MDMA, methamphetamine, and CYP2D6 pharmacogenetics: what is clinically relevant?

Toxicokinetics and analytical toxicology of the phenmetrazine-derived new psychoactive substance 3,4-methylenedioxyphenmetrazine studied by means of in vitro systems

Compounds derived from known drugs are usually brought on the new psychoactive substance (NPS) market without any previous toxicological risk assessment. The European Union Drugs Agency issued an EU early notification for 3,4-methylenedioxyphenmetrazine (MDPM) in 2024. It is structurally related to the stimulants amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), and phenmetrazine and expected to have similar effects. So far, no scientific reports are available describing its toxicokinetic and analytical profile. This study aimed to provide such data to allow a thorough risk assessment and to ease its analytical detectability in forensic and clinical toxicology and doping control. Data reported include the in vitro plasma protein binding, the in vitro half-life and in vitro metabolism of MDPM by human liver microsomes and S9 fraction (pHLS9) and by HepaRG cells. A monooxygenase mapping and the in vitro cytochrome P450 inhibition of MDPM was elucidated. Results showed that HepaRG cells and pHLS9 formed the same MDPM metabolites via demethylenation and O-methylation and that MDPM has a low plasma protein binding and is a low-turnover drug. Monooxygenase mapping revealed that the demethylenation was exclusively CYP2D6-mediated. MDPM showed strong inhibition of CYP2D6 and moderate inhibition of CYP1A2 and CYP3A4. Polymorphisms or the simultaneous intake of substances that are also CYP2D6 substrates can have a considerable impact on the toxicity of MDPM. Based on in vitro data, the demethylenyl-methyl metabolite of MDPM and the parent compound are recommended as analytical urine screening targets.

A Mechanistic Review on Toxicity Effects of Methamphetamine

Persistent methamphetamine use causes many toxic effects in various organs, including the brain, heart, liver, kidney and eyes. The extent of its toxicity depends on numerous pharmacological factors, including route of administration, dose, genetic polymorphism related to drug metabolism and polysubstance abuse. Several molecular pathways have been proposed to activate oxidative stress, inflammation and apoptosis: B-cell lymphoma protein 2 (Bcl-2)-associated X (Bax)/Bcl2/caspase-3, nuclear factor erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1), protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/p70S6K, trace amine-associated receptor 1 (TAAR1)/cAMP/lysyl oxidase, Sigmar1/ cAMP response element-binding protein (CREB)/mitochondrial fission-1 protein (Fis1), NADPH-Oxidase-2 (NOX-2), renal autophagy pathway, vascular endothelial growth factor (VEGF)/phosphatidylinositol-3-kinase (PI3K)/ protein kinase B (Akt)/endothelial nitric oxide synthase (eNOS), Nupr1/Chop/P53/PUMA/Beclin1 and Toll-like receptor (TLR)4/MyD88/TRAF6 pathways. The activation promotes pathological changes, including the disruption of the blood-brain barrier, myocardial infarction, cardiomyopathy, acute liver failure, acute kidney injury, chronic kidney disease, keratitis, retinopathy and vision loss. This review revisits the pharmacological profiles of methamphetamine and its effects on the brain, heart, liver, eyes, kidneys and endothelium. Understanding the mechanisms of methamphetamine toxicity is essential in developing treatment strategies to reverse or attenuate the progress of methamphetamine-associated organ damage.

Post mortem chiral analysis of MDMA and MDA in human blood and hair

Drug-related fatalities in the EU are predominantly associated with opioids. MDMA (Ecstasy) consumption results in fewer lethal intoxications despite its widespread use. This study investigates MDMA-related fatalities, focusing on enantiomer ratios of MDMA and its metabolite MDA to explore the role of metabolism in fatal outcomes. MDMA induces euphoria, increased empathy, and physiological effects such as tachycardia, hypertension, and hyperthermia. Metabolism mainly involves CYP1A2 and CYP2D6, with polymorphism of the latter influencing metabolism rates. Our institute observed several MDMA-related fatalities, which prompted an investigation into the potential role of inefficient drug metabolism in these cases. A novel quantitative chiral analysis method was developed and validated for MDMA, MDA, amphetamine and methamphetamine enantiomers in human blood. Analysis of post mortem blood samples from eleven MDMA-related fatalities exhibited a wide range of concentrations and enantiomer ratios. Variability in R/S MDMA ratios, however, could be linked to the time period of metabolism. Hair analysis revealed high MDMA concentrations in all segments, irrespective of prior drug abuse anamnesis. Therefore, hair analysis may not be suitable for the assessment of past drug use in ecstasy-related fatalities. The results indicated that elevated levels of the MDMA enantiomer are correlated with longer survival times in cases of intoxication. However, there was no clear evidence for slowed MDMA metabolism as a cause of lethal intoxications. While challenges remain due to the diversity of cases, this study contributes valuable insights into ecstasy intoxications, aiding future interpretation of post mortem analysis.

Pharmacogenomics of 3,4-Methylenedioxymethamphetamine (MDMA): A Narrative Review of the Literature

3,4-Methylenedioxymethamphetamine (MDMA) is a synthetic amphetamine derivative with notable psychoactive properties and emerging therapeutic potential, particularly for treating post-traumatic stress disorders (PTSD) and substance use disorders. However, its use remains controversial due to inter-individual variability influenced by both environmental and genetic factors. In this context, pharmacogenomics could play a crucial role in guiding MDMA treatment by identifying individuals with genetic predispositions affecting their response to MDMA. Tailoring treatment plans based on individual's genetic makeup may enhance therapeutic outcomes and minimize adverse effects, leading to safer and more effective use of MDMA in clinical settings. Literature analysis reveals that the influence of genetic variants within genes encoded for enzymes involved in MDMA metabolism and/or pharmacodynamics (PD) targets have been relatively under-investigated in humans. Some studies have pointed out associations between MDMA-induced effects and polymorphisms. For example, the catechol-O-methyltransferase (COMT) Val158Met polymorphism has been associated with cognitive and cardiovascular MDMA-induced effects. Similarly, polymorphisms in the serotonin-linked promoter region (5HTTLPR) have been associated with several MDMA-induced adverse effects including mood disorders. However, despite these findings, only a few associations have been highlighted. Furthermore, some genes encoded for MDMA targets have been only poorly investigated, representing a significant research gap. These observations underscore the need for large-scale, controlled pharmacogenomics studies focusing on a broad panel of genes involved into MDMA pharmacokinetics and PD. Such studies could provide critical insights for optimizing MDMA's therapeutic use and minimizing its risks.

The entactogen 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) as a treatment aid in psychotherapy and its safety concerns

The phenylethylamine, 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy'), is the prototypical example of an entactogen. Its original placement in highly restrictive drug usage categories in the US and UK, led to an inevitable restriction on MDMA neuroscience research and treatment. The dominant pharmacological effects of MDMA are its properties of release and inhibition of reuptake of amine neurotransmitter transporters for dopamine, norepinephrine, and serotonin. MDMA is an agonist of a wide range of receptors; its mood-altering effects are mediated via 5-HT2A receptors; this receptor may also mediate its effects on body temperature, analgesia, and anxiolytic properties. The mechanisms underlying MDMA's entactogenic properties of sociability and interpersonal closeness are not known but release and involvement of oxytocin, a peptide thought by some to be involved in social bonding, has been suggested. Adverse effects of MDMA are mostly transient; acute multiorgan adverse effects occurring during raves or crowded dance gatherings include dehydration, hyperthermia, seizures, rhabdomyolysis, disseminated intravascular coagulation, and acute renal failure. Deaths following MDMA taken by itself are rare compared to fatalities following coadministration with other drugs. A recent FDA-approved phase 3 clinical trial of MDMA for post-traumatic stress disorder (PTSD) led to the conclusion that MDMA-assisted therapy represents a potential breakthrough treatment meriting expedited clinical evaluation. Despite the ongoing deliberations by the FDA and EMA for approval of MDMA treatment of PTSD, the Australian Therapeutic Goods Administration (TGA) recently announced that after an evaluation of the therapeutic value, benefits, and risks of MDMA, it will permit its prescribing for the treatment of PTSD. Further examples of regulatory relaxation toward MDMA-assisted psychotherapy are underway. These include the FDA's recently approved clinical trial to assess MDMA's efficacy in the treatment of "asociality" in patients with schizophrenia and an open trial of MDMA treatment for alcohol-use disorder which showed decreased alcohol consumption. There are also ongoing studies on the little understood startle response, anxiety associated with life-threatening illness, and social anxiety in autistic adults.

