Review of the pharmacology and clinical profile of bupropion, an antidepressant and tobacco use cessation agent

Bupropion-disguised chest pain presenting in a middle-aged male: a case report and review of literature

Introduction and importance

Chest pain is one of the most prevalent complaints amongst individuals presenting in healthcare settings, encompassing a broad spectrum of etiologies. Work-up for chest pain often focuses on excluding life-threatening conditions before the consideration of atypical causes.

Case presentation

A 47-year-old male with a past medical history of tobacco use and depression presented with persistent left-sided chest pain. Vitals on arrival were notable for mild hypertension. Two consecutive high-sensitivity troponins were unremarkable. The electrocardiogram showed sinus rhythm with no ischemic changes. Due to the atypical presentation of chest pain, the patient's home medications were reviewed, and his bupropion was discontinued due to concern for medication-induced chest pain. The patient was discharged and presented 2 days for follow-up endorsing complete resolution of his chest pain.

Clinical discussion

Prior investigations have shown bupropion to be associated with chest pain, with resolution noted after discontinuation. The etiology of chest pain is likely sympathomimetic, as bupropion has been shown to exhibit positive inotropic effects on myocardial tissue, propagated by catecholamine release.

Conclusion

Patients taking bupropion may present with atypical chest pain. Medication discontinuation may be beneficial in alleviating symptoms.

Depression Severity Moderates Reward Learning Among Smokers With Current or Past Major Depressive Disorder in a Smoking Cessation Randomized Clinical Trial

INTRODUCTION

Behavioral and pharmacological smoking cessation treatments are hypothesized to increase patients' reward learning to reduce craving. Identifying changes in reward learning processes that support effective tobacco-dependence interventions among smokers who experience depression may guide patients toward efficient treatment strategies. The objective was to investigate the extent to which adult daily cigarette smokers with current or past major depressive disorder (MDD) learned to seek reward during 12 weeks of treatment combining behavioral activation and varenicline. We hypothesized that a decline in reward learning would be attenuated (least to most) in the following order: (1) behavioral activation integrated with ST (BASC) + varenicline, (2) BASC + placebo, (3) standard behavioral cessation treatment (ST) + varenicline, (4) ST + placebo.

METHODS

We ran a phase IV, placebo-controlled, randomized clinical trial with 300 participants receiving 12 weeks of one of four conditions across two urban medical centers. Depressive symptoms were measured using the Beck Depression Inventory-II (BDI). Reward learning was ascertained at weeks 1, 7, and 14 using the Probabilistic Reward Task (PRT), a laboratory task that uses an asymmetric reinforcement schedule to assess (a) learning to seek reward (response bias), (b) differentiate between stimuli, and (c) time to react to cues.

RESULTS

There was a significant interaction of BDI group × PRT response bias. Response bias declined from weeks 7 to 14 among participants with high baseline depression symptoms. The other two BDI groups showed no change in response bias.

CONCLUSIONS

Controlling for baseline depression, participants showed a decrease in response bias from weeks 1 to 14, and from weeks 7 to 14. Treatment condition and abstinence status were unassociated with change in reward learning.

IMPLICATIONS

Smokers who report greater depression severity show a decline in reward learning despite their participation in smoking cessation treatments, suggesting that depressed populations pose unique challenges with standard smoking cessation approaches.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02378714.

Allosteric modulation of serotonin and dopamine transporters: New insights from computations and experiments

Human monoamine transporters (MATs) are critical to regulating monoaminergic neurotransmission by translocating their substrates from the synaptic space back into the presynaptic neurons. As such, their primary substrate binding site S1 has been targeted by a wide range of compounds for treating neuropsychiatric and neurodegenerative disorders including depression, ADHD, neuropathic pain, and anxiety disorders. We present here a comparative study of the structural dynamics and ligand-binding properties of two MATs, dopamine transporter (DAT) and serotonin transporter (SERT), with focus on the allosteric modulation of their transport function by drugs or substrates that consistently bind a secondary site S2, proposed to serve as an allosteric site. Our systematic analysis of the conformational space and dynamics of a dataset of 50 structures resolved for DAT and SERT in the presence of one or more ligands/drugs reveals the specific residues playing a consistent role in coordinating the small molecules bound to subsites S2-I and S2-II within S2, such as R476 and Y481 in dDAT and E494, P561, and F556 in hSERT. Further analysis reveals how DAT and SERT differ in their two principal modes of structural changes, PC1 and PC2. Notably, PC1 underlies the transition between outward- and inward-facing states of the transporters as well as their gating; whereas PC2 supports the rearrangements of TM helices near the S2 site. Finally, the examination of cross-correlations between structural elements lining the respective sites S1 and S2 point to the crucial role of coupled motions between TM6a and TM10. In particular, we note the involvement of hSERT residues F335 and G338, and E493-E494-T497 belonging to these two respective helices, in establishing the allosteric communication between S1 and S2. These results help understand the molecular basis of the action of drugs that bind to the S2 site of DAT or SERT. They also provide a basis for designing allosteric modulators that may provide better control of specific interactions and cellular pathways, rather than indiscriminately inhibiting the transporter by targeting its orthosteric site.

Determination of bupropion by off-line coupling Fe3O4@CuO&GO nanocomposite and ion mobility spectrometry with application to biological samples

In this study, an off-line coupling of dispersive solid-phase extraction (DSPE) and ion mobility spectrometry (IMS) was introduced to extract and determine bupropion (BUP). A magnetic nanocomposite adsorbent (Fe3O4@CuO&GO) was fabricated by combining graphene oxide (GO) sheets with Fe3O4 and CuO through coprecipitation method. The synthesized adsorbent was characterized and analyzed using the analytical techniques. The effect of extraction parameters including desorption solvent (type and volume), pH, adsorbent amount, contact time, temperature, and the volume of analyte solution on the extraction efficiency was investigated and optimized. The operational parameters of IMS method were also investigated. Under the optimum conditions (DSPE-IMS), the proposed method provided a linear range 4.0-24.0 ng for BUP with a determination coefficient R2 ≥ 0.98. LOD and LOQ values were 0.7 and 2.2 ng for BUP. The repeatability of proposed method was evaluated and reported as relative standard deviation (RSD% ≤ 5.5). The developed method was applied to determine BUP in different biological samples, in which satisfactory results were obtained (93.0-98.0%).

Nicotine addiction and overweight affect intrinsic neural activity and neurotransmitter activity: A fMRI study of interaction effects

BACKGROUND

Nicotine addiction and overweight often co-exist, but the neurobiological mechanism of their co-morbidity remains to be clarified. In this study, we explore how nicotine addiction and overweight affect intrinsic neural activity and neurotransmitter activity.

METHODS

This study included 54 overweight people and 54 age-, sex-, and handedness-matched normal-weight individuals, who were further divided into four groups based on nicotine addiction. We used a two-way factorial design to compare intrinsic neural activity (calculated by the fALFF method) in four groups based on resting-state functional magnetic resonance images (rs-fMRI). Furthermore, the correlation between fALFF values and PET- and SPECT-derived maps to examine specific neurotransmitter system changes underlying nicotine addiction and overweight.

