Lamotrigine vs. lamotrigine plus divalproex in randomized, placebo-controlled maintenance treatment for bipolar depression

Preventing new episodes of bipolar disorder in adults: Systematic review and meta-analysis of randomized controlled trials

Uncertainty remains regarding the relative efficacy of maintenance pharmacotherapy for bipolar disorder (BD), and available data require updating. The present systematic review and meta-analysis aims to consolidate the evidence from the highest quality randomized controlled trials (RCTs) published up to July 2021, overcoming the limitations of earlier reviews. The PubMed and the Cochrane Central Register of Controlled Trials were searched for double-blind RCTs involving lithium, mood stabilizing anticonvulsants (MSAs), antipsychotics, antidepressants, and other treatments. Rates of new mood episodes with test vs. reference treatments (placebo or alternative active agent) were compared by random-effects meta-analysis. Polarity index was calculated for each treatment type. Eligible trials involved ≥6 months of maintenance follow up. Of 2,158 identified reports, 22 met study eligibility criteria, and involved 7,773 subjects stabilized for 1-12 weeks and followed-up for 24-104 weeks. Psychotropic monotherapy overall (including lithium, MSAs, and second generation antipsychotics (SGA) was more effective in preventing new BD episodes than placebo (odds ratio, OR=0.42; 95% confidence interval, CI 0.34-0.51, p<0.00001). Significantly lower risk of new BD episodes was observed with the following individual drugs: aripiprazole, asenapine, lithium, olanzapine, quetiapine, and risperidone long-acting (ORs varied 0.19-0.46). Adding aripiprazole, divalproex, quetiapine, or olanzapine/risperidone to lithium or an MSA was more effective compared with lithium or MSA monotherapy (OR=0.37; 95%CI 0.25-0.55, p<0.00001). Active treatment favored prevention of mania over depression. The key limitations were "responder-enriched" design in most trials and high outcomes heterogeneity. PROSPERO registration number is CRD42020162663.

Lamotrigine in the maintenance treatment of bipolar disorder

BACKGROUND

Bipolar disorder is a chronic mental disorder with repetitive mania/hypomania as well as depressive episodes, which eventually results in marked impairment in overall functioning and health-related quality of life.  A worldwide prevalence rate of 2.4% has been reported. The risk of suicide is higher in people with bipolar disorder than those with other mental disorders. Therefore, effective management of bipolar disorder in the maintenance period is warranted to minimize the risk of relapse or recurrence. Although lithium has been the standard treatment of bipolar disorder for many years, it is associated with adverse effects and teratogenicity. Lamotrigine is approved to be expected for prevention of recurrence for the maintenance treatment of bipolar disorder. In addition, lamotrigine is as effective as lithium. Therefore, we performed a systematic review to confirm the efficacy and safety of lamotrigine in the maintenance treatment of bipolar disorder.

OBJECTIVES

To assess the efficacy and tolerability of lamotrigine in the maintenance treatment of bipolar disorder.

SEARCH METHODS

We searched Ovid MEDLINE, Embase, PsycINFO, the Cochrane Common Mental Disorders Group's Specialized Register (CCMDCTR) and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to 21 May 2021. We also searched international trial registries and contacted experts in the field.

SELECTION CRITERIA

We included randomized controlled trials enrolling adults with bipolar disorder who were treated with lamotrigine, placebo or lithium.

DATA COLLECTION AND ANALYSIS

Two reviews authors independently checked the eligibility of studies and extracted data using a standardized form. Data extracted included study characteristics, participant characteristics, intervention details, settings, and outcome measures in the term of efficacy and tolerability. Study information were then entered into RevMan web.

