Lamotrigine: a review of its use in bipolar disorder

Lamotrigine (Lamictal), a phenyltriazine derivative, is a well established anticonvulsant agent that has shown efficacy in the prevention of mood episodes in adult patients with bipolar I disorder. The mechanism of action of the drug in patients with bipolar disorder may be related to the inhibition of sodium and calcium channels in presynaptic neurons and subsequent stabilisation of the neuronal membrane. Lamotrigine monotherapy significantly delayed time to intervention with additional pharmacotherapy or electroconvulsive therapy for any new mood episode (mania, hypomania, depression and mixed episodes), compared with placebo, in two large, randomised, double-blind trials of 18 months' duration. Additionally, lamotrigine was significantly superior to placebo at prolonging time to intervention for depression. These effects of lamotrigine were demonstrated in both recently manic/hypomanic and recently depressed patients. Lamotrigine showed efficacy in delaying manic/hypomanic episodes in pooled data only, although lithium was superior to lamotrigine on this measure. Two of four double-blind, short-term studies have shown lamotrigine to be more effective than placebo in the treatment of patients with treatment-refractory bipolar disorder or those with bipolar depression. Lamotrigine has not demonstrated efficacy in the treatment of acute mania.Lamotrigine was generally well tolerated in maintenance studies with the most common adverse events being headache, nausea, infection and insomnia. Incidences of diarrhoea and tremor were significantly lower in lamotrigine- than in lithium-treated patients. The incidence of serious rash with lamotrigine treatment was 0.1% in all studies of bipolar disorder and included one case of mild Stevens-Johnson syndrome. Lamotrigine did not appear to cause bodyweight gain. The dosage of lamotrigine is titrated over a 6-week period to 200 mg/day to minimise the incidence of serious rash. Adjustments to the initial and target dosages are required if coadministered with valproate semisodium or carbamazepine. CONCLUSION: Lamotrigine has been shown to be an effective maintenance therapy for patients with bipolar I disorder, significantly delaying time to intervention for any mood episode. Additionally, lamotrigine significantly delayed time to intervention for a depressive episode and showed limited efficacy in delaying time to intervention for a manic/hypomanic episode, compared with placebo. Although not approved for the short-term treatment of mood episodes, lamotrigine has shown efficacy in the acute treatment of patients with bipolar depression but has not demonstrated efficacy in the treatment of acute mania. Lamotrigine is generally well tolerated, does not appear to cause bodyweight gain and, unlike lithium, generally does not require monitoring of serum levels.     

Spotlight on lamotrigine in bipolar disorder

Lamotrigine (Lamictal), a phenyltriazine derivative, is a well established anticonvulsant agent that has shown efficacy in the prevention of mood episodes in adult patients with bipolar I disorder. The mechanism of action of the drug in patients with bipolar disorder may be related to the inhibition of sodium and calcium channels in presynaptic neurons and subsequent stabilisation of the neuronal membrane. Lamotrigine monotherapy significantly delayed time to intervention with additional pharmacotherapy or electroconvulsive therapy for any new mood episode (mania, hypomania, depression and mixed episodes), compared with placebo, in two large, randomised, double-blind trials of 18 months' duration. Additionally, lamotrigine was significantly superior to placebo at prolonging time to intervention for depression. These effects of lamotrigine were demonstrated in both recently manic/hypomanic and recently depressed patients. Lamotrigine showed efficacy in delaying manic/hypomanic episodes in pooled data only, although lithium was superior to lamotrigine on this measure. Two of four double-blind, short-term studies have shown lamotrigine to be more effective than placebo in the treatment of patients with treatment-refractory bipolar disorder or those with bipolar depression. Lamotrigine has not demonstrated efficacy in the treatment of acute mania. Lamotrigine was generally well tolerated in maintenance studies with the most common adverse events being headache, nausea, infection and insomnia. Incidences of diarrhoea and tremor were significantly lower in lamotrigine- than in lithium-treated patients. The incidence of serious rash with lamotrigine treatment was 0.1% in all studies of bipolar disorder and included one case of mild Stevens-Johnson syndrome. Lamotrigine did not appear to cause bodyweight gain. The dosage of lamotrigine is titrated over a 6-week period to 200 mg/day to minimise the incidence of serious rash. Adjustments to the initial and target dosages are required if coadministered with valproate semisodium or carbamazepine. CONCLUSION: Lamotrigine has been shown to be an effective maintenance therapy for patients with bipolar I disorder, significantly delaying time to intervention for any mood episode. Additionally, lamotrigine significantly delayed time to intervention for a depressive episode and showed limited efficacy in delaying time to intervention for a manic/hypomanic episode, compared with placebo. Although not approved for the short-term treatment of mood episodes, lamotrigine has shown efficacy in the acute treatment of patients with bipolar depression but has not demonstrated efficacy in the treatment of acute mania. Lamotrigine is generally well tolerated, does not appear to cause bodyweight gain and, unlike lithium, generally does not require monitoring of serum levels.     

