Lamotrigine augmentation in unipolar depression

Augmentative Pharmacological Strategies in Treatment-Resistant Major Depression: A Comprehensive Review

Treatment resistant depression (TRD) is associated with poor outcomes, but a consensus is lacking in the literature regarding which compound represents the best pharmacological augmentation strategy to antidepressants (AD). In the present review, we identify the available literature regarding the pharmacological augmentation to AD in TRD. Research in the main psychiatric databases was performed (PubMed, ISI Web of Knowledge, PsychInfo). Only original articles in English with the main topic being pharmacological augmentation in TRD and presenting a precise definition of TRD were included. Aripiprazole and lithium were the most investigated molecules, and aripiprazole presented the strongest evidence of efficacy. Moreover, olanzapine, quetiapine, cariprazine, risperidone, and ziprasidone showed positive results but to a lesser extent. Brexpiprazole and intranasal esketamine need further study in real-world practice. Intravenous ketamine presented an evincible AD effect in the short-term. The efficacy of adjunctive ADs, antiepileptic drugs, psychostimulants, pramipexole, ropinirole, acetyl-salicylic acid, metyrapone, reserpine, testosterone, T3/T4, naltrexone, SAMe, and zinc cannot be precisely estimated in light of the limited available data. Studies on lamotrigine and pindolol reported negative results. According to our results, aripiprazole and lithium may be considered by clinicians as potential effective augmentative strategies in TRD, although the data regarding lithium are somewhat controversial. Reliable conclusions about the other molecules cannot be drawn. Further controlled comparative studies, standardized in terms of design, doses, and duration of the augmentative treatments, are needed to formulate definitive conclusions.

Antidepressant and pro-motivational effects of repeated lamotrigine treatment in a rat model of depressive symptoms

Background

Methods

Results

Limitations

Conclusions

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.

Pharmacological evidence for the involvement of the NMDA receptor and nitric oxide pathway in the antidepressant-like effect of lamotrigine in the mouse forced swimming test

Lamotrigine is an anticonvulsant agent that shows clinical antidepressant properties. The aim of the present study was to investigate the involvement of N-methyl-d-aspartate (NMDA) receptors and nitric oxide-cyclic guanosine monophosphate (NO-cGMP) synthesis in possible antidepressant-like effect of lamotrigine in forced swimming test (FST) in mice. Intraperitoneal administration of lamotrigine (10mg/kg) decreased the immobility time in the FST (P<0.01) without any effect on locomotor activity in the open-field test (OFT), while higher dose of lamotrigine (30mg/kg) reduced the immobility time in the FST (P<0.001) as well as the number of crossings in the OFT. Pretreatment of animals with NMDA (75mg/kg), l-arginine (750mg/kg, a substrate for nitric oxide synthase [NOS]) or sildenafil (5mg/kg, a phosphodiesterase [PDE] 5 inhibitor) reversed the antidepressant-like effect of lamotrigine (10mg/kg) in the FST. Injection of l-nitroarginine methyl ester (l-NAME, 10mg/kg, a non-specific NOS inhibitor), 7-nitroindazole (30mg/kg, a neuronal NOS inhibitor), methylene blue (20mg/kg, an inhibitor of both NOS and soluble guanylate cyclase [sGC]), or MK-801 (0.05mg/kg), ketamine (1mg/kg), and magnesium sulfate (10mg/kg) as NMDA receptor antagonists in combination with a sub-effective dose of lamotrigine (5mg/kg) diminished the immobility time of animals in the FST compared with either drug alone. None of the drugs produced significant effects on the locomotor activity in the OFT. Based on our findings, it is suggested that the antidepressant-like effect of lamotrigine might mediated through inhibition of either NMDA receptors or NO-cGMP synthesis.

A systematic review for the antidepressant effects of sleep deprivation with repetitive transcranial magnetic stimulation

BACKGROUND

Sleep deprivation (SD) and repetitive transcranial magnetic stimulation (rTMS) have been commonly used to treat depression. Recent studies suggest that co-therapy with rTMS and SD may produce better therapeutic effects than either therapy alone. Therefore, this study was to review the current findings to determine if rTMS can augment the therapeutic effects of SD on depression.

