo subjects, and none of the 12 alcohol-only subjects. The overall rate of severe adverse events (defined as causing considerable interference with usual activity and/or rated by subject as severe) in those receiving BZP/TFMPP was seven of 17 (41.2%, 95% CI 18.4-67.1). The severe events included agitation, anxiety, hallucinations, vomiting, insomnia and migraine. BZP/TFMPP significantly improved the driving performance, decreasing SDLP at -4.2 cm (95% CI -6.8 to -1.6, P = 0.002). The effect of alcohol was to increase SDLP: 2.3 cm (95% CI -0.3 to 4.9, P = 0.08). BZP/TFMPP also resulted in increased heart rate and blood pressure and in difficulty in getting to sleep. BZP/TFMPP alone or with alcohol carries a significant risk of severe adverse events when taken in similar doses to those recommended by manufacturers.

Determining the subjective and physiological effects of BZP on human females

BACKGROUND

"Party pills" containing benzylpiperazine (BZP) used to be widely and legally available as recreational drugs in New Zealand. There are only two published trials on human subjects (1973), which suggested that 100 mg of BZP produced subjective and physiological effects similar to 10 mg of dexamphetamine. The purpose of this study is to further investigate the subjective and physiological responses to BZP in females.

METHODS/STUDY DESIGN

In a randomised, double blind, placebo-controlled study, the subjective and physiological effects of BZP were investigated in 27 healthy, right-handed non-smoking females (mean age 22 +/- 3 years). Two groups were tested before and approximately 120 minutes after administration of a single oral dose of either 200 mg BZP (n = 14) or placebo (n = 13). Participants were required to comment on the subjective effects of BZP using three rating scales-the Addiction Centre for Research Inventory, the Profile of Mood States and the Visual Analogue Scale. Participants' blood pressure, heart rate and temperature were also measured.

RESULTS/FINDINGS

Statistical analysis using a split-plot analysis of variance and t tests revealed that BZP significantly increases blood pressure and heart rate (p < 0.05) Likewise, the subjective reports revealed that BZP has significant stimulant effects, increases euphoria and dysphoria and increases sociability and drug liking (p < 0.05).

DISCUSSION/INTERPRETATION

Physiological and subjective data reflected a clear similarity between the effects of BZP and those of other commonly known stimulants such as amphetamine and 3,4-methylenedioxymethamphetamine.

Review article: amphetamines and related drugs of abuse

Acute amphetamine toxicity is a relatively common clinical scenario facing the Australasian emergency medicine physician. Rates of use in Australasia are amongst the highest in the world. Clinical effects are a consequence of peripheral and central adrenergic stimulation producing a sympathomimetic toxidrome and a spectrum of central nervous system effects. Assessment aims to detect the myriad of possible complications related to acute amphetamine exposure and to institute interventions to limit associated morbidity and mortality. Meticulous supportive care aided by judicial use of benzodiazepines forms the cornerstone of management. Beta blockers are contraindicated in managing cardiovascular complications. Agitation and hyperthermia must be treated aggressively. Discharge of non-admitted patients from the emergency department should only occur once physiological parameters and mental state have returned to normal. All patients should receive education regarding the dangers of amphetamine use.

Toxicity from the recreational use of 1-benzylpiperazine

AIM

This study describes the demographics and symptoms of patients, who presented to the Emergency Department (ED) in Christchurch, New Zealand, with toxicity from 1-benzylpiperazine (BZP)-based "party pills." BZP use has become widespread among the 16- to 30-year age group in New Zealand. This study explores the relationship between plasma BZP level and adverse effects experienced by users. The influence of ethanol co-ingestion was also studied.

METHODS

From 1 April 2005 to 1 July 2007, all BZP-related presentations to the ED were captured on a prospective data sheet. Patients were recruited to obtain plasma BZP levels, and these were correlated with the incidence of seizures and other symptoms. Coexistent ethanol use was also correlated with the frequency of seizures and other common BZP-induced symptoms.