RESULTS

Nicotine addiction and overweight affect intrinsic neural activity by themselves. In combination, they showed antagonistic effects in the interactive brain regions (left insula and right precuneus). Cross-modal correlations displayed that intrinsic neural activity changes in the interactive brain regions were related to the noradrenaline system (NAT).

CONCLUSION

Due to the existence of interaction, nicotine partially restored the changes of spontaneous activity in the interactive brain regions of overweight people. Therefore, when studying one factor alone, the other should be used as a control variable. Besides, this work links the noradrenaline system with intrinsic neural activity in overweight nicotine addicts. By examining the interactions between nicotine addiction and overweight from neuroimaging and molecular perspectives, this study provides some ideas for the treatment of both co-morbidities.

Stereoselective Metabolism of Bupropion to Active Metabolites in Cellular Fractions of Human Liver and Intestine

Striking stereoselective disposition of the antidepressant and smoking cessation aid bupropion (BUP) and its active metabolites observed clinically influence patients' response to BUP therapy and its clinically important drug-drug interactions (DDI) with CYP2D6 substrates. However, understanding of the biochemical mechanisms responsible is incomplete. This study comprehensively examined hepatic and extrahepatic stereoselective metabolism of BUP in vitro Racemic-, R-, and S-BUP were incubated separately with pooled cellular fractions of human liver [microsomes (HLMs), S9 fractions (HLS9s), and cytosols (HLCs)] and intestinal [microsomes (HIMs), S9 fractions (HIS9s), and cytosols (HICs)] and cofactors. Formations of diastereomers of 4-hydroxyBUP (OHBUP), threohydroBUP (THBUP), and erythrohydroBUP (EHBUP) were quantified using a novel chiral ultra-high performance liquid chromatography/tandem mass spectrometry method. Racemic BUP (but not R- or S-BUP) was found suitable to determine stereoselective metabolism of BUP; both enantiomers showed complete racemization. Compared with that of RR-THBUP, the in vitro intrinsic clearance (Clint) for the formation of SS-THBUP was 42-, 19-, and 8.3-fold higher in HLMs, HLS9 fractions, and HLCs, respectively; Clint for the formation of SS-OHBUP and RS-EHBUP was also higher (2.7- to 3.9-fold) than their R-derived counterparts. In cellular fractions of human intestine, ≥ 95% of total reduction was accounted by the formation of RR-THBUP. Ours is the first to demonstrate marked stereoselective reduction of BUP in HLCs, HIMs, HIS9 fractions, and HICs, providing the first evidence for tissue- and cellular fraction-dependent stereoselective metabolism of BUP. These data may serve as the first critical step toward understanding factors dictating BUP's stereoselective disposition, effects, and DDI risks. SIGNIFICANCE STATEMENT: This work provides a deeper insight into bupropion (BUP) stereoselective oxidation and reduction to active metabolites in cellular fractions of human liver and intestine tissues. The results demonstrate tissue- and cellular fraction-dependent stereospecific metabolism of BUP. These data may improve prediction of BUP stereoselective disposition and understanding of BUP's effects and CYP2D6-dependent drug-drug interaction in vivo.

Bupropion-Induced Dystonia: A Case Report

Bupropion is one of the most commonly prescribed antidepressant medications by physicians all over the world. Because of its favorable sexual profile, it is used as an alternative to serotonin reuptake inhibitors (SSRIs). Its significance in smoking cessation is also well recognized. However, it is associated with a few side effects, such as dizziness, anxiety, tremors, nausea, and insomnia. We present the case of a 54-year-old chronic smoker who developed acute facial dystonia involving the temporomandibular joint (TMJ) after being prescribed 300 mg of bupropion. The Naranjo scale was used to assess the probability of bupropion-induced dystonia. Following the diagnosis, the drug was stopped, and the dystonia completely resolved within one week. At her follow-ups, the patient was found to have no recurrence of dystonia.

Is there a therapeutic potential in combining bupropion and naltrexone in schizophrenia?

INTRODUCTION

A sustained-release tablet composed of a combination of the dopamine and norepinephrine reuptake inhibitor bupropion (BUP) and the µ-opioid receptor antagonist naltrexone (NAT) is marketed under the brand name Contrave by Orexigen Therapeutics for appetite control. Minimal literature is available regarding the use of combination bupropion and naltrexone (BUPNAT) in individuals with schizophrenia.

AREAS COVERED

In this review, we propose a theoretical model where BUPNAT may have a therapeutic effect in the treatment of schizophrenia. We explore the pathways targeted by the constituent drugs BUP and NAT and summarize the literature on their efficacy and possible adverse effects. We then look at the potential use of BUPNAT in schizophrenia.

EXPERT OPINION

Research has hinted that BUP's dopaminergic properties affect the same striatal pathways involved in schizophrenia. NAT, via opioid receptor antagonism, indirectly increases striatal dopamine release by disinhibiting nicotinic acetylcholine receptors. As such, we hypothesize that BUPNAT can have a therapeutic effect in schizophrenia, particularly on negative symptoms. We also suggest that it may ameliorate comorbidities frequently seen in this group of patients, including obesity, smoking, and substance use. Further research and clinical data are needed to elucidate the potential clinical benefits of BUPNAT in the treatment of schizophrenia.

Isobolographic analysis of the antidepressant interaction in two-drug combinations of citalopram, bupropion, and scopolamine in mice

Depression and anxiety are psychiatric diseases that commonly occur together, and the patient burden and complexity increase when both are present. Comorbid anxiety and depression are often more resistant to common drug treatments such as antidepressants. Combination therapy is a suggested approach in treating these patients, where a decline of doses could reduce undesirable outcomes and still achieve optimal effects. We, therefore, conducted a preclinical study to assess the effect of two-drug combinations of citalopram, bupropion, and scopolamine on anxiety- and antidepressive-like behaviors in male NMRI mice and aimed to determine the nature of the interaction between components. Anxiety- or antidepressive-like activity of mice was assessed by the hole-board or forced swim test (FST), respectively. Our results revealed that citalopram (0.01-0.25 mg/kg; i.p.), bupropion (1-9 mg/kg; i.p.), or scopolamine (0.01-0.1 mg/kg; i.p.) diminished immobility time in the FST, suggesting an antidepressive-like effect. Citalopram decreased dead-dip counts in the hole-board, indicating an anxiogenic-like activity. All two-drug combinations, at inactive doses, exerted an antidepressive-like behavior. Only bupropion/scopolamine combination increased head-dip counts compared to the bupropion/saline group. Isobolographic analysis revealed an antidepressive synergy effect between citalopram plus bupropion, and an antidepressive additive impact between scopolamine plus citalopram or bupropion. It should be noted that the higher dose of each drug alone declined locomotor activity, while two-drug combinations did not affect this parameter. These results suggest a stronger antidepressive effect for citalopram/bupropion combination than other two-drug combinations.