Lamotrigine prevents ketamine but not amphetamine-induced deficits in prepulse inhibition in mice

Rationale Lamotrigine, a broad-spectrum anticonvulsant known to block brain sodium channels, is effective in the treatment of persons with bipolar disorder, perhaps by virtue of its ability to reduce glutamate release. Furthermore, lamotrigine decreases the perceptual abnormalities produced by the N-methyl-d-aspartate (NMDA) antagonist ketamine in humans, similar to the effects of the atypical antipsychotic clozapine. Acutely manic bipolar patients, like persons with schizophrenia, Tourette's, and obsessive compulsive disorder, exhibit decreases in sensorimotor gating, as measured by prepulse inhibition of the startle response (PPI). Objective We assessed the ability of lamotrigine to reduce the PPI–disruptive effects of ketamine and the dopaminergic agent amphetamine in two inbred mouse strains, C57BL/6J and 129SvPasIco. Methods Mice were tested in a standard PPI paradigm after administration of lamotrigine (0, 6.7, 13, or 27 mg/kg) or a combination of lamotrigine (27 mg/kg) and either d-amphetamine (10 mg/kg) or ketamine (100 mg/kg). Results In the 129SvPasIco mice, lamotrigine reversed the ketamine-induced PPI deficit, without altering PPI in control mice. In C57BL/6J mice, however, 27 mg/kg lamotrigine generally increased PPI in both control and ketamine-treated mice. Lamotrigine did not ameliorate the amphetamine-induced PPI deficit in either strain. Conclusions In conclusion, lamotrigine can increase PPI on its own and prevent ketamine-induced, but not amphetamine-induced, disruptions of PPI. These results suggest that lamotrigine may exert its effects on PPI through the glutamatergic system.     

The potential role of lamotrigine in schizophrenia

Rationale Atypical antipsychotic drugs are the drugs of choice for the treatment of schizophrenia. However, despite advances, no treatments have been established for patients who fail to improve with the most effective of these, clozapine. The inhibition of dopamine transmission through blockade of dopamine D2 receptors is considered to be essential for antipsychotic efficacy, but it is postulated that modulation of glutamate transmission may be equally important. In support of this, symptoms similar to schizophrenia can be induced in healthy volunteers using N-methyl-d-aspartate (NMDA) antagonist drugs that are also known to enhance glutamate transmission. Furthermore, lamotrigine, which can modulate glutamate release, may add to or synergise with atypical antipsychotic drugs, some of which may themselves modulate glutamate transmission. Objectives We examine the evidence for the efficacy of lamotrigine. We consider how this fits with a glutamate neuron dysregulation hypothesis of the disorder. We discuss mechanisms by which lamotrigine might influence neuronal activity and glutamate transmission, and possible ways in which the drug might interact with antipsychotic medications. Results Data from four clinical studies support the efficacy of adjunctive lamotrigine in the treatment of schizophrenia. In addition, and consistent with a glutamate neuron dysregulation hypothesis of schizophrenia, lamotrigine can prevent the psychotic symptoms or behavioural disruption induced by NMDA receptor antagonists in healthy volunteers or rodents. Conclusions The efficacy of lamotrigine is most likely explained within the framework of a glutamate neuron dysregulation hypothesis, and may arise primarily through the drugs ability to influence glutamate transmission and neural activity in the cortex. The drug is likely to act through inhibition of voltage-gated sodium channels, though other molecular interactions cannot be ruled out. Lamotrigine may add to or synergise with some atypical antipsychotic drugs acting on glutamate transmission; alternatively, they may act independently on glutamate and dopamine systems to bring about a combined therapeutic effect. We propose new strategies for the treatment of schizophrenia using a combination of anti-dopaminergic and anti-glutamatergic drugs.     