Hepatic injury and hepatic failure adverse events in 3,4-methylenedioxymethamphetamine users reported to the FDA Adverse Event Reporting System

3,4-Methylenedioxymethamphetamine (MDMA) is being investigated in controlled clinical trials for use as an adjunct medication treatment for post-traumatic stress disorder. MDMA is metabolized by N-demethylation, primarily by CYP2D6, to its main inactive metabolite, 4-hydroxy-3-methoxymethamphetamine. It is also metabolized to a lesser extent by CYP1A2, CYP2B6, and CYP3A4 to its active metabolite, 3,4-methylenedioxyamphetamine. Considering the extensive hepatic metabolism and excretion, MDMA use in psychiatry raises concerns over drug-induced liver injury (DILI), a rare but dangerous event. Majority of the drugs withdrawn from the market for liver injury caused death or transplantation at frequencies under 0.01%. Unfortunately, markers for liver injury were not measured in most published clinical trials. At the same time, no visible DILI-related symptoms and adverse events were observed. Idiosyncratic DILI cases are rarely registered during clinical trials due to their rare nature. In this study, we surveyed a larger, over 1,500, and a more diverse set of reports from the FDA Adverse Event Reporting System and found 23 cases of hepatic injury and hepatic failure, in which MDMA was reported to be taken in addition to one or more substances. Interestingly, 22 out of 23 cases had one or more listed drugs with a known DILI concern based on the FDA's DILIrank dataset. Furthermore, only one report had MDMA listed as the primary suspect. Considering the nearly 20 million doses of MDMA used annually, this single report is insufficient for establishing a significant association with DILI.

Recreational MDMA doses do not elicit hepatotoxicity in HepG2 spheroids under normo- and hyperthermia

MDMA (3,4-methylenedioxymethamphetamine), an entactogen with empathogenic and prosocial effects, is widely used in music festivals and other festive settings. High MDMA doses have been associated with drug-induced liver injury and cases of hyperthermia. Although the latter condition is thought to increase MDMA hepatotoxicity, this correlation remains poorly explored for recreational MDMA doses. On the other hand, the fact that MDMA acts to extinguish fear and to reconsolidate memory could be explored as an adjunct to psychotherapy during treatment of neuropsychiatric disorders such as post-traumatic stress disorder. In this context, assessing MDMA toxicity is relevant, and tridimensional cell culture has emerged as an alternative to animal models in toxicity assessment. Herein, we have used HepG2 spheroids to evaluate MDMA-induced hepatotoxicity at recreational doses, under normo- or hyperthermia. The MTT reduction assay did not evidence significantly reduced cell viability. Moreover, MDMA did not increase reactive oxygen species production, deplete the mitochondrial membrane potential, arrest the cell cycle, or induce apoptotic cell death. These findings support further pre-clinical investigation of MDMA safety from the perspective of both harm reduction and therapy given that non-abusive recreational and therapeutic doses overlap.

Acute effects of MDMA and LSD co-administration in a double-blind placebo-controlled study in healthy participants

There is renewed interest in the use of lysergic acid diethylamide (LSD) in psychiatric research and practice. Although acute subjective effects of LSD are mostly positive, negative subjective effects, including anxiety, may occur. The induction of overall positive acute subjective effects is desired in psychedelic-assisted therapy because positive acute experiences are associated with greater therapeutic long-term benefits. 3,4-Methylenedioxymethamphetamine (MDMA) produces marked positive subjective effects and is used recreationally with LSD, known as "candyflipping." The present study investigated whether the co-administration of MDMA can be used to augment acute subjective effects of LSD. We used a double-blind, randomized, placebo-controlled, crossover design with 24 healthy subjects (12 women, 12 men) to compare the co-administration of MDMA (100 mg) and LSD (100 µg) with MDMA and LSD administration alone and placebo. Outcome measures included subjective, autonomic, and endocrine effects and pharmacokinetics. MDMA co-administration with LSD did not change the quality of acute subjective effects compared with LSD alone. However, acute subjective effects lasted longer after LSD + MDMA co-administration compared with LSD and MDMA alone, consistent with higher plasma concentrations of LSD (Cmax and area under the curve) and a longer plasma elimination half-life of LSD when MDMA was co-administered. The LSD + MDMA combination increased blood pressure, heart rate, and pupil size more than LSD alone. Both MDMA alone and the LSD + MDMA combination increased oxytocin levels more than LSD alone. Overall, the co-administration of MDMA (100 mg) did not improve acute effects or the safety profile of LSD (100 µg). The combined use of MDMA and LSD is unlikely to provide relevant benefits over LSD alone in psychedelic-assisted therapy. Trial registration: ClinicalTrials.gov identifier: NCT04516902.

Diabetic Myonecrosis of the Axilla: A Novel Case With Severe Clinical Features

Diabetic myonecrosis is a rare and poorly understood complication of long-standing, inadequately controlled diabetes mellitus. Theoretical mechanisms contributing to the pathophysiology of diabetic myonecrosis include microvascular complications due to advanced glycation end-products, ischemia-reperfusion injuries, and dysregulated coagulation-fibrinolysis activity. Case reports of diabetic myonecrosis most commonly describe diabetic patients with chronically poor glycemic control who experience isolated swelling and severe pain in a unilateral lower limb with no signs of infection or systemic toxicity. Due to the rarity of this condition, there are currently no treatment guidelines. This case describes a 58-year-old male with a history of uncontrolled diabetes who presented with diabetic ketoacidosis with mixed hypovolemic and septic shock. Diabetic myonecrosis was incidentally discovered in the patient's right latissimus dorsi with CT imaging and subsequent surgical exploration. Spontaneous diabetic myonecrosis may mimic several other serious conditions and elicit suboptimal management strategies, particularly in the context of atypical presentations.

Concomitant medications associated with ischemic, hypertensive, and arrhythmic events in MDMA users in FDA adverse event reporting system

3,4-Methylenedioxymethamphetamine (MDMA) is currently being investigated as an adjunctive treatment to therapy for posttraumatic stress and other anxiety related disorders in clinical trials. Within the next few years MDMA-assisted therapy is projected for approval by regulatory authorities. MDMA's primary mechanism of action includes modulation of monoamine signaling by increasing release and inhibiting reuptake of serotonin, norepinephrine, and, to a lesser extent, dopamine. This pharmacology affects sympathomimetic physiology. In controlled trials, special attention has been given to cardiovascular adverse events (AEs), because transient increases in heart rate and blood pressure have been observed during the MDMA-assisted therapy sessions. Finding and quantifying the potential drivers of cardiac AEs in clinical trials is difficult since only a relatively small number of participants have been included in these studies, and a limited set of allowed concomitant drugs has been studied. In this study a more diverse set of reports from the FDA Adverse Event Reporting System was surveyed. We found 17 cases of cardiovascular AEs, in which the individuals had taken one or more substances in addition to MDMA. Interestingly, all of those concomitant medications and illicit substances, including opioids, stimulants, anticholinergics, and amphetamines, had been previously associated with cardiovascular AEs. Furthermore, in none of the reports MDMA was marked as the primary suspect.

Caloric state modulates locomotion, heart rate and motor neuron responses to acute administration of d-amphetamine in zebrafish larvae

Psychostimulant drugs increase behavioral, cardiac and brain responses in humans and other animals. Acute food deprivation or chronic food restriction potentiates the stimulatory effects of abused drugs and increases the propensity for relapse to drug seeking in drug-experienced animals. The mechanisms by which hunger affects cardiac and behavioral activities are only beginning to be elucidated. Moreover, changes in motor neuron activities at the single neuron level induced by psychostimulants, and their modulation by food restriction, remain unknown. Here we investigated how food deprivation affects responses to d-amphetamine by measuring locomotor activity, cardiac output, and individual motor neuron activity in zebrafish larvae. We used wild-type larval zebrafish to record behavioral and cardiac responses and the larvae of Tg(mnx1:GCaMP5) transgenic zebrafish to record motor neuron responses. Physiological state gated responses to d-amphetamine. That is, d-amphetamine evoked significant increases in motor behavior (swimming distances), heart rate and motor neuron firing frequency in food-deprived but not fed zebrafish larvae. The results extend the finding that signals arising from food deprivation are a key potentiator of the drug responses induced by d-amphetamine to the zebrafish model. The larval zebrafish is an ideal model to further elucidate this interaction and identify key neuronal substrates that may increase vulnerability to drug reinforcement, drug-seeking and relapse.