Understanding the stimulus effects of nicotine and bupropion in a drug-drug discriminated goal-tracking task

RATIONALE

Bupropion is a non-nicotine medication for smoking cessation that has overlapping stimulus effects with nicotine as demonstrated in drug discrimination studies. Whether these shared stimulus effects will alter acquisition or maintenance of a discrimination between nicotine and bupropion is unknown.

OBJECTIVE

We sought to test this possibility using the drug discriminated goal-tracking (DGT) task and whether discrimination training history affected generalization and substitution tests.

METHODS

Sixty adult Sprague-Dawley rats (30M/30F) were equally split into three discrimination training groups: SAL-0.4NIC, 10BUP-0.4NIC, and 20BUP-0.4NIC. On nicotine days, all rats were administered subcutaneously 0.4 mg/kg nicotine and had intermittent access to liquid sucrose. On intermixed non-reinforced days, rats were administered intraperitoneally saline, 10 or 20 mg/kg bupropion. Upon completion, a range of nicotine and bupropion doses were assessed before substitution tests with varenicline and sazetidine-A were conducted.

RESULTS

The SAL-0.4NIC and 10BUP-0.4NIC groups readily discriminated by session 8, as evidenced by increased dipper entries (goal-tracking) on nicotine days. The 20BUP-0.4NIC group was slower to acquire the discrimination. Female rats, regardless of group, had higher conditioned responding evoked by the lowest dose of nicotine (0.025 mg/kg) in the dose-effect curve. The discrimination required rats to learn to withhold responding to the training dose of bupropion. This withholding of excitatory dipper entries generalized to other doses. Varenicline and sazetidine-A partially substituted for the nicotine stimulus, and this pattern did not differ with training history.

CONCLUSIONS

We are the first to study a drug-drug discrimination using the DGT task. Females appeared to have a lower discrimination threshold for nicotine that was not impacted by the learning history. Further work on the importance of sex as a biological variable and how the complex interoceptive stimulus effects of nicotine can vary with training histories is needed.

The involvement of mesolimbic dopamine system in cotinine self-administration in rats

Cotinine is the major metabolite of nicotine and has recently been shown to be self-administered intravenously by rats. However, mechanisms underlying cotinine self-administration remained unknown. Mesolimbic dopamine system projecting from the ventral tegmental area (VTA) to nucleus accumbens (NAC) is closely implicated in drug reinforcement, including nicotine. The objective of the current study was to determine potential involvement of mesolimbic dopamine system in cotinine self-administration. An intracranial self-administration experiment demonstrates that cotinine at 0.88 and 1.76 ng/100 nl/infusion was self-infused into the VTA by rats. Rats produced more infusions of cotinine than vehicle and responded more on active than inactive lever during acquisition, reduced responding when cotinine was replaced by vehicle, and resumed responding during re-exposure to cotinine. Microinjection of cotinine at 1.76 ng/100 nl/infusion into the VTA increased extracellular dopamine levels within the NAC. Subcutaneous injection of cotinine at 1 mg/kg also increased extracellular dopamine levels within the NAC. Administration of the D1-like receptor antagonist SCH 23390 attenuated intravenous cotinine self-administration. On the other hand, bupropion, a catecholamine uptake inhibitor, did not significantly alter intravenous cotinine self-administration. These results suggest that activation of mesolimbic dopamine system may represent one cellular mechanism underlying cotinine self-administration. This shared mechanism between cotinine and nicotine suggests that cotinine may play a role in nicotine reinforcement.

Emerging Perspectives in the Management of Agitation in Alzheimer's Disease and Patients with Dementia

While Alzheimer's disease, the most common cause of dementia, is perhaps best characterized by cognitive decline, more than 90% of patients exhibit behavioural and psychological symptoms of dementia. Agitation in patients with dementia is often difficult to manage, and is associated with increased morbidity and mortality in patients and a heightened caregiver burden. Thus, effective management of dementia-related agitation (DRA) is vital. Care should first be taken to consider and address causes of agitation and aggression, after which non-pharmacological interventions should be employed. If non-pharmacological measures are unsuccessful in reducing DRA then medications should be considered, although none are approved by the Food and Drug Administration for this indication. Electroconvulsive therapy may be a promising option for patients with treatment-refractory DRA, although more studies are needed. While there are several drugs in the pipeline for DRA treatment, results from robust randomized clinical trials are necessary before they can be administered to patients. Thus, clinicians should employ current strategies to manage DRA to ensure holistic care for patients with Alzheimer's disease.

The compulsion zone explains the self-administration of cocaine, RTI-55 and bupropion in rats

Rats that reliably self-administered cocaine also reliably self-administered the cocaine analog RTI-55 and bupropion. The inter-injection intervals of these dopamine transporter (DAT) inhibitors were regular at a given unit dose and increased as a function of unit dose. However, the mean rate of intake differed widely, ranging from 731 to 459 to 2.1 nmol/kg∙min^-1 for bupropion, cocaine and RTI-55 respectively, a dramatic 348-fold range. An analysis of inter-injection intervals as a function of unit dose generated values for the mean satiety threshold of 50.6, 5.1 and 0.7 nmol/kg and t_1/2 of 56.7, 9.3 and 255.6 min for bupropion, cocaine and RTI-55, respectively. The difference in rate of intake of bupropion and RTI-55 relative to cocaine is a product of their 0.1 and 7.3 fold difference in PD potency and their 6.1 and 27.5 fold difference in t_1/2. Additionally, the relative durations of lever-pressing following termination of drug access correlated with the t_1/2 estimates. It is hypothesized this duration represents the time required for the drug concentration to fall from the satiety threshold below the priming threshold (the minimum DAT inhibitor level that will induce lever-pressing). This indicates that the time needed for an animal to cease lever pressing following termination of access to the DAT inhibitor is predominately a function of the PK properties of the agonist. The self-administration behavior paradigm in the context of the compulsion zone theory can be used as a bioassay to determine the PK/PD properties of indirect dopamine receptor agonists.

Sensitivity, specificity and limitation of in vitro hippocampal slice and neuron-based assays for assessment of drug-induced seizure liability

An effective in vitro screening assay to detect seizure liability in preclinical development can contribute to better lead molecule optimization prior to candidate selection, providing higher throughput and overcoming potential brain exposure limitations in animal studies. This study explored effects of 26 positive and 14 negative reference pharmacological agents acting through different mechanisms, including 18 reference agents acting on glutamate signaling pathways, in a brain slice assay (BSA) of adult rat to define the assay's sensitivity, specificity, and limitations. Evoked population spikes (PS) were recorded from CA1 pyramidal neurons of hippocampus (HPC) in the BSA. Endpoints for analysis were PS area and PS number. Most positive references (24/26) elicited a concentration-dependent increase in PS area and/or PS number. The negative references (14/14) had little effect on the PS. Moreover, we studied the effects of 15 reference agents testing positive in the BSA on spontaneous activity in E18 rat HPC neurons monitored with microelectrode arrays (MEA), and compared these effects to the BSA results. From these in vitro studies we conclude that the BSA provides 93% sensitivity and 100% specificity in prediction of drug-induced seizure liability, including detecting seizurogenicity by 3 groups of metabotropic glutamate receptor (mGluR) ligands. The MEA results seemed more variable, both quantitatively and directionally, particularly for endpoints capturing synchronized electrical activity. We discuss these results from the two models, comparing each with published results, and provide potential explanations for differences and future directions.