Safety and tolerability of lamotrigine for bipolar disorder.

Tolerability and safety are important considerations in optimising pharmacotherapy for bipolar disorder. This paper reviews the tolerability and safety of lamotrigine, an anticonvulsant recommended in the 2002 American Psychiatric Association guidelines as a first-line treatment for acute depression in bipolar disorder and one of several options for maintenance therapy. This paper reviews the tolerability and safety of lamotrigine using data available from a large programme of eight placebo-controlled clinical trials of lamotrigine enrolling a total of nearly 1800 patients with bipolar disorder. This review is the first to collate all the safety information from these clinical trials, including data from four unpublished studies. The results these trials in which 827 patients with bipolar disorder were given lamotrigine as monotherapy or adjunctive therapy for up to 18 months for a total of 280 patient-years of exposure demonstrated that lamotrigine is well-tolerated with an adverse-event profile generally comparable with that of placebo. The most common adverse event with lamotrigine was headache. Lamotrigine did not appear to destabilise mood and was not associated with sexual adverse effects, weight gain, or withdrawal symptoms. Few patients experienced serious adverse events with lamotrigine, and the incidence of withdrawals because of adverse events was low. Serious rash occurred rarely (0.1% incidence) in the clinical development programme including both controlled and uncontrolled clinical trials. These findings - considered in the context of data showing lamotrigine to be effective for bipolar depression - establish lamotrigine as a well-tolerated addition to the psychotropic armamentarium.     

Lamotrigine-induced obsessional symptoms in a patient with bipolar II disorder: a case report

Lamotrigine is an anticonvulsant that appears to have a mainly antidepressant effect and is indicated for the maintenance treatment of bipolar depression. Literature associated with obsessional symptoms related to lamotrigine treatment is limited. We report the emergence of obsessive symptoms during treatment with lamotrigine in a patient who subsequently experienced significant improvement after dose reduction and stopping of this medication. The obsessive symptoms associated with lamotrigine treatment were observed after the lamotrigine dose was increased to 100 mg/day. The possible mechanisms, including inhibition on the presynaptic release of glutamate and alteration of striatal dopamine uptake, are discussed. It is unclear why lamotrigine induces obsessions in some patients. Controlled studies are necessary to identify the population at risk for obsessionality in bipolar illness following treatment with lamotrigine and to investigate a possible dose-response relationship between obsessive symptoms and lamotrigine.     

拉莫三嗪治疗双相情感障碍的研究进展

拉莫三嗪作为心境稳定剂治疗双相情感障碍已经应用于临床。在2013年最新的CANMAT指南中新增了拉莫三嗪单药或联合其他药物的治疗方案,提示目前应用拉莫三嗪治疗双相情感障碍已受到广泛关注。本文综述了近几年拉莫三嗪在治疗双相情感障碍各亚型中的临床研究、安全性及应用前景,为双相障碍的治疗提供新观点及新思路。     