Rumors of Psychedelics, Psychotropics and Related Derivatives in Vachellia and Senegalia in Contrast with Verified Records in Australian Acacia

There are almost 1000 species of Acacia sensu stricto in Australia, while the 44 species and 4 subspecies in southern Africa were taxonomically revised in the year 2011 to Senegalia and Vachellia. There are rumors of a chemical similarity between the Australian Acacia and their southern African sister genera. Chemical analysis has unequivocally demonstrated the presence of tryptamines (i.e., DMT), β-carbolines, histamines, and phenethylamines in Australian species. However, reliable published data were not found in support of similar alkaloids in southern African (or even African) species, indicating the need for exploratory phytochemical analysis. Interestingly, the Australian species are more like the Vachellia and Senegalia from the Americas. While many reliable chemical studies have been found, there are several more that report only tentative results. Tentative data and anecdotal accounts are included in the current review to guide researchers to areas where further work can be done. For example, the current review encourages further phytochemical work to confirm if the two metabolite families, tryptamine and β-carboline alkaloids, occur together in a single specimen. Tryptamines and β-carbolines are the prerequisite ingredients of the South American psychotropic drink ayahuasca, which utilizes two different species to create this synergistic combination. These observations and others are discussed in light of geochemical variability, the potential ethnobotanical implications, and the need for further research to confirm or nullify anecdotal reports and tentative chromatographic/spectroscopic data in southern African species.

A Case of Amphetamine and Methamphetamine Intoxication in Cat

Stimulants belonging to the amphetamine group nowadays pose an undeniable worldwide threat to the life and health of users. Intoxications of domestic animals also occur, which can either be accidental or related to intentional human action. This study presents the first ever reported case of a simultaneous amphetamine and methamphetamine intoxication of a cat, along with the results of toxicological studies. Blood, urine, vitreous humor and liver were collected during the cat's autopsy and analyzed by UHPLC─QqQ─MS/MS. The sample preparation technique was based on one-step precipitation of proteins with cold acetonitrile. The determined amphetamine concentrations in the collected biological materials were 93.4 ng/mL in blood, 496.6 ng/mL in urine, 589.2 ng/mL in the vitreous humor and 291.2 ng/g in liver, respectively. Methamphetamine concentrations were 45.5 ng/mL in blood, 263.1 ng/mL in urine, 351.2 ng/mL in vitreous humor, and 97.7 ng/g in liver. Other substances were also found in the biological material, i.e., diazepam, oxazepam and nordiazepam. Cases of intentional or accidental poisoning of pets with psychoactive substances are a serious problem, carrying the risk to the health and life of the animal. Therefore, it is important to increase awareness of the high risk of poisoning of domestic animals, as well as to learn about the incompletely understood mechanisms of pharmacokinetics of various drugs in animals, including cats.

Important Drug-Drug Interactions for the Addiction Psychiatrist

The misuse of illicit substances, prescribed medications, and alcohol poses obvious health risks to afflicted individuals. When addressing these health risks, the overarching concerns generally relate to the direct effects that various substances can have on the functioning of multiple organ systems: cardiac, pulmonary, central nervous system, and others. What is not always evident, but potentially equally or even more dire, are the risks arising from drug-drug interactions involving illicit drugs and alcohol, whether with each other, or with prescribed medications. This review provides some basics that enable the reader to fruitfully approach the broad topic of drug-drug interactions.

Graphene-Based Electrochemical Sensors for Psychoactive Drugs

Sensors developed from nanomaterials are increasingly used in a variety of fields, from simple wearable or medical sensors to be used at home to monitor health, to more complicated sensors being used by border customs or aviation industries. In recent times, nanoparticle-based sensors have begun to revolutionize drug-detection techniques, mainly due to their affordability, ease of use and portability, compared to conventional chromatography techniques. Thin graphene layers provide a significantly high surface to weight ratio compared to other nanomaterials, a characteristic that has led to the design of more sensitive and reliable sensors. The exceptional properties of graphene coupled with its potential to be tuned to target specific molecules have made graphene-based sensors one of the most popular and well-researched sensing materials of the past two decades with applications in environmental monitoring, medical diagnostics, and industries. Here, we present a review of developments in the applications of graphene-based sensors in sensing drugs such as cocaine, morphine, methamphetamine, ketamine, tramadol and so forth in the past decade. We compare graphene sensors with other sensors developed from ultrathin two-dimensional materials, such as transition-metal dichalcogenides, hexagonal boron nitrate, and MXenes, to measure drugs directly and indirectly, in various samples.

Pharmacological characterization of 3,4-methylenedioxyamphetamine (MDA) analogs and two amphetamine-based compounds: N,α-DEPEA and DPIA

3,4-methylenedioxyamphetamine (MDA) is a psychoactive compound chemically related to the entactogen MDMA. MDA shares some of the entactogenic effects of MDMA but also exerts stimulant effects and psychedelic properties at higher doses. Here, we examined the pharmacological properties of MDA analogs and related amphetamine-based compounds detected in street drug samples or in sport supplements. We examined the key pharmacological mechanisms including monoamine uptake inhibition and release using human embryonic kidney 293 cells stably transfected with the respective human transporters. Additionally, we assessed monoamine transporter and receptor binding and activation properties. MDA, its fluorinated analogs, as well as the α-ethyl containing BDB and the dimeric amphetamine DPIA inhibited NET with the greatest potency and preferentially inhibited 5-HT vs. dopamine uptake. The β‑methoxy MDA analog 3C-BOH and the amphetamine-based N,α-DEPEA inhibited NET and preferentially inhibited dopamine vs. 5-HT uptake. The test drugs mediated efflux of at least one monoamine with the exception of DPIA. Most compounds bound to 5-HT_2A and 5-HT_2C receptors (K_i ≤ 10 µM) and several substances activated the 5-HT_2A and 5-HT_2B receptor as partial or full agonists. Furthermore, several compounds interacted with adrenergic receptors and the trace amine-associated receptor 1 (TAAR1) in the micromolar range. The pharmacological profiles of some fluorinated and nonfluorinated MDA analogs resemble the profile of MDMA. In contrast, 3C-BOH and N,α-DEPEA displayed more pronounced dopaminergic activity similar to amphetamine. Pharmacokinetics and pharmacodynamics studies are necessary to better establish the risks and therapeutic potential of the tested drugs.

Evidence for Gender Differences in the Amphetamine/Methamphetamine Ratio in the Hair of Subjects undergoing Fitness-to-Drive Testing

BACKGROUND AND AIMS

Retrospective analysis of hair testing data provides insights in drugs abuse patterns and improves results interpretation. Cases from subjects undergoing driving fitness assessment (2010-2020) were examined to evidence patterns in methamphetamine (MA) abuse.

MATERIALS AND METHODS

All cases with positive MA (≥0.025 ng/mg) were included (n=585). Data available were gender, age, MA and A (amphetamine) in hair (h), hair color/treatment, length of proximal hair. Cases with Ah/MAh≤0.35 (n=469) were arbitrarily selected to remove as many combined A, MA users. ANOVA was performed to detect Ah/MAh predictors.

RESULTS

No predictors affected Ah/MAh. A bimodal frequency distribution was observed. We clustered cases in two groups (1, Ah/MAh 0.025-0.070; 2, Ah/MAh 0.071-0.120) and performed logistic regression. Only gender exhibited significant difference across groups (p=0.0080). Odds ratio for females falling into group 2 was 2.86 times higher (CI97.5 1.34-6.44).

CONCLUSION

Literature data support the hypothesis that the two Ah/MAh groups represent different phenotypes of the CYP2D6-mediated MA N-demethylation. Whether gender plays a role in such difference could not be confirmed. However, these results provide further suggestion of an association of gender and pharmacogenomics with MA disposition, requiring these factors to be considered in future research.

Radiation Effects on Methamphetamine Pharmacokinetics and Pharmacodynamics in Rats

BACKGROUND AND OBJECTIVES

Whole-body radiation exposure has been shown to alter the pharmacokinetics of certain drugs in both animal models and humans, but little is known about the effect of radiation on psychoactive medications. These drugs may have altered pharmacokinetics when administered during or after space travel or therapeutic or accidental radiation exposure, resulting in reduced efficacy or increased toxicity.