Obesity: The New Global Epidemic Pharmacological Treatment, Opportunities and Limits for Personalized Therapy

BACKGROUND

The increase in global obesity rates over the past three decades has been remarkable, a true epidemic, both in developed and in developing countries. The projections, based on current trends, suggest an increase in the prevalence of obesity at 60% in adult men, 40% in adult women and 25% in children in 2050. Given the limitations of lifestyle and surgery interventions bariatric, drug therapy approaches for the treatment of obesity, therefore become important options.

AIM

The purpose of this review is a review of the literature, based on research on MEDLINE until 2019, on the possible pharmacological options in the treatment of obesity.

RESULTS

Currently, the FDA has approved several molecules for the treatment of obesity, both in monotherapy and in combination. Pharmacological monotherapies focus mainly on a single protein target and include orlistat, lorcaserin and liraglutide while the combination molecules propose a multitarget approach and include phentermine/topiramate and naltrexone/bupropion. All the approved drugs showed, in the different studies, a weight reduction of at least 5%, compared to placebo, in 52 weeks of observation. Phentermine-topiramate and liraglutide have been associated with the highest probability of at least 5% weight loss. Liraglutide and naltrexone-bupropion had the lowest rates of therapy discontinuation due to adverse events.

CONCLUSION

The drugs, associated with the standard diet and/or exercise protocols, represent a good therapeutic opportunity to allow not only weight loss but also to reduce the risk of developing diseases caused by obesity, particularly cardiovascular diseases, and to maintain the set objectives over time. However, future research on the pharmacological treatment of obesity should encourage greater personalization of therapy, given the differences in safety, efficacy and response to therapy, in the different subpopulations of patients with obesity.

Bupropion-induced acute dystonia in a patient with bulimia nervosa: A case report

Bupropion is taken as an antidepressant for treatment of major depressive disorders, treatment of sexual side effects of selective serotonin reuptake inhibitors, and as a smoking cessation aid, however, it may result in adverse effects such as nausea, dry mouth, headache, insomnia, dizziness, anxiety, tremor, and constipation. We investigate the case of a 34-year-old woman with bulimia nervosa where acute dystonia was induced by bupropion in 8 months. Following this diagnosis and after normal tests and MRI results, the patient was advised to discontinue bupropion intake. In the follow-up done 2 weeks later, 3 months later, and 6 months later, no signs of acute dystonia was observed. A physician who administers dopamine blocking agents must be aware of the prevalence of and the risk factors for acute dystonia and also the way of prevention and treatment.

Probing the Release of Bupropion and Naltrexone Hydrochloride Salts from Biopolymeric Matrices of Diverse Chemical Structures

In the last decades, the notion of including excipients in the formulations, as inert substances aiding production processes, has changed and they are recently viewed as multifunctional discrete entities. It is now well documented that excipients serve several roles, spreading from the stabilization and modified release, to providing biocompatible properties and targeting moieties. The aim of this study was to develop matrix-based oral drug delivery systems of bupropion hydrochloride (BUP·HCl) and naltrexone hydrochloride (NTX·HCl), suitable for releasing these active substances in a modified manner, providing a stable level of drug release, which is simultaneously therapeutically effective and non-toxic, thus reducing side effects, after a single dose administration, throughout the gastrointestinal tract. The new formulations, employing hydroxypropylmethycellulose (HPMC K15M) (a cellulosic polymer, which, generally hydrates to form a gelatinous layer that is critical to prevent wetting and rapid drug release from the matrices), poly(methacylic acid-co-ethyl acrylate) 1:1 (Eudragit^® L100-55: effective for site specific drug delivery in intestine), poly(ethylene oxide) (PEO) (7 × 10⁶: a high molecular weight polymer, water-soluble, in micro-granular powder form), as the rate controlling polymers, were chosen to lead to a "soothing out" release pattern of these drugs, at 0 ≤ t ≤ 120 min. Moreover, the release of the two drugs from the ulvan-based tablets, was found to follow the desired profile, throughout the entire course of the dissolution experiments.

Anticholinergic symptoms in a patient with a bupropion overdose successfully managed with physostigmine: a case report

We report the case of anticholinergic poisoning in a patient suffering from an overdose of bupropion. The patient presented with bilateral mydriasis, involuntary movements and signs of agitation. Bupropion is commonly used as antidepressant and smoking cessation aid. It inhibits neuronal reuptake of dopamine and norepinephrine and also antagonizes acetylcholine at the level of the nicotinic receptor sites. So far bupropion overdose resulting in symptoms mimicking an anticholinergic syndrome has rarely been reported in literature. In this case, one milligram of intravenous physostigmine, an acetylcholinesterase inhibitor, rapidly resolved patient agitation and mydriasis. This case indicates that physostigmine might be used as an antidote to quickly reverse the central and peripheral anticholinergic symptoms in patients with an overdose of bupropion. Erratum This article is the corrected version of the article published in issue 2020/3, pages 137-140. Typos and order of authors have now been corrected. With apologies to the authors.

Bupropion increases cerebral activation in auditory affective processing: A randomized controlled fMRI study

INTRODUCTION

Bupropion is an antidepressant with less possibility to give rise to emotional blunting as side effect, and it also acts on improving negative self-recognition in a depressive state. Previous neuroimaging studies indicated a change in brain function by facial expression as an effect of antidepressants. As well as facial expression, vocal affective processing is essential for accurately recognizing another's feelings, but to our knowledge, no study has investigated whether bupropion affects the cerebral function of recognition of auditory affective processing. In this study, we aimed to investigate the acute effect of bupropion on cerebral response to vocal affective processing.

METHODS

Sixteen healthy volunteers (male = 8) participated in this study. With a randomized placebo-controlled within-subject trial, two series of fMRI scans, using either placebo or bupropion (150 mg), were examined. An auditory emotional valence judgement task was performed during fMRI scanning. The acute effects of bupropion on cerebral activation in the emotional circuit and behavioral performance during emotional processing were analyzed.

RESULTS

Compared with placebo, bupropion caused a significantly greater activation of emotional voices in the left insula and right superior temporal gyrus, whereas the amygdala was not activated. By bupropion, a significantly greater activation of the positive emotional circuit was observed at the superior temporal gyrus and middle frontal gyrus. As for behavioral performance, no significant difference was observed between placebo and bupropion.

CONCLUSIONS

Our findings suggest that bupropion enhances the cerebral response to affective processing, especially positive emotional vocalizations, indicating a possible mechanism underlying the therapeutic effects for patients with depression.

Recent developments in geriatric psychopharmacology

INTRODUCTION

There is a tremendous growing need to address the burden of geriatric psychiatric disorders. Recent developments relevant to geriatric psychiatry have focused on Alzheimer's disease (AD), severe/refractory depression, and cancer/end of life care.