Lamotrigine

Lamotrigine is a novel antiepileptic that, although its mechanism is not completely understood, appears to affect voltage-activated sodium channels, resulting in inhibition of the presynaptic release of the excitatory neurotransmitter glutamate. It is well absorbed after oral administration. Its route of elimination is hepatic glucuronidation, which is susceptible to both hepatic microsomal enzyme-inducing and -inhibiting agents. In clinical trials lamotrigine was effective as add-on therapy for refractory partial seizures in adults. Small trials suggest the feasibility of monotherapy, but further controlled trials are warranted to support this practice. Additional data indicate the utility of lamotrigine for generalized seizures. Reported side effects are rash, nausea, vomiting, blurred vision, diplopia, and vision abnormalities. Lamotrigine appears to be an attractive alternative to currently available antiepileptics.     

Lamotrigine in mood disorders

Lamotrigine is an anticonvulsant drug with good efficacy and safety in the treatment of epilepsy. There is now substantial evidence that lamotrigine is also useful in treating resistant depression, rapid cycling bipolar affective disorder, depressive episodes in bipolar affective disorder and in the maintenance phase or prophylaxis of bipolar affective disorder. There are possible roles in managing mood changes in borderline personality disorder, reducing chronic pain and treating schizoaffective disorder. The general range of doses found effective in affective disorders is from 50 to 300 mg daily. Clinical use seems to involve a titration of dose upwards over several weeks until the desired effect is obtained. However, further definitive double-blind, randomised controlled trials against gold standard treatments are required. Lamotrigine has a preferable side-effect profile compared to standard agents for bipolar affective disorder such as lithium or carbamazepine. Further research is certainly warranted and, given its tolerability, could point to lamotrigine as the treatment of choice for some affective disorders.     

Gabapentin and lamotrigine in bipolar disorder.

The utility of gabapentin and lamotrigine for the treatment of bipolar disorder is reviewed. Bipolar disorder is characterized by extreme mood fluctuations, including mania, hypomania, depression, and mixed episodes. Extrapolation of postulated mechanisms of anticonvulsant activity in bipolar disorder has led to the use of the newer anticonvulsants gabapentin and lamotrigine for therapy. Both agents appear promising on the basis of limited (often anecdotal) evidence. They may prove effective in patients with difficult cases of bipolar disorder, such as patients with rapid cycling, mixed episodes, and illness refractory to other treatments. Lamotrigine may offer a much-needed treatment alternative for bipolar depression and could be found effective for acute mania, but the need for slow dosage adjustment and the risk of rash may limit overall clinical utility. Gabapentin may offer significant advantages for acute mania: The dosage can be adjusted rapidly, adverse effects are generally minimal, the therapeutic index is high, there is no required laboratory monitoring, and there is minimal potential for interactions with other psychotropics. Until the results of randomized controlled trials are known, however, these two agents should be reserved for patients with bipolar disorder unresponsive to traditional therapies and for patients who cannot tolerate traditional agents. Preliminary evidence indicates that gabapentin and lamotrigine may be useful for the treatment of bipolar disorder.     

The effects of lamotrigine on the pharmacokinetics of lithium

AIMS: The treatment of bipolar disorder often includes use of multiple drug therapies. Lithium is one of the most commonly used treatments, but has a narrow therapeutic window. Lamotrigine, an established antiepileptic drug, is emerging as a potentially important new therapy in the treatment of bipolar disorder. The objective of this two-treatment crossover study was to determine whether lamotrigine affects lithium pharmacokinetics. METHODS: Twenty healthy adult men completed the study. Subjects took 2 g lithium gluconate anhydrous every 12 h in the morning and evening for 5 days and in the morning of day 6, with or without 100 mg lamotrigine once daily in the morning for 6 days. Blood and urine samples were collected on day 6 of both treatments to characterize the pharmacokinetics of lithium using noncompartmental methods. RESULTS: The geometric least-square mean ratio for renal clearance of lithium between the combination treatment and lithium alone treatment was 0.93 (95% confidence interval 0.85-1.02). Both treatments were well tolerated. CONCLUSIONS: Lamotrigine does not cause significant change in the pharmacokinetics of lithium.     