MAIN RESULTS

We included 11 studies with a total of 2314 participants in this review; 1146 were randomized to lamotrigine, 869 were randomized to placebo and, 299 to lithium. We rated all studies as having an unclear risk of bias in at least one domain of Cochrane's tool for assessing risk of bias, with the most commonly observed weakness being selection bias (random sequence generation and allocation concealment). We judged five studies to be at a high risk of detection bias (blinding of outcome assessment). These potential biases pose as major threat to the validity of the included studies in this review. Outcomes of efficacy showed a possible advantage of lamotrigine over placebo. The estimated risk ratio (RR) for recurrence of manic symptom at one year as measured by the Young Mania Rating Scale (YMRS) was 0.67, (95% confidence interval (CI) 0.51 to 0.87; 3 studies, 663 participants; low-certainty evidence) in favor of lamotrigine. The RR of clinical worsening with the need for additional psychotropic treatment (RR 0.82, 95% CI 0.70 to 0.98; 4 studies, 756 participants) based on moderate-certainty evidence. The possible benefits of lamotrigine were also seen for the outcome of treatment withdrawal due to any reason at 6-12 months after treatment (RR 0.88, 95% CI 0.78 to 0.99; 4 studies, 700 participants; moderate-certainty evidence). Regarding tolerability, our analyses showed that the incidence rates of adverse effects were similar between the lamotrigine group and the placebo group (short-term effect: RR 1.07, 95% CI 0.81 to 1.42; 5 studies, 1138 participants; very low-certainty evidence; long-term effect: RR 0.97, 95% CI 0.77 to 1.23; 4 studies, 756 participants; moderate-certainty evidence). In the comparison between lamotrigine and lithium, efficacy was similar between groups except for recurrence of mania episode at one year. Recurrence of manic symptoms was higher in the lamotrigine group than that of the lithium group (RR 2.13, 95% CI 1.32 to 3.44; 3 studies, 602 participants; moderate-certainty evidence). Analysis of adverse effects at 6-12 months showed that a lower proportion of participants experienced at least one adverse effect when treated with lamotrigine compared to lithium (RR 0.70, 95% CI 0.51 to 0.96; 4 studies, 691 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Low- to moderate-certainty evidence collectively suggests that lamotrigine may be superior to placebo as a treatment modality for bipolar disorder. In comparison to lithium, people with bipolar disorder seem to tolerate lamotrigine better in the long run; however, the demonstrated efficacy in the maintenance of bipolar disorder was similar between the two groups.

Polypharmacy as maintenance treatment in bipolar illness: A systematic review

OBJECTIVES

Polypharmacy is common in maintenance treatment of bipolar illness, but proof of greater efficacy compared to monotherapy is assumed rather than well known. We systematically reviewed the evidence from the literature to provide recommendations for clinical management and future research.

METHOD

A systematic review was conducted on the use of polypharmacy in bipolar prophylaxis. Relevant papers published in English through 31 December 2019 were identified searching the electronic databases MEDLINE, Embase, PsycINFO, and the Cochrane Library.

RESULTS

Twelve studies matched inclusion criteria, including 10 randomized controlled trials (RCTs). The best drug combination in prevention is represented by lithium + valproic acid which showed a significant effect on time to mood relapses (HR = 0.57) compared to valproic acid monotherapy, especially for manic episodes (HR = 0.51). The effect was significant in terms of time to new drug treatment (HR = 0.51) and time to hospitalization (HR = 0.57). A significant reduction in the frequency of mood relapses was also reported for lithium + valproic acid vs. lithium monotherapy (RR=0.12); however, the trial had a small sample size. Lamotrigine + valproic acid reported significant efficacy in prevention of depressive episodes compared to lamotrigine alone.

CONCLUSIONS

The literature to support a generally greater efficacy with polypharmacy in bipolar illness is scant and heterogeneous. Within that limited evidence base, the best drug combination in bipolar prevention is represented by lithium + valproic acid for manic, but not depressive episodes. Clinical practice should focus more on adequate monotherapy before considering polypharmacy.