AREAS COVERED

This is a non-systematic, narrative review (databases and websites for search: PubMed, Google Scholar, Medscape, ClinicalTrials.gov; focusing on the last 6 years), and covers developments in disease-modifying therapies for AD, diagnostic radiotracers for AD, medications for neuropsychiatric symptoms of dementia, ketamine/esketamine, psychedelics, and cannabinoids.

EXPERT OPINION

The focus of on-going trials of anti-amyloid agents has been on individuals with very early stage AD; several agents are under phase 3 investigation, and aducanumab is under FDA review. Amyloid and tau PET scans have been approved by the FDA to assist in the diagnoses of AD. Promising pharmaceuticals for neuropsychiatric symptoms of dementia include pimavanserin, brexpiprazole, escitalopram, dextromethorphan/quinidine, and lithium. Esketamine, although approved for treatment-resistant depression in general adults, failed to demonstrate efficacy in elderly patients in a phase 3 trial. There is preliminary evidence for benefit of psychedelic-assisted psychotherapy in end-of-life and cancer-related depression/anxiety. Evidence for the use of cannabinoids is currently lacking.

5-HT2A and 5-HT2C receptors as potential targets for the treatment of nicotine use and dependence

Nicotine use and dependence, typically achieved through cigarette smoking, but increasingly through vape products, is the leading cause of preventable death today. Despite a recognition that many current smokers would like to quit, the success rate at doing so is low and indicative of the persistent nature of nicotine dependence and the high urge to relapse. There are currently three main forms of pharmacotherapy approved as aids to treat nicotine dependence: a variety of nicotine replacement products (NRT's), the mixed NA/DA reuptake inhibitor bupropion (Zyban®), and the preferential nicotinic α4β2 receptor agonist drug, varenicline (Chantix®); the latter being generally recognized to be the most effective. However, each of these approaches afford only limited efficacy, and various other pharmacological approaches are being explored. This chapter focusses on approaches targeted to the serotonin (5-HT) system, namely, selective serotonin reuptake inhibitors (SSRI's) which served a pioneer role in the investigation of serotoninergic modulators in human smoking cessation trials; and secondly drugs selectively interacting with the 5-HT2A and 5-HT2C receptor systems. From an efficacy perspective, measured as smoking abstinence, the 5-HT2A agonist psychedelics, namely psilocybin, seem to show the most promise; although as the article highlights, these findings are both preliminary and there are significant challenges to the route to approval, and therapeutic use of this class should they reach approval status. Additional avenues include 5-HT2C receptor agonists, which until recently was pioneered by lorcaserin, and 5-HT2A receptor antagonists represented by pimavanserin. Each of these approaches has distinct profiles across preclinical tests of nicotine dependence, and may have therapeutic potential. It is anticipated as diagnostic and predictive biomarkers emerge, they may provide opportunities for subject stratification and opportunities for personalizing smoking cessation treatment. The clinical assessment of SSRI, 5-HT2A and/or 5-HT2C receptor-based treatments may be best served by this process.

Energizing effects of bupropion on effortful behaviors in mice under positive and negative test conditions: modulation of DARPP-32 phosphorylation patterns

Motivational symptoms such as anergia, fatigue, and reduced exertion of effort are seen in depressed people. To model this, nucleus accumbens (Nacb) dopamine (DA) depletions are used to induce a low-effort bias in rodents tested on effort-based decision-making. We evaluated the effect of the catecholamine uptake blocker bupropion on its own, and after administration of tetrabenazine (TBZ), which blocks vesicular storage, depletes DA, and induces depressive symptoms in humans. Male CD1 mice were tested on a 3-choice-T-maze task that assessed preference between a reinforcer involving voluntary physical activity (running wheel, RW) vs. sedentary activities (sweet food pellet intake or a neutral non-social odor). Mice also were tested on the forced swim test (FST), two anxiety-related measures (dark-light box (DL), and elevated plus maze (EPM)). Expression of phosphorylated DARPP-32 (Thr34 and Thr75) was evaluated by immunohistochemistry as a marker of DA-related signal transduction. Bupropion increased selection of RW activity on the T-maze. TBZ reduced time running, but increased time-consuming sucrose, indicating an induction of a low-effort bias, but not an effect on primary sucrose motivation. In the FST, bupropion reduced immobility, increasing swimming and climbing, and TBZ produced the opposite effects. Bupropion reversed the effects of TBZ on the T-maze and the FST, and also on pDARPP32-Thr34 expression in Nacb core. None of these manipulations affected anxiety-related parameters. Thus, bupropion improved active behaviors, which were negatively motivated in the FST, and active behaviors that were positively motivated in the T-maze task, which has implications for using catecholamine uptake inhibitors for treating anergia and fatigue-like symptoms.

Sex differences in nicotine-induced impulsivity and its reversal with bupropion in rats

BACKGROUND

Enhancement in cognitive impulsivity and the resulting alterations in decision making serve as a contributing factor for the development and maintenance of substance-use disorders. Nicotine-induced increases in impulsivity has been previously reported in male humans and rodents. Although the potential for sex differences in nicotine-induced impulsivity has not been examined.

AIMS AND METHODS

In the present study, male and female Sprague Dawley rats were submitted to a delay discounting task, in which several consecutive measures of self-control were taken. Firstly, rats were tested with vehicle, and next with nicotine doses of 0.4 and 0.8 mg/kg. Thereafter, chronic treatment with bupropion started, and the animals were tested again. Half the animals continued to receive 0.8 mg/kg of nicotine, while the rest received nicotine and also a daily dose of 30 mg/kg of bupropion.

RESULTS

When the animals were first tested with nicotine, female rats showed a significant nicotine dose dependent increase of impulsive behaviour, whereas male rats only showed a decrease on their elections of the larger but delayed reward under the highest dose of 0.8 mg/kg of nicotine. Treatment with bupropion blocked the effect of nicotine on decision making in female rats, as they showed results close to their baseline levels. On the other hand, bupropion did not affect the nicotine-induced delay discounting in male rats.

CONCLUSION

These findings demonstrate sexually dimorphic effects of nicotine on cognitive impulsivity which may help to shed light on nicotine use vulnerabilities observed in women.

