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Δευτέρα 9 Δεκεμβρίου 2019

Cognitive Impairment in Patients with Bipolar Disorder: Impact of Pharmacological Treatment

Abstract

Bipolar disorder is an illness characterised by periods of elated and depressed mood. These mood episodes are associated with changes in cognitive function and there is evidence to suggest that cognitive dysfunction persists during euthymia. The extent to which this is a function of the illness or a result of treatment is less clear. In this narrative review, we explore the impact of commonly used medications for bipolar disorder on cognitive function. Specific impairments in executive function and verbal memory have been noted in bipolar disorder. The impact of pharmacological treatments upon cognitive function is mixed with a number of studies reporting conflicting results. Interpretation of the data is further complicated by the variety of cognitive tests employed, study design, the relatively small numbers of patients included and confounding by indication. Overall, there is some evidence that while lithium improves some cognitive domains, it impedes others. Antipsychotics may be deleterious to cognition, although this may relate to the patient population in which they are prescribed. Sodium valproate is also associated with worse cognitive outcomes, while the impact of other antiepileptics is unclear. Overall the quality of evidence is poor and is derived from a relatively small number of studies that often do not account for the significant heterogeneity of the disorder or common comorbidities. The use of consistent methodologies and measures of cognition across studies, as well as in naturalistic settings, would enable more certain conclusions to be drawn.

Emergency Department Initiation of Buprenorphine for Opioid Use Disorder: Current Status, and Future Potential

Abstract

Patients experiencing the consequences of opioid use often present to the emergency department (ED) at times of crisis, such as following overdose or when in withdrawal. This highlights the important role of the ED in recognizing opioid use disorder and engaging these patients into ongoing treatment. Given the limited ability of the healthcare system to provide timely addiction treatment, initiation of therapy in the ED, with referral to long-term care, is associated with improved outcomes. The primary evidence-based treatment used in EDs for this indication is buprenorphine. Although clinicians may find the initiation of buprenorphine therapy daunting, it is straightforward and well-tolerated, and many of the barriers are surmountable. This article addresses these barriers, which include stigma, complicated pharmacology, and confusing regulations, and provides a basis for the use of buprenorphine in acute care clinical practice.

An Update on Vitamin D and Disease Activity in Multiple Sclerosis

Abstract

Vitamin D and its main active metabolite 1,25-dihydroxyvitamin D serve a crucial role in maintenance of a healthy calcium metabolism, yet have additional roles in immune and central nervous system cell homeostasis. Serum levels of 25-hydroxyvitamin D are a biomarker of future disease activity in patients with early relapsing–remitting multiple sclerosis (RRMS), and vitamin D supplementation in patients with low circulating 25-dihydroxyvitamin D levels has been anticipated as a potential efficacious treatment strategy. The results of the first large randomized clinical trials (RCTs), the SOLAR and CHOLINE studies, have now been published. The SOLAR study compared 14,000 IU of vitamin D3 (cholecalciferol) per day with placebo for 48 weeks in 232 randomized patients, whereas CHOLINE compared vitamin D3 100,000 IU every other week with placebo for 96 weeks in 129 randomized patients. All patients in both studies also used interferon-β-1a. None of the studies met their primary endpoints, which were no evidence of disease activity (NEDA-3) at 48 weeks in SOLAR and annualized relapse rate at 96 weeks in CHOLINE. Both studies did, however, suggest modest effects on secondary endpoints. Thus, vitamin D reduced the number of new or enlarging lesions and new T2 lesions in SOLAR, and the annualized relapse rate and number of new T1 lesions, volume of hypointense T1 lesions, and disability progression in the 90 patients who completed 96 weeks’ follow-up in CHOLINE. We conclude that none of the RCTs on vitamin supplementation in MS have met their primary clinical endpoint in the intention to treat cohorts. This contrasts the observation studies, where each 25 nmol/l increase in 25-hydroxyvitamin D levels were associated with 14–34% reduced relapse risk and 15–50% reduced risk of new lesions on magnetic resonnance imaging. This discrepancy may have several explanations, including confounding and reverse causality in the observational studies. The power calculations of the RCTs have been based on the observational studies, and the RCTs may have been underpowered to detect less prominent yet important effects of vitamin D supplementation. Although the effect of vitamin D supplementation is uncertain and less pronounced than suggested by observational studies, current evidence still support that people with MS should avoid vitamin D insufficiency, and preferentially aim for vitamin D levels around 100 nmol/L or somewhat higher.