METHODS

Embase, JSTOR, Medline, PubMed, ScienceDirect, and the Cochrane Central Register of Controlled Trials were searched for clinical studies published between January 1985 and March 2015 using the search term "rTMS/repetitive transcranial magnetic stimulation AND sleep deprivation AND depress*". Only randomized and sham-controlled trials (RCTs) involving the combined use of rTMS and SD in depression patients were included in this systematic review. The scores of the Hamilton Rating Scale for Depression were extracted as primary outcome measures.

RESULTS

Three RCTs with 72 patients that met the inclusion criteria were included for the systematic review. One of the trials reported skewed data and was described alone. The other two studies, which involved 30 patients in the experimental group (SD + active rTMS) and 22 patients in the control group (SD + sham rTMS), reported normally distributed data. The primary outcome measures showed different results among the three publications: two of which showed great difference between the experimental and the control subjects, and the other one showed non-significant antidepressant effect of rTMS on SD. In addition, two of the included studies reported secondary outcome measures with Clinical Global Impression Rating Scale and a self-reported well-being scale which presented good improvement for the depressive patients in the experiment group when compared with the control. The follow-up assessments in two studies indicated maintained results with the immediate measurements.

CONCLUSIONS

From this study, an overview of the publications concerning the combined use of rTMS and SD is presented, which provides a direction for future research of therapies for depression. More studies are needed to confirm whether there is an augmentative antidepressant effect of rTMS on SD.

Management of bipolar depression with lamotrigine: an antiepileptic mood stabilizer

The efficacy of lamotrigine in the treatment of focal epilepsies have already been reported in several case reports and open studies, which is thought to act by inhibiting glutamate release through voltage-sensitive sodium channels blockade and neuronal membrane stabilization. However, recent findings have also illustrated the importance of lamotrigine in alleviating the depressive symptoms of bipolar disorder, without causing mood destabilization or precipitating mania. Currently, no mood stabilizers are available having equal efficacy in the treatment of both mania and depression, two of which forms the extreme sides of the bipolar disorder. Lamotrigine, a well established anticonvulsant has received regulatory approval for the treatment and prevention of bipolar depression in more than 30 countries worldwide. Lamotrigine, acts through several molecular targets and overcomes the major limitation of other conventional antidepressants by stabilizing mood from “below baseline” thereby preventing switches to mania or episode acceleration, thus being effective for bipolar I disorder. Recent studies have also suggested that these observations could also be extended to patients with bipolar II disorder. Thus, lamotrigine may supposedly fulfill the unmet requirement for an effective depression mood stabilizer.

A neurobiological hypothesis of treatment-resistant depression - mechanisms for selective serotonin reuptake inhibitor non-efficacy

First-line treatment of major depression includes administration of a selective serotonin reuptake inhibitor (SSRI), yet studies suggest that remission rates following two trials of an SSRI are <50%. The authors examine the putative biological substrates underlying "treatment resistant depression (TRD)" with the goal of elucidating novel rationales to treat TRD. We look at relevant articles from the preclinical and clinical literature combined with clinical exposure to TRD patients. A major focus was to outline pathophysiological mechanisms whereby the serotonin system becomes impervious to the desired enhancement of serotonin neurotransmission by SSRIs. A complementary focus was to dissect neurotransmitter systems, which serve to inhibit the dorsal raphe. We propose, based on a body of translational studies, TRD may not represent a simple serotonin deficit state but rather an excess of midbrain peri-raphe serotonin and subsequent deficit at key fronto-limbic projection sites, with ultimate compromise in serotonin-mediated neuroplasticity. Glutamate, serotonin, noradrenaline, and histamine are activated by stress and exert an inhibitory effect on serotonin outflow, in part by "flooding" 5-HT1A autoreceptors by serotonin itself. Certain factors putatively exacerbate this scenario - presence of the short arm of the serotonin transporter gene, early-life adversity and comorbid bipolar disorder - each of which has been associated with SSRI-treatment resistance. By utilizing an incremental approach, we provide a system for treating the TRD patient based on a strategy of rescuing serotonin neurotransmission from a state of SSRI-induced dorsal raphe stasis. This calls for "stacked" interventions, with an SSRI base, targeting, if necessary, the glutamatergic, serotonergic, noradrenergic, and histaminergic systems, thereby successively eliminating the inhibitory effects each are capable of exerting on serotonin neurons. Future studies are recommended to test this biologically based approach for treatment of TRD.