Mood stabilizers and/or antipsychotics for bipolar disorder in the maintenance phase: a systematic review and network meta-analysis of randomized controlled trials

We searched Embase, PubMed, and CENTRAL from inception until 22 May 2020 to investigate which antipsychotics and/or mood stabilizers are better for patients with bipolar disorder in the maintenance phase. We performed two categorical network meta-analyses. The first included monotherapy studies and studies in which the two drugs used were specified (i.e., aripiprazole, aripiprazole once monthly, aripiprazole+lamotrigine, aripiprazole+valproate, asenapine, carbamazepine, lamotrigine, lamotrigine+valproate, lithium, lithium+oxcarbazepine, lithium+valproate, olanzapine, paliperidone, quetiapine, risperidone long-acting injection, valproate, and placebo). The second included studies on second-generation antipsychotic combination therapies (SGAs) (i.e., aripiprazole, lurasidone, olanzapine, quetiapine, and ziprasidone) with lithium or valproate (LIT/VAL) compared with placebo with LIT/VAL. Outcomes were recurrence/relapse rate of any mood episode (RR-any, primary), depressive episode (RR-dep) and manic/hypomanic/mixed episode (RR-mania), discontinuation, mortality, and individual adverse events. Risk ratios and 95% credible interval were calculated. Forty-one randomized controlled trials were identified (n = 9821; mean study duration, 70.5 ± 36.6 weeks; percent female, 54.1%; mean age, 40.7 years). All active treatments other than carbamazepine, lamotrigine+valproate (no data) and paliperidone outperformed the placebo for RR-any. Aripiprazole+valproate, lamotrigine, lamotrigine+valproate, lithium, olanzapine, and quetiapine outperformed placebo for RR-dep. All active treatments, other than aripiprazole+valproate, carbamazepine, lamotrigine, and lamotrigine+valproate, outperformed placebo for RR-mania. Asenapine, lithium, olanzapine, quetiapine, and valproate outperformed placebo for all-cause discontinuation. All SGAs+LIT/VALs other than olanzapine+LIT/VAL outperformed placebo+LIT/VAL for RR-any. Lurasidone+LIT/VAL and quetiapine+LIT/VAL outperformed placebo+LIT/VAL for RR-dep. Aripiprazole+LIT/VAL and quetiapine+LIT/VAL outperformed placebo+LIT/VAL for RR-mania. Lurasidone+LIT/VAL and quetiapine+LIT/VAL outperformed placebo+LIT/VAL for all-cause discontinuation. Treatment efficacy, tolerability, and safety profiles differed among treatments.

Canadian Network for Mood and Anxiety Treatments (CANMAT) and International Society for Bipolar Disorders (ISBD) 2018 guidelines for the management of patients with bipolar disorder

The Canadian Network for Mood and Anxiety Treatments (CANMAT) previously published treatment guidelines for bipolar disorder in 2005, along with international commentaries and subsequent updates in 2007, 2009, and 2013. The last two updates were published in collaboration with the International Society for Bipolar Disorders (ISBD). These 2018 CANMAT and ISBD Bipolar Treatment Guidelines represent the significant advances in the field since the last full edition was published in 2005, including updates to diagnosis and management as well as new research into pharmacological and psychological treatments. These advances have been translated into clear and easy to use recommendations for first, second, and third- line treatments, with consideration given to levels of evidence for efficacy, clinical support based on experience, and consensus ratings of safety, tolerability, and treatment-emergent switch risk. New to these guidelines, hierarchical rankings were created for first and second- line treatments recommended for acute mania, acute depression, and maintenance treatment in bipolar I disorder. Created by considering the impact of each treatment across all phases of illness, this hierarchy will further assist clinicians in making evidence-based treatment decisions. Lithium, quetiapine, divalproex, asenapine, aripiprazole, paliperidone, risperidone, and cariprazine alone or in combination are recommended as first-line treatments for acute mania. First-line options for bipolar I depression include quetiapine, lurasidone plus lithium or divalproex, lithium, lamotrigine, lurasidone, or adjunctive lamotrigine. While medications that have been shown to be effective for the acute phase should generally be continued for the maintenance phase in bipolar I disorder, there are some exceptions (such as with antidepressants); and available data suggest that lithium, quetiapine, divalproex, lamotrigine, asenapine, and aripiprazole monotherapy or combination treatments should be considered first-line for those initiating or switching treatment during the maintenance phase. In addition to addressing issues in bipolar I disorder, these guidelines also provide an overview of, and recommendations for, clinical management of bipolar II disorder, as well as advice on specific populations, such as women at various stages of the reproductive cycle, children and adolescents, and older adults. There are also discussions on the impact of specific psychiatric and medical comorbidities such as substance use, anxiety, and metabolic disorders. Finally, an overview of issues related to safety and monitoring is provided. The CANMAT and ISBD groups hope that these guidelines become a valuable tool for practitioners across the globe.