METHODS

Methamphetamine was used to determine the effects of acutely administered 1, 3, and 6 Gy radiation on drug pharmacokinetics and pharmacodynamics. Male Wistar rats were exposed to 0, 1, 3, or 6 Gy X-ray radiation on day 0. The serum pharmacokinetics of subcutaneously administered 1 mg/kg methamphetamine was determined on day 3. Methamphetamine-induced (1 mg/kg) locomotor activity was measured on day 5. Brain methamphetamine concentrations were determined 2 h after methamphetamine administration (1 mg/kg) on day 6. Renal and hepatic serum biomarkers were assessed on days 3 and 6, with liver histology performed on day 6.

RESULTS

While serum half-life and unchanged methamphetamine urine clearance were unaffected by any radiation dose, maximum methamphetamine concentrations and methamphetamine and amphetamine metabolite area under the serum concentration-time curve values from 0 to 300 min were significantly reduced after 6 Gy radiation exposure. Additionally, methamphetamine-induced locomotor activity and the brain to serum methamphetamine concentration ratio were significantly elevated after 6 Gy radiation.

CONCLUSIONS

While 1-6 Gy radiation exposure did not affect methamphetamine elimination, 6 Gy exposure had effects on both subcutaneous absorption and brain distribution. These effects should be considered when administering drugs during or after radiation exposure.

Methamphetamine Dysregulation of the Central Nervous System and Peripheral Immunity

Methamphetamine (METH) is a potent psychostimulant that increases extracellular monoamines, such as dopamine and norepinephrine, and affects multiple tissue and cell types in the central nervous system (CNS) and peripheral immune cells. The reinforcing properties of METH underlie its significant abuse potential and dysregulation of peripheral immunity and central nervous system functions. Together, the constellation of METH's effects on cellular targets and regulatory processes has led to immune suppression and neurodegeneration in METH addicts and animal models of METH exposure. Here we extensively review many of the cell types and mechanisms of METH-induced dysregulation of the central nervous and peripheral immune systems. SIGNIFICANCE STATEMENT: Emerging research has begun to show that methamphetamine regulates dopaminergic neuronal activity. In addition, METH affects non-neuronal brain cells, such as microglia and astrocytes, and immunological cells of the periphery. Concurrent disruption of bidirectional communication between dopaminergic neurons and glia in the CNS and peripheral immune cell dysregulation gives rise to a constellation of dysfunctional neuronal, cell, and tissue types. Therefore, understanding the pathophysiology of METH requires consideration of the multiple targets at the interface between basic and clinical neuroscience.

4-Fluoromethamphetamine (4-FMA) induces in vitro hepatotoxicity mediated by CYP2E1, CYP2D6, and CYP3A4 metabolism

4-Fluoromethamphetamine (4-FMA) is an amphetamine-like psychoactive substance with recognized entactogenic and stimulant effects, but hitherto unclear toxicological mechanisms. Taking into consideration that the vast majority of 4-FMA users consume this substance through oral route, the liver is expected to be highly exposed. The aim of this work was to determine the hepatotoxic potential of 4-FMA using in vitro hepatocellular models: primary rat hepatocytes (PRH), human hepatoma cell lines HepaRG and HepG2, and resorting to concentrations ranging from 37 μM to 30 mM, during a 24-h exposure. EC50 values, estimated from the MTT viability assay data, were 2.21 mM, 5.59 mM and 9.57 mM, for each model, respectively. The most sensitive model, PRH, was then co-exposed to 4-FMA and cytochrome P450 (CYP) inhibitors to investigate the influence of metabolism on the toxicity of 4-FMA. Results show that CYP2E1, CYP3A4 and CYP2D6 have major roles in 4-FMA cytotoxicity. Inhibition of CYP2D6 and CYP3A4 led to left-geared shifts in the concentration-response curves of 4-FMA, hinting at a role of these metabolic enzymes for detoxifying 4-FMA, while CYP2E1 inhibition pointed towards a toxifying role of this enzyme in 4-FMA metabolism at physiologically-relevant concentrations. The drug also destabilised mitochondrial membrane potential and decreased ATP levels, increased the production of reactive oxygen and nitrogen species and compromised thiol antioxidant defences. 4-FMA further affected PRH integrity by interfering with the machinery of apoptosis and necrosis, increasing the activity of initiator and effector caspases, and causing loss of cell membrane integrity. Potential for autophagy was also observed. This research contributes to the growing body of evidence regarding the toxicity of new psychoactive substances, in particular regarding their hepatotoxic effects; the apparent influence of metabolism over the resulting cytotoxicity of 4-FMA shows that there is a substantial degree of unpredictability of the consequences for users that could be independent of the dose.

Investigation of MDMA Inhibitory Effect on CytochromeP450 3A4 in Isolated Perfused Rat Liver Model Using Tramadol

Purpose: MDMA (methylenedioxymethamphetamine) is a synthetic compound, which is a structurally derivative of amphetamine. Also, it acts like an amphetamine, structurally, and functionally. MDMA uses mechanism-based inhibition, to inhibit isoenzyme CYP2D6. It can also inhibit other isoenzymes contributing to its metabolism, including CYP3A4 which is the most important member of the cytochrome P450 superfamily. Since more than 50% of drugs are metabolized by CYP3A4, its inhibition may cause harmful and even lethal drug interactions. Tramadol, as an opioid-like analgesic, is mainly metabolized into O-desmethyl tramadol (M1), by CYP2D6 and undergoes N-demethylation to M2, by CYP2B6 and CYP3A4. Due to the significant potential of abusing tramadol, either alone or in combination with MDMA, the rate of its toxicity and side effects may increase following possible MDMA relevant enzyme inhibition.

Methods: Different doses of MDMA (1-10 mg/kg) were intraperitoneally administered to Wistar male rats of both control and treatment groups. Then, after one hour, their isolated livers were perfused by perfusion buffer containing tramadol (1 µg/mL). Afterward, perfusate samples were collected. They were analyzed by HPLC to determine the concentrations of tramadol and its metabolites.

Results: MDMA administration in treatment groups reduced M1 production. On the other hand, by following the treatment with different MDMA doses, the M2 metabolic ratio increased by 46 to 101%.

Conclusion: it seems that the regular doses of MDMA cannot inhibit the CYP3A4 activity.

Prediction of MDMA response in healthy humans: a pooled analysis of placebo-controlled studies

BACKGROUND

3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") is used both recreationally and therapeutically. Little is known about the factors influencing inter- and intra-individual differences in the acute response to MDMA. Effects of other psychoactive substances have been shown to be critically influenced by personality traits and mood state before intake.

METHODS

We pooled data from 10 randomized, double-blind, placebo-controlled, cross-over studies performed in the same laboratory in 194 healthy subjects receiving doses of 75 or 125mg of MDMA. We investigated the influence of drug dose, body weight, sex, age, drug pre-experience, genetics, personality and mental state before drug intake on the acute physiological and psychological response to MDMA.

RESULTS

In univariable analyses, the MDMA plasma concentration was the strongest predictor for most outcome variables. When adjusting for dose per body weight, we found that (a) a higher activity of the enzyme CYP2D6 predicted lower MDMA plasma concentration, (b) a higher score in the personality trait "openness to experience" predicted more perceived "closeness", a stronger decrease in "general inactivation", and higher scores in the 5D-ASC (5 Dimensions of Altered States of Consciousness Questionnaire) scales "oceanic boundlessness" and "visionary restructuralization", and (c) subjects with high "neuroticism" or trait anxiety were more likely to have unpleasant and/or anxious reactions.

CONCLUSIONS

Although MDMA plasma concentration was the strongest predictor, several personality traits and mood state variables additionally explained variance in the response to MDMA. The results confirm that both pharmacological and non-pharmacological variables influence the response to MDMA. These findings may be relevant for the therapeutic use of MDMA.

Cellular Uptake of Psychostimulants - Are High- and Low-Affinity Organic Cation Transporters Drug Traffickers?