Lamotrigine in the treatment of unipolar depression with and without comorbidities: a literature review

To review the available data behind the use of lamotrigine in unipolar depression and common comorbid conditions. A PubMed based literature review was conducted using keywords related to lamotrigine, depression, anxiety, post traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), and personality disorders. A large number of trials using lamotrigine for unipolar depression and various comorbid conditions were reviewed. A major limitation behind the majority of studies was a limited course of the treatment phase. The most robust data was found among studies that followed patients for over 8 weeks, and used higher dosages. Patients with comorbid anxiety states appeared to benefit. Patients with borderline personality disorder also appeared to benefit. The benefits of lamotrigine in unipolar depression have been inconsistently noted in a number of studies. This is due in part to short treatment phases, atypical domains of benefit and different patient populations across studies. Patients with more treatment-resistance, comorbid anxiety and borderline personality disorder may be more able to benefit from lamotrigine.

Efficacy and safety of antidepressant augmentation with lamotrigine in patients with treatment-resistant depression: a randomized, placebo-controlled, double-blind study

OBJECTIVE

This study reports a clinical trial evaluating lamotrigine safety and efficacy as an antidepressant augmentation agent in treatment-resistant depression, therefore adding more empirical evidence to the limited number of studies on the use of lamotrigine.

METHOD

A double-blind pilot study was conducted between March 2004 and January 2006 with 34 nonbi-polar, nonpsychotic patients who had DSM-IV major depressive disorder and were resistant to at least 2 anti-depressants. The subjects were taking antidepressant therapy and were randomly assigned to receive placebo or lamotrigine as an adjunct therapy for 8 weeks. They were evaluated on a biweekly basis in order to assess the efficacy and the safety of the drug. Efficacy was measured with the Montgomery-Asberg Depression Rating Scale (MADRS) and the Clinical Global Impressions (CGI) scale. Response was defined as a decrease of at least 50% from baseline on the MADRS and a final score ≤ 2 on the CGI. Safety was assessed by keeping record of treatment-emergent adverse events.

RESULTS

The results of the adjunct treatment with lamotrigine did not reveal a significant difference according to the MADRS (p = .45). No differences between the 2 treatment groups were revealed by the repeated-measures analysis of variance or by the analysis based on the CGI (p = .45). More than 50% of the patients had been treated with at least 3 different anti-depressants. The most frequent adverse events were nausea, rash, and dyspepsia in the lamotrigine group and dizziness and headache in the placebo group.

CONCLUSIONS

In this study, although it was safe, lamotrigine was not found to be an efficient augmentation agent in treatment-resistant depression. Small sample size, higher chronicity, and refractoriness may be related to treatment failure.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00652171.

Lithium but not carbamazepine augments antidepressant efficacy of mirtazapine in unipolar depression: an open-label study

BACKGROUND

The purpose of the present open-label study was to investigate the antidepressant efficacy of lithium and carbamazepine as augmentation strategies in unipolar depressed inpatients.

METHOD

Forty-six patients suffering from unipolar depression (major depressive episode according to DSM-IV criteria) were pre-treated with mirtazapine for 2 weeks initially (week -2 to week 0). Thereafter, the patients received either continuation of mirtazapine monotherapy (n = 23), combination treatment with mirtazapine and lithium (n = 13), or combination therapy with mirtazapine and carbamazepine (n = 10) for further 3 weeks (week 0 to week 3). Severity of depression was estimated weekly using the 21-item version of the Hamilton Depression Rating Scale (21-HAMD). Response was defined by a reduction of at least 50% in the 21-HAMD sum score after 3 weeks of pharmacotherapy (week 0-3).

RESULTS

Additional administration of lithium, but not adjunctive carbamazepine significantly augmented the antidepressant efficacy of mirtazapine in the unipolar depressed patients. Moreover, carbamazepine but not lithium significantly lowered the serum concentrations of mirtazapine.

CONCLUSION

Whereas the clinical importance of anticonvulsants in the treatment of bipolar disorder is not in doubt, the therapeutic efficacy of antiepileptic drugs such as carbamazepine is obviously limited in the pharmacotherapy of unipolar depression.