The International College of Neuro-Psychopharmacology (CINP) Treatment Guidelines for Bipolar Disorder in Adults (CINP-BD-2017), Part 2: Review, Grading of the Evidence, and a Precise Algorithm

Background

The current paper includes a systematic search of the literature, a detailed presentation of the results, and a grading of treatment options in terms of efficacy and tolerability/safety.

Material and Methods

The PRISMA method was used in the literature search with the combination of the words 'bipolar,' 'manic,' 'mania,' 'manic depression,' and 'manic depressive' with 'randomized,' and 'algorithms' with 'mania,' 'manic,' 'bipolar,' 'manic-depressive,' or 'manic depression.' Relevant web pages and review articles were also reviewed.

Results

The current report is based on the analysis of 57 guideline papers and 531 published papers related to RCTs, reviews, posthoc, or meta-analysis papers to March 25, 2016. The specific treatment options for acute mania, mixed episodes, acute bipolar depression, maintenance phase, psychotic and mixed features, anxiety, and rapid cycling were evaluated with regards to efficacy. Existing treatment guidelines were also reviewed. Finally, Tables reflecting efficacy and recommendation levels were created that led to the development of a precise algorithm that still has to prove its feasibility in everyday clinical practice.

Conclusions

A systematic literature search was conducted on the pharmacological treatment of bipolar disorder to identify all relevant random controlled trials pertaining to all aspects of bipolar disorder and graded the data according to a predetermined method to develop a precise treatment algorithm for management of various phases of bipolar disorder. It is important to note that the some of the recommendations in the treatment algorithm were based on the secondary outcome data from posthoc analyses.

The 'disconnect' between initial judgments of lamotrigine vs. its real-world effectiveness in managing bipolar disorder. A tale with wider ramifications

OBJECTIVE

To detail the disconnect between the quantified efficacy of the mood stabilizer lamotrigine in its registration controlled trials and its later judged clinical effectiveness and consider some determinants of disconnects between some efficacy trial findings and 'real-world' clinical effectiveness judgments.

METHOD

Published articles considering lamotrigine as a treatment for the bipolar I or II disorders were selected for review. While randomized controlled trials were weighted, we also consider open trials and effectiveness observations from clinician researchers and demonstrate that lamotrigine has been quite variably judged over time.

RESULTS

We suggest that the early trials evaluating lamotrigine for acute bipolar disorder depression focused on a suboptimal clinical target, and in so doing, ensured less lamotrigine efficacy compared with trials of bipolar disorder preventative treatment. Moreover, a number of additional methodological limitations compromised analyses. We also detail variable reporting of actual study results. The initial sharp disconnect (between efficacy and effectiveness judgments) has narrowed as lamotrigine has been evaluated and progressively taken up as a maintenance mood stabilizer.