Psychostimulants are used therapeutically and for illegal recreational purposes. Many of these are inhibitors of the presynaptic noradrenaline, dopamine, and serotonin transporters (NET, DAT, and SERT). According to their physicochemical properties, some might also be substrates of polyspecific organic cation transporters (OCTs) that mediate uptake in liver and kidneys for metabolism and excretion. OCT1 is genetically highly polymorphic, with strong effects on transporter activity and expression. To study potential interindividual differences in their pharmacokinetics, 18 psychostimulants and hallucinogens were assessed in vitro for transport by different OCTs as well as by the high-affinity monoamine transporters NET, DAT, and SERT. The hallucinogenic natural compound mescaline was found to be strongly transported by wild-type OCT1 with a K_m of 24.3 µM and a v_max of 642 pmol × mg protein⁻¹ × min⁻¹. Transport was modestly reduced in variants *2 and *7, more strongly reduced in *3 and *4, and lowest in *5 and *6, while *8 showed a moderately increased transport capacity. The other phenylethylamine derivatives methamphetamine, para-methoxymethamphetamine, (-)-ephedrine, and cathine ((+)-norpseudoephedrine), as well as dimethyltryptamine, were substrates of OCT2 with K_m values in the range of 7.9–46.0 µM and v_max values between 70.7 and 570 pmol × mg protein⁻¹ × min⁻¹. Affinities were similar or modestly reduced and the transport capacities were reduced down to half in the naturally occurring variant A270S. Cathine was found to be a substrate for NET and DAT, with the K_m being 21-fold and the v_max 10-fold higher for DAT but still significantly lower compared to OCT2. This study has shown that several psychostimulants and hallucinogens are substrates for OCTs. Given the extensive cellular uptake of mescaline by the genetically highly polymorphic OCT1, strong interindividual variation in the pharmacokinetics of mescaline might be possible, which could be a reason for highly variable adverse reactions. The involvement of the polymorphic OCT2 in the renal excretion of several psychostimulants could be one reason for individual differences in toxicity.

Reported Cases of Serotonin Syndrome in MDMA Users in FAERS Database

3,4-Methylenedioxymethamphetamine (MDMA), is investigated as a treatment for post-traumatic stress disorder and other anxiety-related conditions in multiple placebo-controlled and open label studies. MDMA-assisted therapy is projected for approval by the United States Food and Drug Administration (FDA) and other regulatory agencies worldwide within the next few years. MDMA is a monoamine releaser and uptake inhibitor affecting serotonin, potentially increasing the risk of serotonin syndrome (SS). No instances of SS have occurred in clinical trials. The relatively small number of patients in controlled trials warranted a survey of FDA Adverse Event Reporting System data for the occurrence of SS in a larger database. We found 20 SS cases in people exposed to MDMA, all of which had also taken one or more substances with serotonergic properties in addition to MDMA, including amphetamines, stimulants, and opioids. There were no cases of SS associated with MDMA where MDMA was the sole reported compound taken.

CYP2J2 Molecular Recognition: A New Axis for Therapeutic Design

Cytochrome P450 (CYP) epoxygenases are a special subset of heme-containing CYP enzymes capable of performing the epoxidation of polyunsaturated fatty acids (PUFA) and the metabolism of xenobiotics. This dual functionality positions epoxygenases along a metabolic crossroad. Therefore, structure-function studies are critical for understanding their role in bioactive oxy-lipid synthesis, drug-PUFA interactions, and for designing therapeutics that directly target the epoxygenases. To better exploit CYP epoxygenases as therapeutic targets, there is a need for improved understanding of epoxygenase structure-function. Of the characterized epoxygenases, human CYP2J2 stands out as a potential target because of its role in cardiovascular physiology. In this review, the early research on the discovery and activity of epoxygenases is contextualized to more recent advances in CYP epoxygenase enzymology with respect to PUFA and drug metabolism. Additionally, this review employs CYP2J2 epoxygenase as a model system to highlight both the seminal works and recent advances in epoxygenase enzymology. Herein we cover CYP2J2's interactions with PUFAs and xenobiotics, its tissue-specific physiological roles in diseased states, and its structural features that enable epoxygenase function. Additionally, the enumeration of research on CYP2J2 identifies the future needs for the molecular characterization of CYP2J2 to enable a new axis of therapeutic design.

Effect of bile duct ligation-induced liver dysfunction on methamphetamine pharmacokinetics in male and female rats

BACKGROUND

Several disease states commonly associated with methamphetamine (METH) use produce liver dysfunction, and in the bile duct ligation (BDL) model of hepatic dysfunction, rats with liver injury are more sensitive to METH effects. Additionally, both female rats and humans are known to be more sensitive to METH than males. In consideration of known sex-dependent differences in METH pharmacokinetics, this study sought to determine the potential interaction between sex and liver dysfunction variables on METH pharmacokinetics.

METHODS

Sham or BDL surgery was performed on male and female rats on day 0. Serum biomarker and pharmacokinetics studies with 3 mg/kg subcutaneous (SC) METH were performed on day 7. METH-induced weight loss was measured on day 8. Liver histology evaluation and brain METH concentration measurements were performed on day 9.

RESULTS

While BDL surgery produced significantly elevated alanine aminotransferase and bile duct proliferation in male compared to female rats, there were no significant interactions between sex and liver function in the pharmacokinetic parameters. Both liver dysfunction and female sex, however, were associated with significantly slower METH serum clearance and significantly higher brain METH concentrations (p < .05).

CONCLUSIONS

BDL-induced hepatic dysfunction produces substantial reductions in METH clearance and increased brain METH concentrations in both male and female rats, despite less liver injury in females. This preclinical model may be useful to identify and correct potential liver dysfunction comorbidity-related problems with future pharmacotherapy for stimulant use disorder with METH prior to expensive clinical trials.

Toxicological analysis of serious drug-related harm among electronic dance music festival attendees in New South Wales, Australia: A consecutive case series

BACKGROUND

A substantial increase in drug-related harm was observed during the 2018-2019 music festival season in New South Wales, Australia, including the deaths of five young people. As part of a rapid public health response, the New South Wales Ministry of Health referred samples from patients with suspected severe drug-related illness for forensic toxicological testing to identify the type and concentration of substances associated with the presentations.

METHODS

Cases were identified through a variety of active and passive surveillance systems, and selected consecutively based on indicators of clinical severity. Comprehensive toxicology testing of blood and urine samples was expedited for all cases. Demographic and clinical characteristics were collated, together with quantitative toxicology results. Results were analysed using descriptive statistics.

RESULTS

Forty cases from eleven different music festivals were included. The majority of cases (80.0%) were aged 25 years and under. There were five fatalities, and 62.5% of cases were admitted to intensive care units. MDMA was the most frequent substance, detected in 87.5% of cases. In 82.9% of cases with MDMA, blood concentrations were above thresholds that have been associated with toxicity. Multiple substances were detected in 60.0% of cases. Novel psychoactive substances were not detected.

CONCLUSIONS

Our findings strongly suggest that MDMA-related toxicity was a major factor in the severity of the clinical presentations among these cases. Other substances may have enhanced MDMA toxicity but appear unlikely to have caused severe toxicity in isolation. These findings have important implications for harm reduction strategies targeted to music festival settings.

Sensitive imprinted optical sensor based on mesoporous structure and green nanoparticles for the detection of methamphetamine in plasma and urine

Methamphetamine (MA), a psychoactive substance with many medicinal applications in different countries, has destructive impacts on the nervous system and brain and can lead to addiction. The optimal system for MA determination must be able to measure the tiny amount of MA in complex matrixes accurately. In the current work, a simple and biocompatible sensitive optical probe was developed based on molecularly imprinted polymers (MIPs) technique and by using green CQDs and mesoporous structured imprinting microspheres (SiO₂@CQDs@ms-MIPs). CQDs (Ф_F = 33%) were synthesized via the hydrothermal method using natural chewing gum as carbon source. SiO₂ nanoparticles were used as the backup substrate for the placement of CQDs. In spite of biocompatibility, porosity and having high specific area are the unique features of SiO₂ nanoparticles. When MA is present, the fluorescence response of MIPs enhances. This is caused by the passivation and adjustment of active clusters that are present on the surface of CQDs. By this optical sensor, the favorable linear dynamic range (5.0-250 μM) and the detection limit (1.6 μM) were obtained. The applicability of the advanced sensor was studied in real samples such as human urine and human blood plasma. Acceptable results were obtained and recovery amounts were in the 92-110% interval.