Ischemic and Thrombotic Events Associated with Concomitant Xa-inhibiting Direct Oral Anticoagulants and Antiepileptic Drugs: Analysis of the FDA Adverse Event Reporting System (FAERS)

Abstract

Introduction

Factor Xa-inhibiting direct oral anticoagulants (FXa-DOACs) undergo hepatic metabolism via cytochrome P-450 (CYP450). Concomitant use of rifampicin, an inducer of these enzymes, with FXa-DOACs, has been shown to decrease FXa-DOAC concentrations in healthy subjects. Several common antiepileptic drugs (AEDs) are known to induce CYP450 enzymes as well. However, little is known regarding the impact of this potential interaction on treatment outcomes with FXa-DOACs.

Methods

We analyzed adverse event cases submitted to the Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) from January 2013 to December 2018. We compared the proportion of cases reporting thromboembolic and ischemic adverse events (TAIAEs) with the concomitant use of FXa-DOACs and enzyme-inducing AEDs to the proportion of cases with FXa-DOACs and other AEDs.

Results

During this period, 9693 adverse event cases reported concomitant use of FXa-DOACs and AEDs. Almost all reports (> 99%) involved the use of rivaroxaban or apixaban. Compared with other AEDs, enzyme-inducing AEDs were associated with an 86% increase in the odds of reporting TAIAEs [reporting odds ratio (ROR) 1.86, 95% confidence interval (CI) 1.61–2.15; p < 0.0001]. In secondary separate analyses of rivaroxaban and apixaban, enzyme-inducing AEDs were similarly associated with increased reporting of a TAIAE (ROR 1.79, 95% CI 1.50–2.12, and ROR 1.88, 95% CI 1.41–2.48, respectively).

Conclusion

Using real world data, we observed an increase in the odds of reporting anticoagulation treatment failure among patients treated with FXa-DOACs and concomitant enzyme-inducing AEDs compared to those treated with other AEDs.

Novel IDH1-Targeted Glioma Therapies

Abstract

Mutations in the isocitrate dehydrogenase (IDH) 1 gene are commonly found in human glioma, with the majority of low-grade gliomas harboring a recurrent point mutation (IDH1 R132H). Mutant IDH reveals an altered enzymatic activity leading to the synthesis of 2-hydroxyglutarate, which has been implicated in epigenetic mechanisms of oncogenesis. Nevertheless, it is unclear exactly how IDH mutations drive glioma initiation and progression, and it is also not clear why tumors with this mutation generally have a better prognosis than IDH wild-type tumors. Recognition of the high frequency of IDH mutations in glioma [and also in other malignancies, including acute myeloid leukemia (AML) and cholangiocarcinoma] have led to the development of a number of targeted agents that can inhibit these enzymes. Enasidenib and ivosidenib have both gained regulatory approval for IDH mutant AML. Both agents are still in early clinical phases for glioma therapy, as are a number of additional candidates (including AG-881, BAY1436032, and DS1001). A marked clinical problem in the development of these agents is overcoming the blood–brain barrier. An alternative approach to target the IDH1 mutation is by the induction of synthetic lethality with compounds that target poly (ADP-ribose) polymerase (PARP), glutamine metabolism, and the Bcl-2 family of proteins. We conclude that within the last decade, several approaches have been devised to therapeutically target the IDH1 mutation, and that, potentially, both IDH1 inhibitors and synthetic lethal approaches might be relevant for future therapies.

Fingolimod Increases Brain-Derived Neurotrophic Factor Level Secretion from Circulating T Cells of Patients with Multiple Sclerosis

Abstract

Background

The pathophysiology of multiple sclerosis involves an autoimmune and a neurodegenerative mechanism. Central nervous system-infiltrating immune cells in multiple sclerosis also possess a neuroprotective activity through secretion of neurotrophins, such as brain-derived neurotrophic factor. Fingolimod was shown to slow the progression of disability and loss of brain volume.

Objective

The objective of this study was to explore whether fingolimod induces secretion of neurotrophins by immune cells.