Anticonvulsants in the treatment of major depressive disorder: an overview

Major depressive disorder (MDD) is highly prevalent, potentially disabling, and sometimes fatal. Antidepressants (ADs) have improved its treatment, but incomplete response, sustained morbidity, recurrences, agitation, substance abuse, excess medical mortality, and suicide remain unsolved problems among mood disorder patients. AD treatment itself sometimes induces adverse behavioral responses. Several anticonvulsants (ACs) used to treat bipolar disorder (BPD) might also be of value for MDD. Accordingly, we reviewed published reports on ACs for MDD, identifying studies by computerized searches. We excluded reports dealing only with BPD patients or with sedatives, classified trials by design quality, and evaluated treatment of acute episodes and recurrences of adult MDD. We found 36 reports involving 41 relevant trials of carbamazepine (12 trials), valproate (11), lamotrigine (9), gabapentin (3), topiramate (3), phenytoin (2), and tiagabine (1). They include 9 blinded, controlled trials (of 28-70 days), involving carbamazepine (3 trials), lamotrigine (3), phenytoin (2), or topiramate (1) as primary treatments (5) or AD adjuncts (4). Some of these trials, as well as 7 of lesser quality, suggest benefits of carbamazepine, lamotrigine, and valproate, mainly as adjuncts to ADs. Another 20 anecdotes or small trials further suggest that these ACs might be useful as AD adjuncts-specifically to treat irritability or agitation in MDD. Overall, these reports provide suggestive evidence of beneficial effects of carbamazepine, lamotrigine, and valproate that require further study, especially for long-term adjunctive use, particularly in patients with recurring MDD with prominent irritability or agitation.

Combined treatments for major depression

Major depression is a chronic disorder with a high morbidity and mortality. Approved treatment for major depression at present includes monotherapy with antidepressants of different pharmacologic classes. There is increasingly widespread use of two other options: augmentation, the addition to an antidepressant of a second compound that is not an antidepressant when used alone; and combination, which is the use of two antidepressants concurrently to enhance or accelerate response. This review focuses on the data available to support these various augmentation and combination treatments.

Lithium versus lamotrigine augmentation in treatment resistant unipolar depression: a randomized, open-label study

Treatment-resistant depression affects up to 70% of patients. In our 8-week, randomized, open-label, prospective study of 34 treatment-resistant depression patients lamotrigine-add-on was compared with lithium-augmentation. Both treatments resulted in clinically significant reduction in Hamilton rating scale for depression score: mean Hamilton rating scale for depression-score declined from 22.7 (SD 3.9) to 11.7 (SD 4.2) in the lamotrigine group and from 21.5 (SD 3.8) to 13.3 (SD 5.7) in the lithium (Li) group. No significant differences were seen in Hamilton rating scale for depression scores between treatment groups at baseline (P=0.82) and after 8 weeks (P=0.11). Twenty-three percent of the lamotrigine group (n=4) and 18% (n=3) of the Li group achieved remission, 53% of the lamotrigine group (n=9) responded to treatment vs. 41% in the Li group (n=7) and 47% of the lamotrigine group (n=8) vs. 35% of the Li group (n=6) showed at least a partial response. Lamotrigine-augmentation was well tolerated. In conclusion, this study demonstrated that the add-on of lamotrigine to antidepressive medication revealed comparable results in most outcome measures as a lithium augmentation. Owing to small sample size no conclusions regarding similar efficacy can be drawn from our data. Larger trials that should include a placebo arm are needed to further investigate lamotriginés role in treatment-resistant depression.

Antidepressant-like effect of lamotrigine in the mouse forced swimming test: evidence for the involvement of the noradrenergic system

Lamotrigine is an anticonvulsant drug that is also effective in the treatment of mood disorders, especially bipolar disorder. However, few studies have been conducted in animal models of depression to evaluate its mechanism of action. The present study investigated the effect of lamotrigine in the forced swimming test in mice and the involvement of the noradrenergic system in this effect. Lamotrigine (20-30 mg/kg, i.p.) decreased the immobility time in the forced swimming test and the number of crossings in the open-field test. In addition, the pretreatment of mice with the inhibitor of the enzyme tyrosine hydroxylase, alpha-methyl-p-tyrosine (100 or 250 mg/kg), prevented the antidepressant-like effect of lamotrigine (30 mg/kg, i.p.) in the forced swimming test. Besides that, the pretreatment of mice with prazosin (1 mg/kg, i.p., an alpha1-adrenoceptor antagonist) or yohimbine (1 mg/kg, i.p., an alpha2-adrenoceptor antagonist) also prevented the anti-immobility effect of lamotrigine (30 mg/kg, i.p.). Moreover, the administration of subeffective doses of phenylephrine (5 mg/kg, i.p., an alpha1-adrenoceptor agonist) or clonidine (0.06 mg/kg, i.p., an alpha2-adrenoceptor agonist) was able to potentiate the action of a subeffective dose of lamotrigine (10 mg/kg, i.p.) in the forced swimming test. Thus, the present study suggests that the antidepressant-like effect of lamotrigine in the forced swimming test is related to the noradrenergic system, likely due to an activation of alpha1- and alpha2-postsynaptic adrenoceptors.