CONCLUSION

The lamotrigine disconnect story provides a number of salutary lessons that are salient to evaluating the effectiveness and ecological niche of any psychotropic medication. The lamotrigine story presented here argues strongly for the wisdom of encouraging an iterative process between efficacy studies and clinical observation.

The use of antidepressants in bipolar disorder patients with depression

INTRODUCTION

The proportion of time that bipolar patients experience depressive symptoms and clinical states, with associated psychosocial impairment and elevated risk of suicide, is significantly greater than the time spent in manic/hypomanic forms of bipolar disorders. Yet, manic states and symptoms have been the focus and interest of most clinical research over the past quarter century. Not a single antidepressant approved for treatment of major depressive disorder, as monotherapy, has received regulatory approval for treatment of bipolar depression as monotherapy, despite their common use in bipolar depression.

AREAS COVERED

We reviewed randomized studies, particularly ones initially intended for registration purposes, and systematic treatment guidelines, in development of this guide to treatment decision and implementation of interventions for depression in bipolar disorders.

EXPERT OPINION

The Expert Opinion section emphasizes strategies, not individual agents. The efficacious performance of mood stabilizers and second-generation antipsychotics as a component of the strategy is strongly supported by published studies. However, this section relies largely on secondary publications and our combined clinical experience, as few randomized, blinded studies have had, as their focus, the comparison of combined regimens for depression. This article summarizes the design features and results of studies dealing with depressive features and intervention strategies for bipolar disorders. The emphasis of the recommendations is on pragmatic treatment decisions that clinicians can make to enhance the probability of both short and long term benefits for patients.

Treatment implications of predominant polarity and the polarity index: a comprehensive review

BACKGROUND

Bipolar disorder (BD) is a serious and recurring condition that affects approximately 2.4% of the global population. About half of BD sufferers have an illness course characterized by either a manic or a depressive predominance. This predominant polarity in BD may be differentially associated with several clinical correlates. The concept of a polarity index (PI) has been recently proposed as an index of the antimanic versus antidepressive efficacy of various maintenance treatments for BD. Notwithstanding its potential clinical utility, predominant polarity was not included in the DSM-5 as a BD course specifier.

METHODS

Here we searched computerized databases for original clinical studies on the role of predominant polarity for selection of and response to pharmacological treatments for BD. Furthermore, we systematically searched the Pubmed database for maintenance randomized controlled trials (RCTs) for BD to determine the PI of the various pharmacological agents for BD.

RESULTS

We found support from naturalistic studies that bipolar patients with a predominantly depressive polarity are more likely to be treated with an antidepressive stabilization package, while BD patients with a manic-predominant polarity are more frequently treated with an antimanic stabilization package. Furthermore, predominantly manic BD patients received therapeutic regimens with a higher mean PI. The calculated PI varied from 0.4 (for lamotrigine) to 12.1 (for aripiprazole).

CONCLUSIONS

This review supports the clinical relevance of predominant polarity as a course specifier for BD. Future studies should investigate the role of baseline, predominant polarity as an outcome predictor of BD maintenance RCTs.

Safety and tolerability of anticonvulsant medication in bipolar disorder

INTRODUCTION

Anticonvulsants (AC) are widely used and recommended as a treatment option in different phases of bipolar disorder (BD). In contrast to ample evidence for efficacy in acute mania, there is generally less unambiguous evidence for maintenance treatment or bipolar depression, and data on long-term tolerability in BD are sparse, although this varies greatly between different compounds. This review summarizes the clinically relevant tolerability and safety profile of ACs commonly used for the treatment of BD based on findings from randomized controlled trials (RCT).

AREAS COVERED

Systematic search of the English literature between January 1991 and May 2015 revealed a total of nine RCTs investigating valproate, five RCTs with carbamazepine and 8 with lamotrigine For these ACs we found information on side effect profiles for both acute and maintenance RCTs, albeit of varying quality, whereas for topiramate (five RCTs), gabapentin and esclicarbazepine acetate (one RCT each) only acute treatment RCTs have been published. Descriptive side effect profiles from open-label studies exist for several other ACs rarely used in BD, and are included in this review as a brief narrative chapter.