Gabapentin and lamotrigine: novel antiepileptic drugs.

The pharmacokinetics, efficacy, and adverse effects of gabapentin and lamotrigine, two new antiepileptic drugs (AEDs), are reviewed. Gabapentin and lamotrigine are promising advances in the treatment of epilepsy, which has not been satisfactorily controlled by available agents in 25-41% of patients. Gabapentin is chemically similar to gamma-aminobutyric acid, but it is able to pass into the central nervous system. It is effective for the treatment of partial-onset seizures that are refractory to other AEDs. It has no known drug-drug interactions and a relatively benign adverse effect profile, but its short half-life necessitates at least thrice-daily dosing. Lamotrigine is structurally unrelated to the other available AEDs. Its role is currently limited to add-on therapy in patients with partial seizures, with or without secondary generalization, that are resistant to current treatment. The efficacy of lamotrigine in patients with primary generalized tonic-clonic seizures, absence seizures, and Lennox-Gastaut syndrome remains to be validated. The adverse effect profile also remains to be determined. A rash may appear in up to 5% of patients, possibly necessitating discontinuation of the drug. Although lamotrigine does not seem to affect the pharmacokinetics of the other AEDs, the other AEDs affect lamotrigine pharmacokinetics. Lamotrigine can be given once or twice daily. Gabapentin and lamotrigine may be useful in treating patients whose epilepsy is not controlled by other available AEDs; however, further research is needed to confirm their roles in epilepsy treatment.     

Effects of lamotrigine on PCP-evoked elevations in monoamine levels in the medial prefrontal cortex of freely moving rats

Lamotrigine is suggested to have potential as an add-on treatment for patients with schizophrenia. Supporting evidence comes from the efficacy of the drug in models of psychotic-like behaviour induced by N-methyl-D-aspartate (NMDA) receptor antagonists, such as phencyclidine (PCP). These drugs enhance levels of the monoamines in the cortex, which may contribute to their psychotomimetic effects. The ability of lamotrigine to prevent these neurochemical changes has not been examined. We studied PCP-evoked overflow of noradrenaline, dopamine and serotonin in the medial prefrontal cortex of awake rats using microdialysis. Rats were administered lamotrigine or vehicle, followed by PCP. Locomotor activity was also recorded before and after drug treatment. Lamotrigine did not have an influence on basal levels of the monoamines, but significantly reduced PCP-evoked overflow of dopamine and serotonin; PCP-evoked overflow of noradrenaline was also reduced by lamotrigine, but not to a significant degree. In contrast, PCP-induced hyperactivity was unaffected by lamotrigine. It is concluded that lamotrigine can modify PCP-evoked monoamine overflow in the cortex, consistent with an ability to prevent the psychotomimetic effects of NMDA receptor antagonists in rodents and humans. The dissociation between monoamine overflow and locomotor activity suggests the involvement of different brain circuits; relevance to the treatment of schizophrenia is also discussed.     

Neuroprotection by lamotrigine in a rat model of neonatal hypoxic-ischaemic encephalopathy

Hypoxic-ischaemic (HI) encephalopathy is a severe complication of perinatal asphyxia and remains a frequent cause of a variety of brain disorders with long-term effects on the patients' life. The associated brain damage is strongly related to the toxic action of excitatory amino acids, especially glutamate and aspartate. Lamotrigine is an anti-epileptic drug that blocks the voltage-gated sodium channels of the presynaptic neuron and inhibits the release of glutamate. In the present study a well-established model of perinatal asphyxia in 7-d-old rats was used to investigate the effect of lamotrigine on HI-induced damage to different hippocampal brain structures, since disruption of this brain area is thought to play a key role in schizophrenia and epilepsy. Therefore, a combination of ischaemia, induced by unilateral occlusion of the left common carotid artery, followed by exposure to a 1-h period of hypoxia, was carried out in neonatal 7-d-old rats. Immediately after the insult, lamotrigine was given i.p. The histological outcome in the hippocampus was conducted and the tissue levels of glutamate, aspartate, GABA, and glutamine in the same area were determined. A remarkable reduction of HI-evoked damaged neurons in most of the investigated hippocampal regions was noted after lamotrigine administration. Furthermore, lamotrigine decreased the asphyxia-induced hippocampal tissue levels of glutamate and aspartate. Immediately after perinatal asphyxia GABA levels were enhanced, while levels of glutamine were decreased. Lamotrigine administration did not affect either GABA or glutamine levels. These results suggest a neuroprotective effect of lamotrigine in this particular animal model of neonatal HI encephalopathy.     