Methods

Blood was drawn from 21 patients before the initiation of treatment with fingolimod and at 6 and 12 months of follow-up. The levels of the neurotrophic factors brain-derived neurotrophic factor, glial cell-derived neurotrophic factor, β-nerve growth factor, neurotrophin-3, neurotrophin-4, basic fibroblast growth factor, epidermal growth factor, and vascular endothelial growth factor were screened in the supernatants of separated T cells and monocyte cultures using a customized, multiplex enzyme-linked immunosorbent assay. Brain-derived neurotrophic factor levels were further validated by a specific enzyme-linked immunosorbent assay.

Results

Treatment with fingolimod significantly increased brain-derived neurotrophic factor secretion from T cells. A specific enzyme-linked immunosorbent assay confirmed these results in the supernatant of T cells after 6 and 12 months of therapy.

Conclusions

T cells that reach the bloodstream of fingolimod-treated patients with multiple sclerosis may contribute to the neuroprotective effect of this therapy by increased secretion of brain-derived neurotrophic factor. This mechanism of action of fingolimod in patients with multiple sclerosis has not been previously reported.

Adverse Events Associated with Melatonin for the Treatment of Primary or Secondary Sleep Disorders: A Systematic Review

Abstract

Background

Melatonin is widely available either on prescription for the treatment of sleep disorders or as an over-the-counter dietary supplement. Melatonin has also recently been licensed in the UK for the short-term treatment of jetlag. Little is known about the potential for adverse events (AEs), in particular AEs resulting from long-term use. Concern has been raised over the possible risks of exposure in certain populations including pre-adolescent children and patients with epilepsy or asthma.

Objectives

The aim of this systematic review was to assess the evidence for AEs associated with short-term and longer-term melatonin treatment for sleep disorders.

Methods

A literature search of the PubMed/Medline database and Google Scholar was conducted to identify randomised, placebo-controlled trials (RCTs) of exogenous melatonin administered for primary or secondary sleep disorders. Studies were included if they reported on both the types and frequencies of AEs. Studies of pre-term infants, studies of < 1 week in duration or involving single doses of melatonin and studies in languages other than English were excluded. Findings from open-label studies that raised concerns relating to AE reports in patients were also examined. Studies were assessed for quality of reporting against the Consolidated Standards of Reporting Trials (CONSORT) checklist and for risk of bias against the Cochrane Collaboration risk-of-bias criteria.

Results

37 RCTs met criteria for inclusion. Daily melatonin doses ranged from 0.15 mg to 12 mg. Subjects were monitored for up to 29 weeks, but most studies were of much shorter duration (4 weeks or less). The most frequently reported AEs were daytime sleepiness (1.66%), headache (0.74%), other sleep-related AEs (0.74%), dizziness (0.74%) and hypothermia (0.62%). Very few AEs considered to be serious or of clinical significance were reported. These included agitation, fatigue, mood swings, nightmares, skin irritation and palpitations. Most AEs either resolved spontaneously within a few days with no adjustment in melatonin, or immediately upon withdrawal of treatment. Melatonin was generally regarded as safe and well tolerated. Many studies predated publication of the CONSORT checklist and consequently did not conform closely to the guidelines. Similarly, only eight studies were judged ‘good’ overall with respect to the Cochrane risk-of-bias criteria. Of the remaining papers, 16 were considered ‘fair’ and 13 ‘poor’ but publication of almost half of the papers preceded that of the earliest version of the guidelines.

Conclusion

Few, generally mild to moderate, AEs were associated with exogenous melatonin. No AEs that were life threatening or of major clinical significance were identified. The scarcity of evidence from long-term RCTs, however, limits the conclusions regarding the safety of continuous melatonin therapy over extended periods. There are insufficient robust data to allow a meaningful appraisal of concerns that melatonin may result in more clinically significant adverse effects in potentially at-risk populations. Future studies should be designed to comply with appropriate quality standards for RCTs, which most past studies have not.