Adverse pharmacokinetic interactions between illicit substances and clinical drugs

Adverse pharmacokinetic interactions between illicit substances and clinical drugs are of a significant health concern. Illicit substances are taken by healthy individuals as well as by patients with medical conditions such as mental illnesses, acquired immunodeficiency syndrome, diabetes mellitus and cancer. Many individuals that use illicit substances simultaneously take clinical drugs meant for targeted treatment. This concomitant usage can lead to life-threatening pharmacokinetic interactions between illicit substances and clinical drugs. Optimal levels and activity of drug-metabolizing enzymes and drug-transporters are crucial for metabolism and disposition of illicit substances as well as clinical drugs. However, both illicit substances and clinical drugs can induce changes in the expression and/or activity of drug-metabolizing enzymes and drug-transporters. Consequently, with concomitant usage, illicit substances can adversely influence the therapeutic outcome of coadministered clinical drugs. Likewise, clinical drugs can adversely affect the response of coadministered illicit substances. While the interactions between illicit substances and clinical drugs pose a tremendous health and financial burden, they lack a similar level of attention as drug-drug, food-drug, supplement-drug, herb-drug, disease-drug, or other substance-drug interactions such as alcohol-drug and tobacco-drug interactions. This review highlights the clinical pharmacokinetic interactions between clinical drugs and commonly used illicit substances such as cannabis, cocaine and 3, 4-Methylenedioxymethamphetamine (MDMA). Rigorous efforts are warranted to further understand the underlying mechanisms responsible for these clinical pharmacokinetic interactions. It is also critical to extend the awareness of the life-threatening adverse interactions to both health care professionals and patients.

Evaluation of drug-endangered children: The yield of toxicology and skeletal survey screening

BACKGROUND

Drug endangerment is known to be associated with child maltreatment. However, even with the high association between physical abuse and drug endangerment there is no standard for screening in this population. Skeletal survey screening may facilitate the identification of children in this population who have also been physically abused.

OBJECTIVE

Our objective was to determine the characteristics of drug endangered children and specifically the yield of skeletal survey screening.

PARTICIPANTS AND SETTING

The participants in this study were children referred by Child Protective Services (CPS) due to concerns of drug exposure. They were seen in a child abuse outpatient clinic by a child abuse pediatrician or pediatric nurse practitioner.

METHODS

This study is a retrospective chart review of the Child Advocacy Resource and Evaluation (C.A.R.E.) Team records between January 1, 2011 and December 31, 2017. We measured the yield of toxicology, additional abuse endured, and skeletal survey findings.

RESULTS

Over the 6-year period, 1252 cases were referred to C.A.R.E. Team for drug endangerment. 1150 cases had hair toxicology performed with 595 cases (52%) testing positive for at least one illegal substance. The compound most frequently identified was methamphetamine followed by marijuana and cocaine. In addition to drug endangerment, other forms of abuse were identified in 162 cases including sexual, physical, and neglect. Using the American Academy of Pediatrics (AAP) and American College of Radiology (ACR) guidelines, 340 skeletal surveys were performed. Twelve cases (4%) had occult skeletal injuries none of which had cutaneous findings. Of those with skeletal injury, 11 cases out of 11 tested by hair toxicology were positive for at least one illegal substance.

CONCLUSIONS

The application of the AAP and ACR guidelines for skeletal survey screening to those children referred for drug endangerment is useful in identifying children with physical abuse.

Metabolites of the ring-substituted stimulants MDMA, methylone and MDPV differentially affect human monoaminergic systems

BACKGROUND

Amphetamine analogs with a 3,4-methylenedioxy ring-substitution are among the most popular illicit drugs of abuse, exerting stimulant and entactogenic effects. Enzymatic N-demethylation or opening of the 3,4-methylenedioxy ring via O-demethylenation gives rise to metabolites that may be pharmacologically active. Indeed, previous studies in rats show that specific metabolites of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxymethcathinone (methylone) and 3,4-methylenedioxypyrovalerone (MDPV) can interact with monoaminergic systems.

AIM

Interactions of metabolites of MDMA, methylone and MDPV with human monoaminergic systems were assessed.

METHODS

The ability of parent drugs and their metabolites to inhibit uptake of tritiated norepinephrine, dopamine and serotonin (5-HT) was assessed in human embryonic kidney 293 cells transfected with human monoamine transporters. Binding affinities and functional activity at monoamine transporters and various receptor subtypes were also determined.

RESULTS

MDMA and methylone displayed greater potency to inhibit norepinephrine uptake as compared to their effects on dopamine and 5-HT uptake. N-demethylation of MDMA failed to alter uptake inhibition profiles, whereas N-demethylation of methylone decreased overall transporter inhibition potencies. O-demethylenation of MDMA, methylone and MDPV resulted in catechol metabolites that maintained norepinephrine and dopamine uptake inhibition potencies, but markedly reduced activity at 5-HT uptake. O-methylation of the catechol metabolites significantly decreased norepinephrine uptake inhibition, resulting in metabolites lacking significant stimulant properties.

CONCLUSIONS

Several metabolites of MDMA, methylone and MDPV interact with human transporters and receptors at pharmacologically relevant concentrations. In particular, N-demethylated metabolites of MDMA and methylone circulate in unconjugated form and could contribute to the in vivo activity of the parent compounds in human users.

No Influence of Dopamine System Gene Variations on Acute Effects of MDMA

3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a recreational substance also investigated as medication for posttraumatic stress disorder. Dopamine (DA) system stimulation likely contributes to the acute mood effects of amphetamines, including MDMA. Genetic variants, such as single-nucleotide polymorphisms (SNPs), and polymorphic regions of the DA system genes may in part explain interindividual differences in the acute responses to MDMA in humans. We characterized the effects of common genetic variants within genes coding for key players in the DA system including the dopamine D2 receptor (DRD2/ANKK1 rs1800497, DRD2 rs6277, and rs107959), the dopamine transporter (DAT1 rs28363170, rs3836790, rs6347, rs11133767, rs11564774, rs460000, and rs463379), and dopamine D4 receptor [DRD4, variable-number tandem repeat (VNTR)] on the subjective and autonomic response to MDMA (125 mg) in pooled data from randomized, placebo-controlled, crossover studies in a total of 149 healthy subjects. Plasma concentrations of MDMA were used as covariate in the analysis to control for individual pharmacokinetic (metabolic and weight) differences. None of the tested genetic polymorphisms within the DA system altered effects of MDMA when adjusting for multiple comparisons. Genetic variations in genes coding for players of the DA system are unlikely to explain interindividual variations in the acute effects of MDMA in humans.

Gender differences in the behavioral and subjective effects of methamphetamine in healthy humans

RATIONALE

Methamphetamine (MA) use is steadily increasing and thus constitutes a major public health concern. Women seem to be particularly vulnerable to developing MA use disorder, as they initiate use at a younger age and transition more quickly to problematic use. Initial drug responses may predict subsequent use, but little information exists on potential gender differences in the acute effects of MA prior to dependence.

OBJECTIVE

We examined gender differences in the acute effects of MA on subjective mood and reward-related behavior in healthy, non-dependent humans.

METHODS

Men (n = 44) and women (n = 29) completed 4 sessions in which they received placebo or MA under double-blind conditions twice each. During peak drug effect, participants completed the monetary incentive delay task to assess reaction times to cues signaling potential monetary losses or gains, in an effort to determine if MA would potentiate reward-motivated behavior. Cardiovascular and subjective drug effects were assessed throughout sessions.

RESULTS

Overall, participants responded more quickly to cues predicting incentivized trials, particularly large-magnitude incentives, than to cues predicting no incentive. MA produced faster reaction times in women, but not in men. MA produced typical stimulant-like subjective and cardiovascular effects in all participants, but subjective ratings of vigor and (reduced) sedation were greater in women than in men.

CONCLUSIONS

Women appear to be more sensitive to the psychomotor-related behavioral and subjective effects of MA. These findings provide initial insight into gender differences in acute effects of MA that may contribute to gender differences in problematic MA use.

