Safety and tolerability of anticonvulsant medication in bipolar disorder

The pharmacotherapeutic management of comorbid bipolar disorder and alcohol use disorder

INTRODUCTION

Comorbidity of bipolar disorder (BD) and alcohol use disorder (AUD) is very frequent resulting in detrimental outcomes, including increased mortality. Diagnosis of AUD in BD and vice versa is often delayed as symptoms of one disorder mimic and obscure the other one. Evidence for pharmacotherapies for people with comorbid BD and AUD remains limited, and further proof-of-concept studies are urgently needed.

AREAS COVERED

This paper explores the currently available pharmacotherapies for AUD, BD and their usefulness for comorbid BD and AUD. It also covers to some degree the epidemiology, diagnosis, and potential common neurobiological traits of comorbid BD and AUD.

EXPERT OPINION

The authors conclude that more controlled studies are needed before evidence-based guidance can be drawn up for clinician's use. Since there are no relevant pharmacological interactions, approved medications for AUD can also be used safely in BD. For mood stabilization, lithium should be considered first in adherent persons with BD and comorbid AUD. Alternatives include valproate, lamotrigine, and some atypical antipsychotics, with partial D2/D3 receptor agonism possibly being beneficial in AUD, too.

Long-Term Treatment of Bipolar Disorder with Valproate: Updated Systematic Review and Meta-analyses

LEARNING OBJECTIVE

After participating in this activity, learners should be better able to:• Evaluate the evidence regarding the effectiveness of long-term treatment of bipolar disorder with valproate.

BACKGROUND

Prophylactic treatment is critical for bipolar disorder (BD) patients. Valproate is commonly used for this purpose but lacks regulatory approval and carries appreciable risks.

METHODS

Systematic literature searching through June 2020 sought prospective trials lasting ≥12 months with adults diagnosed with BD to support comparisons of risk of new illness episodes with valproate versus placebo or other agents.

RESULTS

Included were 13 reports involving 9240 subjects treated for an average of 29.1 months (range, 12-124) in 21 trials: 9 were blinded, randomized trials (RCTs) of valproate versus placebo (n = 3), lithium (5), or olanzapine (1); 2 were unblinded RCTs versus lithium (1) or quetiapine (1); and 10 were open-label trials versus lithium (5), quetiapine (2), carbamazepine (1), lamotrigine (1), or olanzapine (1). Random-effects meta-analysis found valproate superior to placebo in 3 trials (odds ratio [OR] = 0.42 [95% confidence level (CI), 0.30-0.60]; p < .0001). In 11 trials, protective effects with valproate and lithium were similar (OR = 1.20 [CI, 0.81-1.79]; p = .36), as well in 5 comparisons versus antipsychotics quetiapine and olanzapine (OR = 0.96 [CI, 0.66-1.40]; p = .84), and 2 versus other mood-stabilizing anticonvulsants (carbamazepine and lamotrigine) (OR = 1.30 [CI, 0.75-2.26]; p = .34). Valproate was nonsignificantly more effective versus new mania than depression (χ2 = 3.03; p = .08).

CONCLUSIONS

Valproate was more effective than placebo in preventing new BD episodes of mania or depression, and not significantly different from lithium, second-generation antipsychotics, or other anticonvulsants. Overall benefits were nonsignificantly greater versus mania than bipolar depression.

The risks associated with the use of lamotrigine during pregnancy

OBJECTIVE

This paper reviewed the relevant literature on the effects of lamotrigine on pregnancy outcomes to provide useful information regarding lamotrigine use in pregnant women with bipolar disorder.

METHODS

A systematic search of electronic databases and other original sources was conducted that examined the effects of lamotrigine on pregnancy outcomes.

RESULTS

It is not clear that foetuses of lamotrigine-exposed pregnant women are at higher risk of malformation or neurodevelopmental delay. When treating pregnant women with bipolar disorder, the risks associated with lamotrigine use have to be balanced with the risks of uncontrolled maternal symptoms. The information obtained from our review of psychotropic medications will assist clinicians in managing pregnant women with bipolar disorder.