Effects of chronic treatment with bupropion on self-administration of nicotine + cocaine mixtures in nonhuman primates

Chronic health problems associated with long-term nicotine use are the leading cause of preventable death in the United States. The use of tobacco products is 3-4 times greater among individuals with cocaine use disorder than that observed in the general population. This may reflect the propensity of nicotine to augment the reinforcing effects of cocaine. However, the mechanism of action of nicotine differs from that of cocaine, which presents a significant challenge for the development of pharmacotherapeutic interventions for the management of nicotine + cocaine polydrug abuse. Bupropion, an FDA-approved smoking cessation aid, has pharmacological actions at both monoamine transporters and nicotinic receptors, suggesting that it may be effective at decreasing nicotine + cocaine coabuse. Here, rhesus monkeys (n = 4) responded for food pellets and, separately, intravenous injections of nicotine, cocaine, or nicotine + cocaine mixtures under a second-order FR2(VR16:S) schedule of reinforcement during 7- to 10-day continuous treatment with saline or bupropion (1.0 and 1.8 mg/kg/hr). Results show that bupropion treatment dose-dependently decreased self-administration of nicotine combined with a low dose of cocaine (0.0032 mg/kg/inj); however, when the dose of cocaine in the mixture was higher (i.e., 0.01 mg/kg/inj), bupropion attenuated self-administration in only a subset of subjects. The effective dosage of bupropion increased responding for cocaine alone, nicotine alone, and for saline injections and significantly increased measures of daily activity. The apparent stimulant-like effects of bupropion at the dosage required to decrease cocaine + nicotine self-administration does not support its clinical use for the management of nicotine + cocaine polydrug abuse. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Anticholinergic symptoms in a patient with a bupropion overdose successfully managed with physostigmine: a case report

We report the case of anticholinergic poisoning in a patient suffering from an overdose of bupropion. The patient presented with bilateral mydriasis, involuntary movements and signs of agitation. Bupropion is commonly used as antidepressant and smoking cessation aid. It inhibits neuronal reuptake of dopamine and norepinephrine and also antagonizes acetylcholine at the level of the nicotinic receptor sites. So far bupropion overdose resulting in symptoms mimicking an anticholinergic syndrome has rarely been reported in literature. In this case, one milligram of intravenous physostigmine, an acetylcholinesterase inhibitor, rapidly resolved patient agitation and mydriasis. This case indicates that physostigmine might be used as an antidote to quickly reverse the central and peripheral anticholinergic symptoms in patients with an overdose of bupropion.

Pharmacological Augmentation in Unipolar Depression: A Guide to the Guidelines

BACKGROUND

Pharmacological augmentation is a recommended strategy for patients with treatment-resistant depression. A range of guidelines provide advice on treatment selection, prescription, monitoring and discontinuation, but variation in the content and quality of guidelines may limit the provision of objective, evidence-based care. This is of importance given the side effect burden and poorer long-term outcomes associated with polypharmacy and treatment-resistant depression. This review provides a definitive overview of pharmacological augmentation recommendations by assessing the quality of guidelines for depression and comparing the recommendations made.

METHODS

A systematic literature search identified current treatment guidelines for depression published in English. Guidelines were quality assessed using the Appraisal of Guidelines for Research and Evaluation II tool. Data relating to the prescription of pharmacological augmenters were extracted from those developed with sufficient rigor, and the included recommendations compared.

RESULTS

Total of 1696 records were identified, 19 guidelines were assessed for quality, and 10 were included. Guidelines differed in their quality, the stage at which augmentation was recommended, the agents included, and the evidence base cited. Lithium and atypical antipsychotics were recommended by all 10, though the specific advice was not consistent. Of the 15 augmenters identified, no others were universally recommended.

CONCLUSIONS

This review provides a comprehensive overview of current pharmacological augmentation recommendations for major depression and will support clinicians in selecting appropriate treatment guidance. Although some variation can be accounted for by date of guideline publication, and limited evidence from clinical trials, there is a clear need for greater consistency across guidelines to ensure patients receive consistent evidence-based care.

Involvement of glutamate and serotonin transmitter systems in male sex determination in Daphnia pulex

Environmental sex determination occurs in many organisms, however the means by which environmental stimuli are translated into endocrine messages remains poorly understood. The N-methyl-ᴅ-aspartate receptor (NMDAR) was evaluated as a candidate neural sensor of environmental signals linking environmental cues to endocrine responses using the crustacean Daphnia pulex. NMDAR agonists, modulators, and antagonists were evaluated for their ability to impact D. pulex male sex determination during early stages of reproductive maturity under conditions that simulated seasonal change. The antagonists MK-801 and desipramine significantly increased male sex determination. Both chemicals are also modulators of serotonergic and noradrenergic systems, thus, we evaluated several modulators of monoamine neurotransmission in an effort to discern which signaling pathways might contribute to male sex determination. Compounds that altered serotonergic signaling also stimulated male sex determination. The involvement of the glutamate and monoamine signaling in male sex determination was supported by the increase in mRNA levels of related receptors and transporters under conditions that stimulate male sex determination. Further, mRNA levels of components of the terminal endocrine pathway responsible for male sex determination were also elevated under stimulatory conditions. Overall, we provide evidence that glutamatergic and serotonergic systems function upstream of the endocrine regulation of male sex determination in early life stage daphnids.

Management of Dementia-Related Psychosis, Agitation and Aggression: A Review of the Pharmacology and Clinical Effects of Potential Drug Candidates

Along with cognitive decline, 90% of patients with dementia experience behavioral and psychological symptoms of dementia, such as psychosis, aggression, agitation, and depression. Atypical antipsychotics are commonly prescribed off-label to manage certain symptoms, despite warnings from the regulatory agencies regarding the increased risk of mortality associated with their use in elderly patients. Moreover, these compounds display a limited clinical efficacy, mostly owing to the fact that they were developed to treat schizophrenia, a disease characterized by neurobiological deficits. Thus, to improve clinical efficacy, it has been suggested that patients with dementia should be treated with exclusively designed and developed drugs that interact with pharmacologically relevant targets. Within this context, numerous studies have suggested druggable targets that might achieve therapeutically acceptable pharmacological profiles. Based on this, several different drug candidates have been proposed that are being investigated in clinical trials for behavioral and psychological symptoms of dementia. We highlight the recent advances toward the development of therapeutic agents for dementia-related psychosis and agitation/aggression and discuss the relationship between the relevant biological targets and their etiology. In addition, we review the compounds that are in the early stage of development (discovery or preclinical phase) and those that are currently being investigated in clinical trials for dementia-related psychosis and agitation/aggression. We also discuss the mechanism of action of these compounds and their pharmacological utility in patients with dementia.

Antenatal exposure to antidepressant drugs and the risk of neurodevelopmental and psychiatric disorders: a systematic review

Abstract: This study investigated whether antenatal exposure to antidepressants (ADs) increases the risks of autism spectrum disorders (ASD), attention deficit/hyperactivity disorders (ADHD), schizophrenia and other mental illnesses, and cognitive and developmental deficits in infants or preschool children. PubMed, EMBASE, BIREME/BVS databases were searched to identify studies examining associations of ADs in pregnancy with neurodevelopmental and psychiatric disorders. Twenty studies addressed ASD and/or ADHD risks while 30 focused on developmental and cognitive deficits in infants or preschool children. Most studies detected no association of antenatal AD with ASD after adjustment of risk ratios for maternal depression or psychiatric disorders. Some studies showed that maternal depression, regardless of whether it is treated or untreated, increased ASD risks. Seven out of 8 studies found no increase in ADHD risk associated with antenatal exposure to selective serotonin reuptake inhibitors, the most commonly used AD. No consistent evidence was found linking AD in pregnancy to neurocognitive developmental deficits in infants or preschool children. A residual confounding by indication (depression severity) remained in almost all studies. This systematic review found no consistent evidence suggesting that ADs in pregnancy increase risks of ASD, ADHD, and neurocognitive development deficits. Some studies, however, found evidence that maternal depression increases ASD risks.