Drug Interactions With New Synthetic Opioids

Fentanyl, fentanyl analogs, and other new synthetic opioids (NSO) have burst onto the illegal drug market as new psychoactive substances (NPS). They are often sold as heroin to unsuspecting users and produce euphoria through their agonist action on μ- opioid receptors. Their high consumption, often combined with other substances, has led to multiple intoxications during recent years. In some countries, such as the United States, the consumption of opioids, whether for medical or recreational purposes, has become epidemic and is considered a public health problem. Fentanyl analogs are more potent than fentanyl which in turn is 50 times more potent than morphine. Furthermore, some fentanyl analogs have longer duration of action and therefore interactions with other substances and medicines can be more serious. This review is focused on the potentially most frequent interactions of opioid NPS taking into account the drugs present in the reported cases of poly-intoxication, including other illegal drugs of abuse and medication. Substances involved are mainly antidepressants, antihistamines, antipsychotics, benzodiazepines, analgesics, anesthetics, psychostimulants, other opioids, alcohol, and illegal drugs of abuse. The interactions can be produced due to pharmacokinetic and pharmacodynamic mechanisms. Naloxone can be used as an antidote, although required doses might be higher than for traditional opioid intoxications. It is crucial that doctors who habitually prescribe opioids, which are often misused by patients and NPS users, be aware of designer opioids' potentially life-threatening drug-drug interactions in order to prevent new cases of intoxication.

A genetic reduction in the serotonin transporter differentially influences MDMA and heroin induced behaviours

BACKGROUND

Despite ongoing study and research to better understand drug addiction, it continues to be a heavy burden. Only a small percentage of individuals who take drugs of abuse go on to develop addiction. However, there is growing evidence to suggest that a reduction in the serotonin transporter may play an important role for those that transition to compulsive drug taking. Studies have demonstrated that reduced serotonin transporter function potentiates self-administration of psychostimulant drugs ("ecstasy," MDMA; cocaine); however, additional research revealed no differences between genotypes when the opioid heroin was self-administered. These results suggest that a reduction in the serotonin transporter may confer susceptibility to the development of addiction to some classes of drugs but not others. Importantly, the mechanism underlying facilitated psychostimulant self-administration is currently unknown.

METHODS

Therefore, to continue investigating the relationship between compromised serotonergic function and different classes of drugs, a series of experiments was conducted investigating locomotor activity (LMA) and conditioned taste aversion (CTA) in the serotonin transporter knockout (SERT KO) rat model.

RESULTS

MDMA-induced hyperactivity was reduced, while MDMA-induced CTA was enhanced, in SERT KO rats. However, there were no genotype differences in heroin-induced behaviours.

CONCLUSIONS

These results reinforce the idea that a reduction in the serotonin transporter drives differential effects between disparate classes of drugs of abuse.

Association between cytochrome P450 2D6 polymorphisms and body fluid methamphetamine concentrations in Japanese forensic autopsy cases

Methamphetamine (MA) is an illicit stimulant that affects the central nervous system. Cytochrome P450 2D6 (CYP2D6) plays an important role in MA metabolism. Numerous allelic variants confer substantial variation in CYP2D6 activity among individuals. In the present study, we examined the frequencies of CYP2D6 alleles, including CYP2D6*1, *2, *4, *5, *10, *14A, *14B, *18, and *36, and multiplication, in 82 forensic autopsy cases of MA abusers and 567 autopsy cases in which MA was not detected (controls). Ultrarapid metabolizer (UM), extensive metabolizer (EM), intermediate metabolizer (IM), and poor metabolizer (PM) phenotypes were predicted from CYP2D6 genotypes. Of MA abusers, 64 subjects were predicted to be EM, 17 were IM, and 1 was UM. No MA abuser had the predicted PM phenotype. No significant differences in CYP2D6 phenotype frequencies were found between MA abusers and controls. MA and amphetamine (AMP) concentrations were measured in the right heart blood, left heart blood, peripheral external iliac blood, urine, pericardial fluid, and bone marrow of MA abusers. MA concentrations in urine and bone marrow were significantly higher in IM than in EM. AMP concentration was not associated with CYP2D6 phenotype in any body fluid. These results suggest that the MA concentration in body fluids is influenced by CYP2D6 phenotypes in the Japanese population.

No major role of norepinephrine transporter gene variations in the cardiostimulant effects of MDMA

PURPOSE

Methylenedioxymethamphetamine (MDMA, ecstasy) is used recreationally and frequently leads to sympathomimetic toxicity. MDMA produces cardiovascular and subjective stimulant effects that were shown to partially depend on the norepinephrine transporter (NET)-mediated release of norepinephrine and stimulation of α1-adrenergic receptors. Genetic variants, such as single-nucleotide polymorphisms (SNPs), of the NET gene (SLC6A2) may explain interindividual differences in the acute stimulant-type responses to MDMA in humans.

METHODS

We characterized the effects of common genetic variants of the SLC6A2 gene (rs168924, rs47958, rs1861647, rs2242446, and rs36029) on cardiovascular and subjective stimulation after MDMA administration in 124 healthy subjects in a pooled analysis of eight double-blind, placebo-controlled studies.

RESULTS

Carriers of the GG genotype of the SLC6A2 rs1861647 SNP presented higher elevations of heart rate and rate-pressure product after MDMA than subjects with one or no G alleles. Subjects with a C allele in the SLC6A2 rs2242446 SNP presented higher elevations of the heart rate after MDMA administration compared with the TT genotype. Subjects with the AA genotype of the SLC6A2 rs36029 SNP presented higher elevations of mean arterial pressure and rate pressure product after MDMA administration than carriers of the G allele. The SLC6A2 rs168924 and rs47958 SNPs did not alter the response to MDMA.

CONCLUSIONS

Genetic polymorphisms of the SLC6A2 gene weakly moderated the acute cardiovascular response to MDMA in controlled studies and may play a minor role in adverse cardiovascular events when MDMA is used recreationally.

Drug-induced pulmonary arterial hypertension: a primer for clinicians and scientists

Drug-induced pulmonary arterial hypertension (D-PAH) is a form of World Health Organization Group 1 pulmonary hypertension (PH) defined by severe small vessel loss and obstructive vasculopathy, which leads to progressive right heart failure and death. To date, 16 different compounds have been associated with D-PAH, including anorexigens, recreational stimulants, and more recently, several Food and Drug Administration-approved medications. Although the clinical manifestation, pathology, and hemodynamic profile of D-PAH are indistinguishable from other forms of pulmonary arterial hypertension, its clinical course can be unpredictable and to some degree dependent on removal of the offending agent. Because only a subset of individuals develop D-PAH, it is probable that genetic susceptibilities play a role in the pathogenesis, but the characterization of the genetic factors responsible for these susceptibilities remains rudimentary. Besides aggressive treatment with PH-specific therapies, the major challenge in the management of D-PAH remains the early identification of compounds capable of injuring the pulmonary circulation in susceptible individuals. The implementation of pharmacovigilance, precision medicine strategies, and global warning systems will help facilitate the identification of high-risk drugs and incentivize regulatory strategies to prevent further outbreaks of D-PAH. The goal for this review is to inform clinicians and scientists of the prevalence of D-PAH and to highlight the growing number of common drugs that have been associated with the disease.

Progress and promise for the MDMA drug development program

Pharmacotherapy is often used to target symptoms of posttraumatic stress disorder (PTSD), but does not provide definitive treatment, and side effects of daily medication are often problematic. Trauma-focused psychotherapies are more likely than drug treatment to achieve PTSD remission, but have high dropout rates and ineffective for a large percentage of patients. Therefore, research into drugs that might increase the effectiveness of psychotherapy is a logical avenue of investigation. The most promising drug studied as a catalyst to psychotherapy for PTSD thus far is 3,4-methylenedioxymethamphetamine (MDMA), commonly known as the recreational drug "Ecstasy." MDMA stimulates the release of hormones and neurochemicals that affect key brain areas for emotion and memory processing. A series of recently completed phase 2 clinical trials of MDMA-assisted psychotherapy for treatment of PTSD show favorable safety outcomes and large effect sizes that warrant expansion into multi-site phase 3 trials, set to commence in 2018. The nonprofit sponsor of the MDMA drug development program, the Multidisciplinary Association for Psychedelic Studies (MAPS), is supporting these trials to explore whether MDMA, administered on only a few occasions, can increase the effectiveness of psychotherapy. Brain imaging techniques and animal models of fear extinction are elucidating neural mechanisms underlying the robust effects of MDMA on psychological processing; however, much remains to be learned about the complexities of MDMA effects as well as the complexities of PTSD itself.