Lamotrigine adjunctive treatment in resistant unipolar depression: an open, descriptive study

Adjunctive treatment of lamotrigine compared to other antidepressants in the treatment of partially responsive, poorly functioning patients with unipolar depression was assessed. Fourteen consenting patients with confirmed DSM-IV-R diagnosis of unipolar depression were identified as treatment resistant. All patients failed at least two 8-week treatment trials with antidepressants. All were treated with lamotrigine as an adjunct to other antidepressants for at least 6 months. The primary effectiveness measure was the Clinical Global Impression Severity subscale (CGI-S). Other scales included the Montgomery-Asberg Depression Scale (MADRS) and the Global Assessment of Functioning Scale (GAF). Monitoring for skin rashes, headache, dizziness, somnolence, and gastrointestinal disturbances was carried out to assess for adverse events. Baseline measures prior to adding lamotrigine were compared to those at 8 weeks and 6 months with adjunctive treatment. Twelve patients of the total (n=14) completed the trial, and two discontinued treatment. There was significant, rapid, and robust resolution in symptoms in all effectiveness measures, including the core symptoms of depression, as shown by the changes from baseline in CGI-S, and MADRS at 8 weeks. Social and occupational functioning was significantly improved at 6 months. Eight patients returned to gainful employment or started schooling. Patients tolerated the adjunctive lamotrigine treatment well. Lamotrigine may have antidepressant properties in patients with unipolar depression and may have an earlier onset of action when given in combination with antidepressants.

Anticonvulsants in sports: ethical considerations

OBJECTIVE

Antidoping codes in sport are intended to deter and sanction athletes using performance-enhancing agents while promoting an even playing field for all competitors. Although the World Anti-Doping Code (WADC) permits anticonvulsants in general, harmonization of antidoping permits an international sport federation (IF) to prohibit specific medications within that IF. The anticonvulsants levetiracetam, tiagabine, and lamotrigine may pose ethical dilemmas and could be considered violations of antidoping codes.

METHOD

This study is a literature review with analysis.

RESULTS

Lamotrigine, with antiglutamatergic and sodium channel properties, is FDA-approved for maintenance treatment of bipolar disorder, in addition to its use in the treatment of major depression, anxiety disorders, and schizophrenia. Tiagabine, a selective GABA reuptake inhibitor, has mood-stabilizing and anxiolytic properties. Levetiracetam, whose unique mechanism involves the modulators beta-carboline and zinc, has anxiolytic and mood-stabilizing properties. Anxiolytics, antidepressants, and antipsychotics are banned in archery; under strict liability, all three anticonvulsants violate WADC/IF for that specific sport and could result in disqualification unless therapeutic use exemptions (TUEs) are obtained. Ethical issues regarding the use of anticonvulsants by athletes and the need to obtain TUEs are addressed.

CONCLUSION

The WADC with harmonized IF policies are meant to prevent doping by athletes, but not appropriate medical treatment. When anticonvulsants have other psychotropic properties, ethical issues arise. Athletes should list all medications taken with diagnoses, obtain TUEs as indicated, and contact the appropriate IF or Olympic organization to determine the status of the proposed medication (banned, restricted, nonbanned). Further, clinicians should be knowledgeable regarding these issues when treating athletes.

A Critical Overview of the Pharmacologic Management of Treatment-Resistant Depression

Major depressive disorder is a frequent, serious disorder that usually responds partially to treatment and leaves many patients with treatment resistance. This article reviews and critically evaluates the evidence for the management of treatment-resistant depression and examines pharmacologic approaches to alleviate the suffering of patients who benefit insufficiently from initial treatment.

Lamotrigine in patients with epilepsy and comorbid depressive symptoms

PURPOSE

This open-label study evaluated the antidepressant qualities of lamotrigine (LTG) in people with epilepsy.