The tolerability of lamotrigine in children.

Lamotrigine is a novel anticonvulsant, which has proven to be effective both as add-on and monotherapy. 13 studies have demonstrated efficacy in 1096 children with a variety of seizure types. Tolerability information in these studies was collected in a standard fashion, where investigators reported all adverse events regardless of the perceived relationship to the test therapies. Generally, lamotrigine treatment in these clinical trials was generally given at higher initial doses and faster dose escalations than are currently recommended. Most adverse events associated with lamotrigine were mild to moderate in severity and did not result in discontinuation of treatment. Results from placebo-controlled, add-on trials showed that 85% of lamotrigine recipients experienced an adverse event compared with 83% of placebo recipients. Lamotrigine was associated with an increased risk of adverse events in the nervous system (dizziness, tremor, ataxia, and diplopia), gastrointestinal tract (nausea), and urinary tract (infection). The incidence of most adverse events was lower among lamotrigine recipients in monotherapy trials than in add-on trials, suggesting that concurrent anticonvulsant treatment or drug interactions can be confounding risk factors above that of lamotrigine treatment alone. Skin rash associated with hospitalisation and the discontinuation of study drug was reported more frequently by lamotrigine recipients than by placebo recipients and more frequently by children than by adults. The simultaneous use of valproic acid (sodium valproate) was associated with an increased incidence of rash. Lamotrigine, an effective broad spectrum anticonvulsant, is well tolerated in children. The qualitative features of adverse events that occur with lamotrigine treatment are similar for children and adults. The incidence of rash may be reduced with proper initial dosing and dose escalation.     

Lamotrigine treatment of aggression in female borderline-patients: a randomized, double-blind, placebo-controlled study

Anger and aggression are typical in borderline patients. The goal of this study was to compare the efficacy of lamotrigine versus placebo in the treatment of aggression in women meeting the criteria for borderline personality disorder (BPD). We conducted a randomized, double-blind, placebo-controlled study of lamotrigine in 24 female subjects meeting Structured Clinical Interview for DSM-IV (SCID) criteria for BPD. The subjects were randomly assigned in a 2: 1 manner ratio to lamotrigine (n = 18) or placebo (n = 9). Treatment duration was 8 weeks. Primary outcome measures were self-reported changes on the anger scales of the Trait Anger Expression Inventory (STAXI). In comparison with the placebo group, and according to the intention-to-treat principle, highly significant (p < 0.01) changes on four STAXI scales (State-Anger, Trait-Anger, Anger-Out, Anger-Control) were observed in those subjects treated with lamotrigine after 8 weeks. The only exception (p < 0.05) was found on the Anger-In scale, where a difference of only 8.5% (p < 0.2) was found. All the patients tolerated lamotrigine relatively well. Lamotrigine appears to be a safe and effective agent in the treatment of anger in women with criteria-defined BPD as defined by SCID criteria. It did not produce any clinically significant effect on body weight.     