Bupropion increases activation in nucleus accumbens during anticipation of monetary reward

RATIONALE

Bupropion is used for major depressive disorder, smoking cessation aid, and obesity. It blocks reuptake of dopamine and noradrenaline and antagonizes nicotinic acetylcholine receptor. Animal studies showed that bupropion enhanced rewarding effects. In addition, bupropion has the potential to treat patients with reward processing dysfunction. However, neural substrates underlying the bupropion effects on reward function in human subjects are not fully understood.

OBJECTIVES

We investigated single-dose administration of bupropion on neural response of reward anticipation in healthy subjects using a monetary incentive delay (MID) task by functional magnetic resonance imaging (fMRI), especially focusing on nucleus accumbens (NAc) activity to non-drug reward stimuli under bupropion treatment.

METHODS

We used a randomized placebo-controlled within-subject crossover design. Fifteen healthy adults participated in two series of an fMRI study, taking either placebo or bupropion. The participants performed the MID task during the fMRI scanning. The effects of bupropion on behavioral performance and blood oxygenation level-dependent (BOLD) signal in NAc during anticipation of monetary gain were analyzed.

RESULTS

We found that bupropion significantly increased BOLD responses in NAc during monetary reward anticipation. The increased BOLD responses in NAc were observed with both low and high reward incentive cues. There was no significant difference between placebo and bupropion in behavioral performance.

CONCLUSIONS

Our findings provide support for the notion that bupropion enhances non-drug rewarding effects, suggesting a possible mechanism underlying therapeutic effects for patients with motivational deficit.

NAChR α4β2 Subtype and their Relation with Nicotine Addiction, Cognition, Depression and Hyperactivity Disorder

BACKGROUND

Neuronal α4β2 nAChRs are receptors involved in the role of neurotransmitters regulation and release, and this ionic channel participates in biological process of memory, learning and attention. This work aims to review the structure and functioning of the α4β2 nAChR emphasizing its role in the treatment of associated diseases like nicotine addiction and underlying pathologies such as cognition, depression and attention-deficit hyperactivity disorder.

METHODS

The authors realized extensive bibliographic research using the descriptors "Nicotine Receptor α4β2" and "cognition", "depression", "attention-deficit hyperactivity disorder", besides cross-references of the selected articles and after analysis of references in the specific literature.

RESULTS

As results, it was that found 179 relevant articles presenting the main molecules with affinity to nAChR α4β2 related to the cited diseases. The α4β2 nAChR subtype is a remarkable therapeutic target since this is the most abundant receptor in the central nervous system.

CONCLUSION

In summary, this review presents perspectives on the pharmacology and therapeutic targeting of α4β2 nAChRs for the treatment of cognition and diseases like nicotine dependence, depression and attention-deficit hyperactivity disorder.

Spectrofluorimetric method for determination of bupropion in pharmaceutical dosage forms

OBJECTIVE

Bupropion is a noradrenaline and dopamine reuptake inhibitor which is used as an antidepressant drug. Few HPLC and spectrophotometric methods have been reported before for the determination of bupropion. Most of the previous methods reported for determination of bupropion in pharmaceutical dosage forms are somehow dangerous to health and environment because of using organic solvents.

METHOD

In the present method bupropion was determined in pharmaceutical dosage forms by spectrofluorimetry after ion-pair complex formation with eosin Y. The ion-pair complex formation was optimized for reagent amount, buffer pH and time.

RESULT

The developed method was linear over the range of 3-120μgmL^-1 with an acceptable precision (CV<1.5%) and accuracy (Error<1%).

CONCLUSION

The present method is applicable for determination of bupropion in pharmaceutical dosage forms for routine quality control analysis.

Efficacy and safety of bupropion hydrochloride extended-release versus escitalopram oxalate in Chinese patients with major depressive disorder: Results from a randomized, double-blind, non-inferiority trial

BACKGROUND

This study evaluated the non-inferiority of bupropion extended-release (XL) compared to escitalopram for acute-phase treatment of Chinese patients with major depressive disorder (MDD).

METHODS

This randomized (1:1), double-blind, active-control study conducted between February 2015 and October 2016 included patients with MDD (DSM-IV) (N = 538). The treatment phase had three dose levels (level 1 [Week 1], level 2 [Week 2-4], and level 3 [Week 5-8]), which included either bupropion XL 150 mg, 300 mg, 300 mg or escitalopram 10 mg, 10 mg, 10-20 mg (once-daily), respectively. Primary outcome was mean change from baseline in Hamilton Depression Rating Scale-17 (HAMD-17) total score at Week 8.

RESULTS

Overall, 534 patients (bupropion XL, n = 266; escitalopram, n = 268) received at least one dose of study medication. The least square mean (standard error) change from baseline in HAMD-17 total score at Week 8 was -14.5 (0.41) in bupropion XL group and -15.4 (0.39) in escitalopram group (mean difference: 0.8 [-0.27, 1.94]). The response rate was 69.6% versus 72.9%, remission rate was 39.7% versus 47.2%, sustained response rate was 51.6% versus 56.3%, and sustained remission rate was 25.5% versus 28.6%, respectively, for bupropion XL versus escitalopram group. Adverse events were reported by 313 patients (bupropion XL, n = 157; escitalopram, n = 156); the most common on-treatment adverse event in both groups was nausea (10.5% versus 18.7%, respectively).

LIMITATIONS

A non-inferiority short-term (8 weeks) study without a placebo arm.

CONCLUSION

Results from this study demonstrated that the efficacy of bupropion XL was non-inferior to that of escitalopram in Chinese patients with MDD.

Drug testing complementary metal-oxide-semiconductor chip reveals drug modulation of transmitter release for potential therapeutic applications

Neurodegenerative diseases, such as Parkinson’s disease, Alzheimer’s disease, and Huntington’s disease, are considered incurable and significantly reduce the quality of life of the patients. A variety of drugs that modulate neurotransmitter levels have been used for the treatment of the neurodegenerative diseases but with limited efficacy. In this work, an amperometric complementary metal‐oxide‐semiconductor (CMOS) chip is used for high‐throughput drug testing with respect to the modulation of transmitter release from single vesicles using chromaffin cells prepared from bovine adrenal glands as a model system. Single chromaffin cell amperometry was performed with high efficiency on the surface‐modified CMOS chip and follow‐up whole‐cell patch‐clamp experiments were performed to determine the readily releasable pool sizes. We show that the antidepressant drug bupropion significantly increases the amount of neurotransmitter released in individual quantal release events. The antidepressant drug citalopram accelerates rapid neurotransmitter release following stimulation and follow‐up patch‐clamp experiments reveal that this is because of the increase in the pool of readily releasable vesicles. These results shed light on the mechanisms by which bupropion and citalopram may be potentially effective in the treatment of neurodegenerative diseases. These results demonstrate that the CMOS amperometry chip technology is an excellent tool for drug testing to determine the specific mechanisms by which they modulate neurotransmitter release.