RESULTS

In total 178 presentations with BZP toxicity were recorded. BZP levels were measured in 96. Sixty-nine percent of patients co-ingested other substances, with the most common substance being ethanol. In patients who ingested BZP alone, increased plasma BZP levels were associated with increased seizure frequency. Ethanol co-ingestion reduced the incidence of seizures, but significantly increased the likelihood of confusion and agitation.

CONCLUSIONS

Adverse effects from BZP commonly include confusion, agitation, vomiting, anxiety, and palpitations. There is strong evidence that higher plasma levels of BZP are associated with an increased incidence of seizures. Co-ingestion of ethanol increases the likelihood of common and distressing BZP-induced symptoms but reduces the incidence of BZP seizures.

Benzylpiperazine: a drug of abuse?

N-benzylpiperazine (BZP) is the active ingredient in recreational 'party' or 'p.e.p.' pills, which are used to provide a stimulant, euphoric effect akin to that of methylenedioxymethamphetamine (MDMA, 'ecstasy'). BZP predominantly affects dopamine neurotransmission in a similar fashion to known 'drugs of abuse', such as methamphetamine and cocaine, which strongly suggests BZP has abuse liability. BZP is illegal in many countries including the United States of America and Australia, yet it remains legal in the United Kingdom, Canada and New Zealand. There has been little research, to date, on the neurological consequences of high dose or chronic exposure of BZP. Here we provide a comprehensive review of the information currently available on BZP and suggest a need for further research into the mechanisms of action, long-term effects and potentially addictive properties of BZP.

Screening for and validated quantification of amphetamines and of amphetamine- and piperazine-derived designer drugs in human blood plasma by gas chromatography/mass spectrometry

The classical stimulants amphetamine, methamphetamine, ethylamphetamine and the amphetamine-derived designer drugs MDA, MDMA ('ecstasy'), MDEA, BDB and MBDB have been widely abused for a relatively long time. In recent years, a number of newer designer drugs have entered the illicit drug market. 4-Methylthioamphetamine (MTA), p-methoxyamphetamine (PMA) and p-methoxymethamphetamine (PMMA) are also derived from amphetamine. Other designer drugs are derived from piperazine, such as benzylpiperazine (BZP), methylenedioxybenzylpiperazine (MDBP), trifluoromethylphenylpiperazine (TFMPP), m-chlorophenylpiperazine (mCPP) and p-methoxyphenylpiperazine (MeOPP). A number of severe or even fatal intoxications involving these newer substances, especially PMA, have been reported. This paper describes a method for screening for and simultaneous quantification of the above-mentioned compounds and the metabolites p-hydroxyamphetamine and p-hydroxymethamphetamine (pholedrine) in human blood plasma. The analytes were analyzed by gas chromatography/mass spectrometry in the selected-ion monitoring mode after mixed-mode solid-phase extraction (HCX) and derivatization with heptafluorobutyric anhydride. The method was fully validated according to international guidelines. It was linear from 5 to 1000 micro g l(-1) for all analytes. Data for accuracy and precision were within required limits with the exception of those for MDBP. The limit of quantification was 5 micro g l(-1) for all analytes. The applicability of the assay was proven by analysis of authentic plasma samples and of a certified reference sample. This procedure should also be suitable for confirmation of immunoassay results positive for amphetamines and/or designer drugs of the ecstasy type.

Studies on the metabolism and toxicological detection of the new designer drug N-benzylpiperazine in urine using gas chromatography-mass spectrometry

Studies are described on the metabolism and on the toxicological analysis of the piperazine-like designer drug N-benzylpiperazine (BZP, scene name "A2") in rat and human urine using gas chromatography-mass spectrometry (GC-MS). The identified metabolites indicated that BZP was hydroxylated at the aromatic ring and that the piperazine moiety is metabolically degraded. Our systematic toxicological analysis (STA) procedure using full-scan GC-MS after acid hydrolysis, liquid-liquid extraction and microwave-assisted acetylation allowed the detection of the parent compound as well as of the above mentioned metabolites in rat urine after single administration of a dose calculated from the doses commonly taken by drug users. It has also proved to be applicable in authentic clinical or forensic cases. However, it should be considered that BZP is also a metabolite of the medicament piberaline.