Studies on Para-Methoxymethamphetamine (PMMA) Metabolite Pattern and Influence of CYP2D6 Genetics in Human Liver Microsomes and Authentic Samples from Fatal PMMA Intoxications

Para-methoxymethamphetamine (PMMA) has caused numerous fatal poisonings worldwide and appears to be more toxic than other ring-substituted amphetamines. Systemic metabolism is suggested to be important for PMMA neurotoxicity, possibly through activation of minor catechol metabolites to neurotoxic conjugates. The aim of this study was to examine the metabolism of PMMA in humans; for this purpose, we used human liver microsomes (HLMs) and blood samples from three cases of fatal PMMA intoxication. We also examined the impact of CYP2D6 genetics on PMMA metabolism by using genotyped HLMs isolated from CYP2D6 poor, population-average, and ultrarapid metabolizers. In HLMs, PMMA was metabolized mainly to 4-hydroxymethamphetamine (OH-MA), whereas low concentrations of para-methoxyamphetamine (PMA), 4-hydroxyamphetamine (OH-A), dihydroxymethamphetamine (di-OH-MA), and oxilofrine were formed. The metabolite profile in the fatal PMMA intoxications were in accordance with the HLM study, with OH-MA and PMA being the major metabolites, whereas OH-A, oxilofrine, HM-MA and HM-A were detected in low concentrations. A significant influence of CYP2D6 genetics on PMMA metabolism in HLMs was found. The catechol metabolite di-OH-MA has previously been suggested to be involved in PMMA toxicity. Our studies show that the formation of di-OH-MA from PMMA was two to seven times lower than from an equimolar dose of the less toxic drug MDMA, and do not support the hypothesis of catechol metabolites as major determinants of fatal PMMA toxicity. The present study revealed the metabolite pattern of PMMA in humans and demonstrated a great impact of CYP2D6 genetics on human PMMA metabolism.

The prognosis following amphetamine poisoning

Aims: This study investigated the long-term mortality following poisoning by amphetamine or substituted amphetamines. Furthermore, we examined the social problems and somatic and psychiatric co-morbidity related to amphetamine poisoning, and their impact on the long-term survival. Methods: We identified amphetamine poisoned patients from the Danish Poison Information Centre database and correlated their personal identification numbers with seven Danish national registries related to different social and health aspects. For each case, we sampled 100 age and gender matched controls from the background population. Results: From August 2006 to December 2013 we identified 1444 patients (70% males) who experienced amphetamine poisoning; 52% of the cases were classified as mixed poisonings and the average age at first contact was 24.8 years (SD 8.6). The prevalence of psychiatric disorders, HIV, viral hepatitis, and previous prison incarceration was approximately 10 times higher than among healthy controls. After seven years 11% were deceased as opposed to 0.6% in the control group, and 64% of the patients died from unnatural causes. Male gender (HR 2.29, 95% CI (1.07-4.90)), age (HR 1.06, 95% CI (1.03-1.09)), opioid dependence (HR 2.88, 95% CI (1.42-5.85)), schizophrenia (HR 3.09,95% CI (1.63-5.86)), affective disorders (HR 2.65, 95% CI (1.44-4.90)) and HIV (HR 5.45, 95% CI (1.19-24.90)) were associated with a high mortality. Furthermore, a significant proportion of these patients experienced social and health related deterioration in the years following poisoning. Conclusions: Amphetamine poisoning is associated with a poor long-term prognosis and is complicated by additional social and health related issues.

Reduced carboxylesterase 1 is associated with endothelial injury in methamphetamine-induced pulmonary arterial hypertension

Pulmonary arterial hypertension is a complication of methamphetamine use (METH-PAH), but the pathogenic mechanisms are unknown. Given that cytochrome P450 2D6 (CYP2D6) and carboxylesterase 1 (CES1) are involved in metabolism of METH and other amphetamine-like compounds, we postulated that loss of function variants could contribute to METH-PAH. Although no difference in CYP2D6 expression was seen by lung immunofluorescence, CES1 expression was significantly reduced in endothelium of METH-PAH microvessels. Mass spectrometry analysis showed that healthy pulmonary microvascular endothelial cells (PMVECs) have the capacity to both internalize and metabolize METH. Furthermore, whole exome sequencing data from 18 METH-PAH patients revealed that 94.4% of METH-PAH patients were heterozygous carriers of a single nucleotide variant (SNV; rs115629050) predicted to reduce CES1 activity. PMVECs transfected with this CES1 variant demonstrated significantly higher rates of METH-induced apoptosis. METH exposure results in increased formation of reactive oxygen species (ROS) and a compensatory autophagy response. Compared with healthy cells, CES1-deficient PMVECs lack a robust autophagy response despite higher ROS, which correlates with increased apoptosis. We propose that reduced CES1 expression/activity could promote development of METH-PAH by increasing PMVEC apoptosis and small vessel loss.

Multifaceted empathy of healthy volunteers after single doses of MDMA: A pooled sample of placebo-controlled studies

Previous placebo-controlled experimental studies have shown that a single dose of MDMA can increase emotional empathy in the multifaceted empathy test (MET) without affecting cognitive empathy. Although sufficiently powered to detect main effects of MDMA, these studies were generally underpowered to also validly assess contributions of additional parameters, such as sex, drug use history, trait empathy and MDMA or oxytocin plasma concentrations. The present study examined the robustness of the MDMA effect on empathy and investigated the moderating role of these additional parameters. Participants ( n = 118) from six placebo-controlled within-subject studies and two laboratories were included in the present pooled analysis. Empathy (MET), MDMA and oxytocin plasma concentrations were assessed after oral administration of MDMA (single dose, 75 or 125 mg). Trait empathy was assessed using the interpersonal reactivity index. We confirmed that MDMA increased emotional empathy at both doses without affecting cognitive empathy. This MDMA-related increase in empathy was most pronounced during presentation of positive emotions as compared with negative emotions. MDMA-induced empathy enhancement was positively related to MDMA blood concentrations measured before the test, but independent of sex, drug use history and trait empathy. Oxytocin concentrations increased after MDMA administration but were not associated with behavioral effects. The MDMA effects on emotional empathy were stable across laboratories and doses. Sex did not play a moderating role in this effect, and oxytocin levels, trait empathy and drug use history were also unrelated. Acute drug exposure was of significant relevance in the MDMA-induced emotional empathy elevation.

CYP2D6 function moderates the pharmacokinetics and pharmacodynamics of 3,4-methylene-dioxymethamphetamine in a controlled study in healthy individuals

Supplemental Digital Content is available in the text.

The role of genetic polymorphisms in cytochrome (CYP) 2D6 involved in the metabolism of 3,4-methylene-dioxymethamphetamine (MDMA, ecstasy) is unclear. Effects of genetic variants in CYP2D6 on the pharmacokinetics and pharmacodynamic effects of MDMA were characterized in 139 healthy individuals (70 men, 69 women) in a pooled analysis of eight double-blind, placebo-controlled crossover studies. In CYP2D6 poor metabolizers, the maximum concentrations (C_max) of MDMA and its active metabolite 3,4-methylene-dioxyamphetamine were +15 and +50% higher, respectively, compared with extensive metabolizers and the C_max of the inactive metabolite 4-hydroxy-3-methoxymethamphetamine was 50–70% lower. Blood pressure and subjective drug effects increased more rapidly after MDMA administration in poor metabolizers than in extensive metabolizers. In conclusion, the disposition of MDMA and its effects in humans are altered by polymorphic CYP2D6 activity, but the effects are small because of the autoinhibition of CYP2D6.

Effects of Electroacupuncture on Methamphetamine-Induced Behavioral Changes in Mice

Methamphetamine (METH) is a major drug of abuse worldwide, and no efficient therapeutic strategies for treating METH addiction are currently available. Continuous METH use can cause behavioral upregulation or psychosis. The dopaminergic pathways, particularly the neural circuitry from the ventral tegmental area to the nucleus accumbens (NAc), have a critical role in this behavioral stage. Acupuncture has been used for treating diseases in China for more than 2000 years. According to a World Health Organization report, acupuncture can be used to treat several functional disorders, including substance abuse. In addition, acupuncture is effective against opioids addiction. In this study, we used electroacupuncture (EA) for treating METH-induced behavioral changes and investigated the possible therapeutic mechanism. Results showed that EA at the unilateral Zhubin (KI9)-Taichong (LR3) significantly reduced METH-induced behavioral sensitization and conditioned place preference. In addition, both dopamine and tyrosine hydroxylase (TH) levels decreased but monoamine oxidase A (MAO-A) levels increased in the NAc of the METH-treated mice receiving EA compared with those not receiving EA. EA may be a useful nonpharmacological approach for treating METH-induced behavioral changes, probably because it reduces the METH-induced TH expression and dopamine levels and raises MAO-A expression in the NAc.