Lamotrigine treatment of aggression in female borderline patients, Part II: an 18-month follow-up

Borderline patients often display pathological aggression. We previously tested lamotrigine, an anti-convulsant, in therapy for aggression in women with borderline personality disorder (BPD) (J Psychopharmacol 2005; 19: 287-291), and found significant changes on most scales of the State-Trait Anger Expression Inventory (STAXI) after eight weeks. To assess the longer-term efficacy of lamotrigine in therapy for aggression in women with BPD, this 18-month follow-up observation was carried out, in which patients (treated with lamotrigine: n = 18; former placebo group: n = 9) were tested every six months. According to the intent-to-treat principle, significant changes on all scales of the STAXI were observed in the lamotrigine-treated subjects. All subjects tolerated lamotrigine relatively well. Lamotrigine appears to be an effective and relatively safe agent in the longer-term treatment of aggression in women with BPD.     

Lamotrigine in the treatment of bipolar disorder

Lamotrigine has undergone a remarkable series of systematic studies since 1994 that now establish it as an efficacious, well-tolerated treatment in bipolar disorder. Its efficacy principally addresses both acute and maintenance phase benefits on depressive symptomatology. These benefits have been demonstrated in placebo-controlled studies, rapid cycling patients, bipolar I and II patients and monotherapy as well as in combination therapy, although this has been less well studied. The drug is exceptionally well-tolerated in long-term treatment, although initial dosing requires gradual dosage escalation to avoid the risk of inducing serious rashes with features within the spectrum of Stevens–Johnson syndrome. Administration with valproate requires a slower dosage titration, whereas, as with many drugs, administration with carbamazepine requires a more rapid dosage increase. In contrast to marketed antidepressants, lamotrigine appears not to induce manic or hypo-manic episodes, nor to increase cycling frequency. This combination of properties makes it a first-choice treatment for acute bipolar depression and continuation treatment, especially, but not limited to, prophylaxis against recurrent depression and depressive symptoms. Lamotrigine appears not to have acute antimanic properties. A small number of studies suggest a broader spectrum of efficacy, including in some axis I disorders that are comorbidly associated with bipolar disorder.     

Lamotrigine in the treatment of bipolar disorder

Lamotrigine has undergone a remarkable series of systematic studies since 1994 that now establish it as an efficacious, well-tolerated treatment in bipolar disorder. Its efficacy principally addresses both acute and maintenance phase benefits on depressive symptomatology. These benefits have been demonstrated in placebo-controlled studies, rapid cycling patients, bipolar I and II patients and monotherapy as well as in combination therapy, although this has been less well studied. The drug is exceptionally well-tolerated in long-term treatment, although initial dosing requires gradual dosage escalation to avoid the risk of inducing serious rashes with features within the spectrum of Stevens-Johnson syndrome. Administration with valproate requires a slower dosage titration, whereas, as with many drugs, administration with carbamazepine requires a more rapid dosage increase. In contrast to marketed antidepressants, lamotrigine appears not to induce manic or hypo-manic episodes, nor to increase cycling frequency. This combination of properties makes it a first-choice treatment for acute bipolar depression and continuation treatment, especially, but not limited to, prophylaxis against recurrent depression and depressive symptoms. Lamotrigine appears not to have acute antimanic properties. A small number of studies suggest a broader spectrum of efficacy, including in some axis I disorders that are comorbidly associated with bipolar disorder.     

Population pharmacokinetics of lamotrigine in elderly patients

Lamotrigine is being used more frequently in elderly patients. Dosing of lamotrigine in elderly patients is based largely on studies from younger adults and not evidence-based data from elderly patients. The goal of this study is to determine the pharmacokinetic parameters, such as clearance, and the factors that have a significant effect on these parameters to provide evidence-based information that can be used to dose elderly patients taking lamotrigine. Lamotrigine plasma concentrations from 148 elderly patients (aged 59-92 years) were used to develop a population pharmacokinetic model. Data were analyzed using NONMEM. Model evaluation was performed using the bootstrap approach and predictive check. The results showed that the blood urea nitrogen/serum creatinine ratio, weight, and phenytoin use significantly affect apparent clearance of lamotrigine. These results show that clinicians may need to take into account these covariates when dosing lamotrigine in this population.