METHODS

Eligible patients exhibited low to moderate depressive symptoms and required a change in antiepileptic drug (AED) therapy, but were excluded if they had a major depressive disorder (MDD). Lamotrigine was added onto a stable AED regimen, and self-report instruments were administered to evaluate changes in mood states. Evaluations were conducted at baseline, at the end of 19 weeks of adjunctive treatment, and 36 weeks following conversion to monotherapy.

RESULTS

One hundred and fifty-eight patients with epilepsy participated; 96 patients completed adjunctive treatment, and 66 patients completed monotherapy. Intent-to-treat analyses for all instruments showed improvement in depression scores after adjunctive LTG treatment. Improvement was maintained for those converted to monotherapy.

CONCLUSIONS

These data suggest that LTG may have antidepressant activity for patients with epilepsy and comorbid low to moderate depressive symptoms, and warrant a randomized controlled trial for validation.

Treatment-resistant depression in adolescents: recognition and management

Approximately 20% of adolescents experience at least one depressive episode by the time they enter their adult years. For most adolescents, depression, although serious, either remits spontaneously or responds to treatment. For a smaller but significant proportion of adolescents, however, depression can be long-lasting and relatively unresponsive to initial treatment. In this article the authors provide an operational definition of treatment-resistant depression, identify factors associated with treatment nonresponse, describe an approach to the management of treatment-resistant depression, and advance suggestions for promising avenues of research.

Potentiation strategies for treatment-resistant depression

OBJECTIVE

To review the pharmacological basis of antidepressant potentiation in combination therapy and the clinical evidence for its efficacy.

METHOD

Literature searches were undertaken and the results reviewed.

RESULTS

Treatment-resistant depression is common (15-30%). Various strategies exist for dealing with resistant depression, including pharmacological potentiation, i.e. adding a treatment that itself does not have antidepressant actions but that enhances the efficacy of the original treatment. Lithium, triiodothyronine (T3) and buspirone are the best studied potentiating drugs, although other options include pindolol, dopaminergic agents, second-generation antipsychotics, psychostimulants, hormones and anticonvulsants.

CONCLUSION

Several pharmacological potentiation strategies exist. Whilst good evidence exists for lithium combined with antidepressants, although good results have also been reported with augmentation strategies involving T3 or buspirone.

Lamotrigine augmentation strategy for patients with treatment-resistant depression

OBJECTIVE

To investigate if lamotrigine added to an antidepressant regimen reduces the symptoms of major depression in treatment-resistant patients.

INTRODUCTION

Charts were retrospectively reviewed for 34 patients (36-63 years of age) with major depressive disorder who received lamotrigine augmentation to the antidepressant regimen for treatment-resistant depression (TRD). Data collection occurred at baseline and at an average of 30 (Time 2), 78 (Time 3), 167 (Time 6), and 356 days (Time 12), thereafter, using a "Medication Visit by MD" scale for collection of target symptom data at each timepoint.

RESULTS

Following the addition of lamotrigine to the antidepressant regimen (mean dose of 43, 63, and 113 mg/day for Time 3, Time 6, and Time 12, respectively), a statistically significant reduction of scores was shown as early as Time 2 for target symptoms of depressed mood, loss of interest, anxiety, irritability, (low) energy, and cognitive impairment. The difference from baseline remained statistically significant at Time 3, Time 6, and Time 12 (with the exception of irritability, which was not statistically significant at Time 6). "Patient's response" also reflected statistically significant improvement at each time period compared with baseline. The most common side effect reported and reason for discontinuation was tiredness.

DISCUSSION

Because TRD is a clinical condition that can present with severe and disabling symptoms, many clinicians are faced with an urgent need to find relief for their patients. Trying to achieve symptom improvement in a timely manner during a medication change can be challenging and difficult. This can be managed by an augmentation strategy using a psychotropic add-on to an existing medication regimen. Our results show the benefits of lamotrigine augmentation to an antidepressant regimen. Prospective, controlled clinical trials with larger sample size are needed to confirm our results.

CONCLUSION

In this retrospective chart review, augmentation with lamotrigine was a tolerable and efficacious strategy for treating patients with TRD.