Sex differences in the effect of bupropion and naltrexone combination on alcohol drinking in mice

A fixed dose combination of bupropion (BPP) and naltrexone (NTX), Contrave®, is an FDA approved pharmacotherapy for the treatment of obesity. A recent study found that combining BPP with low-dose NTX reduced alcohol drinking in alcohol-preferring male rats. To explore potential pharmacological effects of the BPP + NTX combination on alcohol drinking, both male and female C57Bl/6J mice were tested on one-week drinking-in-the dark (DID) and three-week intermittent access (IA) models. Neuronal proopiomelanocortin (POMC) enhancer knockout (nPE^-/-) mice with hypothalamic-specific deficiency of POMC, and its bioactive peptides melanocyte stimulating hormone and beta-endorphin, were used as a genetic control for the effects of the BPP + NTX. A single administration of BPP + NTX (10 mg/kg + 1 mg/kg) decreased alcohol intake after DID in C57Bl/6J males, but not females. Also in C57Bl/6J males, BPP + NTX reduced intake of the caloric reinforcer sucrose, but not the non-caloric reinforcer saccharin. In contrast, BPP + NTX had no effect on alcohol DID in nPE^-/- males. Pretreatment with the selective melanocortin 4 receptor (MC4R) antagonist HS014 reversed the anti-dipsogenic effect of BPP + NTX on alcohol DID in C57Bl/6J males. In the 3-week chronic IA model, single or repeated administrations for four days of BPP + NTX reduced alcohol intake and preference in C57Bl/6J males only. The behavioral measures observed in C57Bl/6J mice provide clear evidence that BPP + NTX profoundly reduced alcohol drinking in males, but the doses tested were not effective in females. Furthermore, our results suggest a hypothalamic POMC/MC4R-dependent mechanism for the observed BPP + NTX effects on alcohol drinking in male mice.

Dopamine compartmentalization, selective dopaminergic vulnerabilities in Parkinson's disease and therapeutic opportunities

Progressive depletion of selected dopamine neurons is central to much Parkinson's disease (PD) disability. Although symptomatic treatments can ameliorate the disabilities that this neuronal depletion causes, no current strategy is documented to slow these losses. There is substantial evidence that dopamine in intracytoplasmic/extravesicular neuronal compartments can be toxic. Here, I review evidence that supports roles for dopamine compartmentalization, mediated largely by serial actions of plasma membrane SLC6A3/DAT and vesicular SLC18A2/VMAT2 transporters, in the selective patterns of dopamine neuronal loss found in PD brains. This compartmentalization hypothesis for the dopamine cell type specificity of PD lesions nominates available drugs for amelioration of damage arising from miscompartmentalized dopamine and raises cautions in using other drugs.

Systematic review of preclinical, clinical, and post-marketing evidence of bupropion misuse potential

Background: Bupropion is a substituted cathinone compound widely used as a first line or add-on treatment for depression, smoking cessation, and more recently in combination with naltrexone for weight loss. As abuse of synthetic cathinone compounds has received more attention in recent years, concern about the misuse potential of bupropion has grown as well. Objectives: We review bupropion pharmacology and assessments of misuse potential including preclinical evidence, human studies, and post-marketing surveillance of bupropion misuse. Methods: This review reports the results of a systematic review of publications evaluating the potential for bupropion to be misused. Publications were identified using PubMed and Medline through Ovid® as well as iterative bibliographic searches. A summary of data from informal sources of information including substance-user experience from online forum entries is included. Results: Preclinical evidence demonstrates some potential for misuse based on psychomotor, discrimination, self-administration, and conditioned place preference tasks. However, this potential is less than that of commonly misused stimulants. Studies in human populations similarly indicate that bupropion shares interoceptive effects with other stimulants, but lacks some key reinforcing effects of other stimulants. In the real-world setting, misuse of bupropion occurs, but is uncommon. Adverse effects of bupropion misuse are frequently cited as significant barriers to obtaining any desired interoceptive effect. Conclusions: While bupropion demonstrates some potential for misuse, pharmacological differences from other structurally-related stimulants limit bupropion's reinforcing effects. Without additional data indicating susceptibility of specific populations to bupropion misuse, there is no empirical data suggesting a need to modify bupropion prescribing patterns.

Nicotine Self-Administration as Paradigm for Medication Discovery for Smoking Cessation: Recent Findings in Medications Targeting the Cholinergic System

Tobacco kills every year approximately six million people as a direct result of direct use, and it is still considered one of the most excruciating threats for human health worldwide. The low successful rates of the currently available pharmacotherapies to assist in quitting tobacco use suggest there is a need for more effective treatments.The intravenous self-administration (IVSA) paradigm is considered the gold standard to study voluntary drug intake in animal models, including nicotine. The IVSA paradigm has been used to identify key mechanisms involved in the addictive properties of nicotine in both rodents and nonhuman primates. In this chapter we describe how the IVSA paradigm has served to further investigate the role of nicotinic acetylcholine receptors (nAChRs) in the reinforcing properties of nicotine. Notably, this review will cover recent advances (i.e., research carried out during the past decade) using the IVSA paradigm, with a focus on the status of research on current smoking cessation medications (such as varenicline and bupropion) and of other nAChR ligands.The combination of the IVSA paradigm with pharmacological and genetic tools (e.g., knockout animals) has greatly contributed to our understanding of the role of specific subtype nAChRs in nicotine reinforcement processes. We also discuss some of the limitations of the IVSA paradigm so these can be taken into consideration when interpreting and designing new studies.

A 10-year review of single medication double-dose ingestions in the nation's largest poison control system

BACKGROUND

Most Americans take at least one medication on a daily basis. Inadvertently ingesting a double-dose of a medication with a narrow therapeutic index may lead to adverse effects. When a patient or medical professional contacts the local poison center after an overdose, a poison specialist fields the incoming information and, depending on the caller, provides specific recommendations. We sought to determine which medication classes were most likely to lead to significant adverse outcomes when an extra dose was ingested.

METHODS

This was a retrospective review of all double-dose medication ingestions reported to the California Poison Control System (CPCS) between January 2006 and December 2015. Inclusion criteria were single-instance, single-medication ingestions where the dose was known. All ages and both sexes were included. We evaluated generalized outcomes per AAPCC criteria stratified as no effect, minor, moderate, major or death. We also documented specific symptoms and interventions noted by the poison control specialists.

RESULTS

Out of 1286 cases, 876 ingestions met the inclusion criteria. Medications with antihypertensive and behavior modulating effects each accounted for over a third of all moderate and major effects. The medications/medication classes implicated in the 12 major outcomes included propafenone, beta blockers (βBs), calcium channel blockers (CCBs), bupropion, and tramadol. Of these, vasoactive medications were associated with the most severe effects requiring cardiac pacing and vasopressor drips. Analgesics, antimicrobials, and anti-allergy medications were well tolerated. There were no deaths.

CONCLUSIONS

Major adverse outcomes after a double dose ingestion were rare. Most double dose medication ingestions can be safely monitored at home, albeit with a few exceptions. Vigilance is warranted in cases of βB and CCB ingestion due to the risk of hemodynamic collapse or seizures with tramadol and bupropion.