CONCLUSIONS

Although lamotrigine has emerged as the safest mood stabiliser for use during pregnancy based on the clinical evidence thus far, further studies are needed to inform the best clinical practice when treating bipolar disorder in pregnant women.

HCN Channel Targets for Novel Antidepressant Treatment

Major depressive disorder (MDD) is a chronic and potentially life threatening illness that carries a staggering global burden. Characterized by depressed mood, MDD is often difficult to diagnose and treat owing to heterogeneity of syndrome and complex etiology. Contemporary antidepressant treatments are based on improved monoamine-based formulations from serendipitous discoveries made > 60 years ago. Novel antidepressant treatments are necessary, as roughly half of patients using available antidepressants do not see long-term remission of depressive symptoms. Current development of treatment options focuses on generating efficacious antidepressants, identifying depression-related neural substrates, and better understanding the pathophysiological mechanisms of depression. Recent insight into the brain's mesocorticolimbic circuitry from animal models of depression underscores the importance of ionic mechanisms in neuronal homeostasis and dysregulation, and substantial evidence highlights a potential role for ion channels in mediating depression-related excitability changes. In particular, hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are essential regulators of neuronal excitability. In this review, we describe seminal research on HCN channels in the prefrontal cortex and hippocampus in stress and depression-related behaviors, and highlight substantial evidence within the ventral tegmental area supporting the development of novel therapeutics targeting HCN channels in MDD. We argue that methods targeting the activity of reward-related brain areas have significant potential as superior treatments for depression.

Functional Studies of Sodium Channels: From Target to Compound Identification

Over the last six decades, voltage-gated sodium (Na_v ) channels have attracted a great deal of scientific and pharmaceutical interest, driving fundamental advances in both biology and technology. The structure and physiological function of these channels have been extensively studied; clinical and genetic data have uncovered their implication in diseases such as epilepsy, arrhythmias, and pain, bringing them into focus as current and future drug targets. While different techniques have been established to record the activity of Na_v channels, proper determination of their properties still presents serious challenges, depending upon the experimental conditions and the desired subtype of channel to be characterized. The aim of this unit is to review the characteristics of Na_v channels, their properties, the cells in which they can be studied, and the currently available techniques. Topics covered include the determination of Na_v -channel biophysical properties as well as the use of toxins to discriminate between subtypes using electrophysiological or optical methods. Perspectives on the development of high-throughput screening assays with their advantages and limitations are also discussed to allow a better understanding of the challenges encountered in voltage-gated sodium channel preclinical drug discovery. © 2016 by John Wiley & Sons, Inc.

Safety of Long-term Use of Lamotrigine for the Treatment of Psychiatric Disorders

OBJECTIVES

Lamotrigine (LTG) is a drug commonly used to treat epilepsy and can also be used to manage mood disorders, such as bipolar disorder. One of the most dangerous adverse effects of LTG is skin rash, which can make early cessation necessary. Here, we examine the adverse effects associated with long-term use of LTG for the treatment of mood disorders.

METHODS

Data were obtained from the medical records of 101 psychiatric patients who were prescribed long-term treatment with LTG. Patients were retrospectively divided into those who discontinued treatment within 6 months and those who continued for longer, and the groups were compared for adverse effects. We also compared the incidence of adverse effects in high and low doses.

RESULTS

Fifty-four patients continued LTG treatment for 6 months or longer; 47 discontinued within 6 months. A history of allergy was more prevalent among the patients who discontinued treatment early than in those who continued. Of the patients who continued treatment for 6 months or longer, only 2 later discontinued treatment because of adverse effects. Lamotrigine monotherapy showed no difference in the incidence of adverse effects for different doses of LTG (>200 mg = 4.8% vs >100 mg, ≤200 mg = 7.7%; P = 1, vs >50 mg, ≤100 mg = 0%; P = 1 vs ≤50 mg = 0%; P = 1).

CONCLUSIONS

Clinicians must be mindful of the adverse effects occurring early during the titration phase. However, long-term use of LTG was very well tolerated, even at high maintenance doses.