Beyond monoamines: glutamatergic function in mood disorders

The monoamine theory has implicated abnormalities in serotonin and norepinephrine in the pathophysiology of major depression and bipolar illness and contributed greatly to our understanding of mood disorders and their treatment. Nevertheless, some limitations of this model still exist that require researchers and clinicians to seek further explanation and develop novel interventions that reach beyond the confines of the monoaminergic systems. Recent studies have provided strong evidence that glutamate and other amino acid neurotransmitters are involved in the pathophysiology and treatment of mood disorders. Studies employing in vivo magnetic resonance spectroscopy have revealed altered cortical glutamate levels in depressed subjects. Consistent with a model of excessive glutamate-induced excitation in mood disorders, several antiglutamatergic agents, such as riluzole and lamotrigine, have demonstrated potential antidepressant efficacy. Glial cell abnormalities commonly associated with mood disorders may at least partly account for the impairment in glutamate action since glial cells play a primary role in synaptic glutamate removal. A hypothetical model of altered glutamatergic function in mood disorders is proposed in conjunction with potential antidepressant mechanisms of antiglutamatergic agents. Further studies elucidating the role of the glutamatergic system in the pathophysiology of mood and anxiety disorders and studies exploring the efficacy and mechanism of action of antiglutamatergic agents in these disorders, are likely to provide new targets for the development of novel antidepressant agents.

Lamotrigine has an anxiolytic-like profile in the rat conditioned emotional response test of anxiety: a potential role for sodium channels?

RATIONALE

Many anticonvulsants are used in disorders other than epilepsy. For example, lamotrigine is reported to be effective in post-traumatic stress disorder and mania.

OBJECTIVE

We assessed the effects of the anticonvulsants lamotrigine, valproate and carbamazepine in an animal model of anxiety. We assessed a wide range of pharmacological tools to delineate the mechanism of lamotrigine's anxiolytic effect.

METHODS

We assessed these compounds in the rat conditioned emotional response (CER) test of anxiety.

RESULTS

Lamotrigine (30-80 mg/kg) dose-dependently and reproducibly engendered an anxiolytic response in this test, with similar efficacy to benzodiazepines. Carbamazepine (20-40 mg/kg) and riluzole (10 mg/kg), which block Na+ channels by a similar mechanism as lamotrigine, were also anxiolytic. By contrast, valproate (100-600 mg/kg) was inactive and appears to differ in its interaction with Na+ channels. The SSRI paroxetine, the GABA(A) receptor positive modulator propofol, the NMDA antagonists memantine and (+)MK-801, and the Ca2+ channel antagonist nifedipine were all inactive in the CER test, suggesting these mechanisms may not mediate the anxiolytic effect of lamotrigine. More directly, we showed that the anxiolytic effect of lamotrigine could be blocked by co-administering rats with the Na+ channel activator veratrine (0.1 mg/kg). By contrast, neither the Ca2+ channel agonist BAYK8644 (0.5 mg/kg) nor the 5-HT1A or 5-HT(1/2) antagonists WAY100635 (0.3 mg/kg) and metergoline (3 mg/kg), respectively, were able to block the effect.

CONCLUSION

Lamotrigine's anxiolytic effect in the CER test may be mediated via block of Na+ channels, and this may represent a target for the development of novel anxiolytics.

Lamotrigine for bipolar disorder: translating research into clinical practice

Lamotrigine (Lamictal, GlaxoSmithKline) is a recently developed anticonvulsant which has been investigated for efficacy in bipolar disorder. Increasing evidence indicates that it may have a different therapeutic profile than more established first-line mood stabilizers such as lithium and valproate. In particular, evidence from well-designed trials suggests efficacy for acute management and prophylaxis of bipolar depression but not mania. However, clinically relevant drug interactions and side effects can occur with lamotrigine, including benign to serious rash. The objectives of this drug profile are to review the basic chemical and pharmacological characteristics of lamotrigine, critically examine the growing body of research literature on its clinical use in the treatment of bipolar disorder, and review the safety and tolerability of lamotrigine as well as drug interactions relevant to clinical practice. Practical recommendations regarding titration and the management of rash are offered.

Lamotrigine in psychiatry: pharmacology and therapeutics

Following the introduction of lamotrigine in 1994 as a treatment for epilepsy in the United States, the drug has seen progressively greater application in psychiatry, particularly as a treatment for bipolar disorder. This review critically evaluates the support for lamotrigine use across a broad range of psychiatric disorders as well as discuss its pharmacology, side-effect profile, and interactions with other medications.