EXPERT OPINION

Whereas both valproate and carbamazepine are associated with, in part, severe adverse events, lamotrigine emerges as a relatively safe and well tolerated treatment option, especially in maintenance treatment and prevention of depressive relapse in BD. Lack of proven efficacy and side effect profile of other, less rigorously studied ACs restricts their use only to very selected BD cases.

Clinical implications of predominant polarity and the polarity index in bipolar disorder: a naturalistic study

OBJECTIVE

Predominant polarity (PP) is an important variable in maintenance treatment of bipolar disorder (BD). This study aimed at determining the role of polarity index (PI), a metric indicating antimanic versus antidepressive prophylactic potential of drugs, in clinical decision-making.

METHOD

Two hundred and fifty-seven of 604 (43%) of patients with BD-I or II fulfilled criteria for manic (MPP) or depressive PP (DPP). The PI, representing the ratio of number needed to treat (NNT) for depression prevention to NNT for mania prevention, was calculated for patients' current treatment. MPP and DPP groups were compared regarding sociodemographic, clinical and therapeutic characteristics.

RESULTS

One hundred and forty-three patients (55.6%) fulfilled criteria for DPP and 114 (44.4%) for MPP. Total PI, Antipsychotics' PI, and mood stabilizers PI were higher, indicating a stronger antimanic action, in MPP. MPP presented higher prevalence of BD-I, male gender, younger age, age at onset and at first hospitalization, more hospitalizations, primary substance misuse, and psychotic symptoms. DP correlated with BD-II, depressive onset, primary life events, melancholia, and suicide attempts.

CONCLUSION

The results confirm the usefulness of the PI. In this large sample, clinical differences among these groups justify differential treatment approach. The PI appears to be a useful operationalization of what clinicians do for maintenance therapy in BD.

Valproic acid, valproate and divalproex in the maintenance treatment of bipolar disorder

BACKGROUND

Bipolar disorder is a recurrent illness that is amongst the top 30 causes of disability worldwide and is associated with significant healthcare costs. In the past, emphasis was placed solely on the treatment of acute episodes of bipolar disorder; recently, the importance of episode prevention and of minimisation of iatrogenicity has been recognised. For many years, lithium was the only mood stabiliser in common use, and it remains an agent of first choice in the preventative treatment of bipolar disorder. However, an estimated 20% to 40% of patients may not respond adequately to lithium. Valproate is an anticonvulsant drug that has been shown to be effective in acute mania and is frequently used in maintenance treatment of bipolar disorder. When the acceptability of long-term treatment is considered, together with efficacy, the adverse event profile of a medication is also important. This is an update of a Cochrane review first published in 2001 and last updated in 2009.

OBJECTIVES

1. To determine the efficacy of valproate continuation and maintenance treatment:a) in preventing or attenuating manic, depressive and mixed episodes of bipolar disorder;b) in preventing or attenuating episodes of bipolar disorder in patients with rapid cycling disorder; and; c) in improving patients' general health and social functioning, as measured by global clinical impression, employment and marital stability.2. To review the acceptability to patients of long-term valproate treatment, as measured by numbers of dropouts and reasons for dropping out, by compliance and by reference to patients' expressed views regarding treatment.3. To investigate the adverse effects of valproate treatment (including general prevalence of side effects) and overall mortality rates.

SEARCH METHODS

Search of the Cochrane Register of Controlled Trials and the Cochrane Depression, Anxiety and Neurosis Group Register (CCDANCTR) (to January 2013), which includes relevant randomised controlled trials from the following bibliographic databases: The Cochrane Library (all years), EMBASE, (1974 to date), MEDLINE (1950 to date) and PsycINFO (1967 to date). No language restrictions were applied. Reference lists of relevant papers and previous systematic reviews were handsearched. Pharmaceutical companies marketing valproate and experts in this field were contacted for supplemental data.