Acknowledgement to Referees

Clinically Significant Drug–Drug Interactions with Agents for Attention-Deficit/Hyperactivity Disorder

Abstract

This article provides an overview of the pharmacokinetic drug–drug interactions (DDIs) for agents prescribed for attention-deficit/hyperactivity disorder (ADHD). Polypharmacy in the treatment of patients with ADHD leads to high exposures to DDIs and possibly adverse safety outcomes. We performed a systematic search of DDI reports for ADHD agents in Embase and Medline. We also searched for agents in the pharmacological pipeline, which include (1) mazindol, molindone and viloxazine, which were previously prescribed for other indications; (2) centanafadine and AR-08, never before approved; and (3) two extracts (Polygala tenuifolia extract and the French maritime pine bark extracts). The identified literature included case reports, cross-sectional, cross-over and placebo-controlled studies of patient cohorts and healthy volunteers. The DDIs were classified as follows: ADHD agents acting as perpetrators, i.e., affecting the clearance of co-prescribed agents (victim drugs), or ADHD agents being the victim drugs, being affected by other agents. Ratios for changes in pharmacokinetic parameters before and after the DDI were used as a rough estimate of the extent of the DDI. Alcohol may increase plasma dextroamphetamine concentrations by presystemic effects. Until studies are done to orient clinicians regarding dosing changes, clinicians need to be aware of the potential for cytochrome P450 (CYP) 2D6 inhibitors to increase amphetamine levels, which is equivalent to increasing dosages. Atomoxetine is a wide therapeutic window drug. The CYP2D6 poor metabolizers who do not have CYP2D6 activity had better atomoxetine response, but also an increased risk of adverse effects. CYP2D6 inhibitors have been used to increase atomoxetine response in CYP2D6 extensive metabolizers. Guanfacine is mainly metabolized by CYP3A4, which can be induced and inhibited. The package insert recommends that in guanfacine-treated patients, after adding potent CYP3A4 inducers, the guanfacine dose should be doubled; after adding potent CYP3A4 inhibitors the guanfacine dose should be halved. Based on a phenobarbital case report and our experience with CYP3A4-metabolized antipsychotics, these correction factors may be too low. According to two case reports, carbamazepine is a clinically relevant inducer of methylphenidate (MPH). A case series study suggested that MPH may be associated with important elevations in imipramine concentrations. Due to the absence of or limitations in the data, no comments for clinicians can be provided on the pharmacokinetic DDIs for clonidine, centanafadine, mazindol, molindone, AR-08, P. tenuifolia extract and the French maritime pine bark extracts. According to currently available data, clinicians should not expect that ADHD drugs modify each other’s serum concentrations. A summary table for clinicians provides our current recommendations on pharmacokinetic DDIs of ADHD agents based on our literature review and the package inserts; whenever it was possible, we provide information on serum concentrations and dose correction factors. There will be a need to periodically update these recommendations and these correction factors as new knowledge becomes available.

Psychostimulants/Atomoxetine and Serious Cardiovascular Events in Children with ADHD or Autism Spectrum Disorder

Abstract

Background

Psychostimulants and atomoxetine have been shown to increase blood pressure, heart rate, and QT interval in children and adolescents; however, based on current literature, it is unclear if these “attention-deficit/hyperactivity disorder (ADHD) medications” are also associated with serious cardiovascular (SCV) events. We addressed this question in commonly exposed groups of children and adolescents with either ADHD or autism spectrum disorder (ASD).

Methods

Using commercial (years 2000–2016) and Medicaid (years 2012–2016) administrative claims data from the United States (US), we conducted two case–control studies, nested within respective cohorts of ADHD and ASD children aged 3–18 years. We defined cases by a composite outcome of stroke, myocardial infarction, or serious cardiac arrhythmia. For each case, we matched ten controls on age, sex, and insurance type. We conducted conditional logistic regression models to test associations between SCV outcomes and a primary exposure definition of current ADHD medication use. Additionally, we controlled for resource use, cardiovascular and psychiatric comorbidities, and use of medications in a variety of sensitivity analyses.

Results

We identified 2,240,774 children for the ADHD cohort and 326,221 children for the ASD cohort. For ADHD, 33.9% of cases (63 of 186) versus 32.2% of controls (598 of 1860) were exposed, which yielded an odds ratio (OR) and 95% confidence interval (CI) of 1.08 (0.78–1.49). For ASD, 12.5% of cases (6 of 48) versus 22.1% of controls (106 of 480) were exposed [OR 0.49 (0.20–1.20)]. Covariate-adjusted results and results for individual outcomes and other exposure definitions were consistent with no increased risk of SCV events.

Conclusion

Using large US claims data, we found no evidence of increased SCV risk in children and adolescents with ADHD or ASD exposed to ADHD medications.

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