SELECTION CRITERIA

Randomised controlled trials allocating participants with bipolar disorder to long-term treatment with valproate or any other mood stabiliser, or antipsychotic drugs, or placebo. Maintenance treatment was defined as treatment instituted specifically or mainly to prevent further episodes of illness.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data. A double-entry procedure was employed by two review authors. Information extracted included study characteristics, participant characteristics, intervention details and outcome measures in terms of efficacy, acceptability and tolerability. For dichotomous data, risk ratios were calculated with 95% confidence intervals (CIs). For statistically significant results, we calculated the number needed to treat for an additional beneficial outcome (NNTB) and the number needed to treat for an additional harmful outcome (NNTH). For continuous data, mean differences (MDs) or standardised mean differences (SMDs) were calculated along with 95% CIs. MDs were used when the same scale was used to measure an outcome; SMDs were employed when different scales were used to measure the same outcome. The primary analysis used a fixed-effect model. Binary outcomes were calculated on a strict intention-to-treat (ITT) basis; dropouts were included in this analysis. When data were missing and the method of "last observation carried forward" (LOCF) had been used to do an ITT analysis, then the LOCF data were used.

MAIN RESULTS

Six randomised controlled trials (overall 876 participants) lasting 6 to 24 months were included. Two studies (overall 312 participants) compared valproate with placebo, four studies (overall 618 participants) valproate with lithium, one study (overall 23 participants) valproate with olanzapine and one study (overall 220 participants) valproate with the combination of valproate plus lithium. In terms of study quality, most studies reported the methods used to generate random sequence; however, only one study reported enough details on allocation concealment. Four of six included studies described their design as "double blind", but only two trials reported full details about blinding. Valproate was more effective than placebo in preventing study withdrawal due to any mood episode (RR 0.68, 95% CI 0.49 to 0.93; NNTB 8), but no difference in efficacy was found between valproate and lithium (RR 1.02, 95% CI 0.87 to 1.20). Valproate was associated with fewer participants dropping out of treatment for any cause when compared with placebo or lithium (RR 0.82, 95% CI 0.71 to 0.95 and RR 0.87, 95% CI 0.77 to 0.98, respectively). However, combination therapy with lithium plus valproate was more likely to prevent relapse than was monotherapy with valproate (RR 0.78, 95% CI 0.63 to 0.96). Significant differences in adverse event frequencies were found, and lithium was associated with more frequent diarrhoea, polyuria, increased thirst and enuresis, whereas valproate was associated with increased sedation and infection.

AUTHORS' CONCLUSIONS

Limited evidence supports the efficacy of valproate in the long-term treatment of bipolar disorder. Clinicians and patients should consider acceptability and tolerability profile when choosing between lithium and valproate-their combination or other agents-as long-term treatment for bipolar disorder.

Valproate as a risk factor for lamotrigine discontinuation

BACKGROUND

Although lamotrigine may be useful for treating bipolar depressive patients, some lamotrigine-associated adverse effects may prevent the continuation of treatment. The purpose of the present study was to identify risk factors for lamotrigine discontinuation after adjustment for several potential interactive factors.

METHODS

We examined tolerability in those who discontinued lamotrigine within 2 months of treatment and those who maintained lamotrigine for more than 2 months. Groups were examined separately because 6-8 weeks are necessary to titrate dose and drug eruptions can often occur within 2 months of treatment commencement.

RESULTS

Multiple regression analysis revealed that valproate combination was positively and significantly associated with lamotrigine discontinuation after adjustment for other factors.

LIMITATIONS

The limitations of the present study were retrospective observation and a relatively small number of subjects.

CONCLUSIONS

The present findings reconfirm that lamotrigine and valproate combination treatment may prevent the continuation of lamotrigine in some patients.