SUDEP and epilepsy-related mortality in pregnancy

Although data are limited, research in 2004 estimated a 10-fold increase in mortality in pregnancy in the United Kingdom in women with epilepsy (WWE) compared to women without epilepsy. We highlight epilepsy mortality in pregnancy based on the 2011 report of the United Kingdom Confidential Enquiries into Maternal Deaths, relating its findings to previous reports and epilepsy-rates in pregnancy. Among 2,291,493 maternities (2006-2008), we estimated 0.6% or 13,978 were in WWE. Fourteen deaths were epilepsy-related, of which 11 (79%) were sudden and unexpected (SUDEP). Nine occurred during pregnancy and five were postpartum. Nine (64%) were in women taking lamotrigine, seven as monotherapy. We estimated that 1:1,000 women died from epilepsy (mostly SUDEP) during or shortly after pregnancy. Epilepsy-related mortality is a significant risk in pregnancy. Antiepileptic drug-related factors may be relevant. The high proportion of women taking lamotrigine may reflect United Kingdom prescribing practice. Recent observations from the European and International Registry of Antiepileptic Drugs and Pregnancy (EURAP), whereby women on lamotrigine, the levels of which significantly decrease in pregnancy, had more difficulties with epilepsy control, argue against this being the sole explanation. Given the potential risks, every attempt should be made to prevent seizures, particularly convulsive, during pregnancy and postpartum. This, we believe, includes being proactive in maintaining lamotrigine levels during pregnancy.

The Clinical Effectiveness and Cost-Effectiveness of Lamotrigine in Borderline Personality Disorder: A Randomized Placebo-Controlled Trial

OBJECTIVE

The authors examined whether lamotrigine is a clinically effective and cost-effective treatment for people with borderline personality disorder.

METHOD

This was a multicenter, double-blind, placebo-controlled randomized trial. Between July 2013 and November 2016, the authors recruited 276 people age 18 or over who met diagnostic criteria for borderline personality disorder. Individuals with coexisting bipolar affective disorder or psychosis, those already taking a mood stabilizer, and women at risk of pregnancy were excluded. A web-based randomization service was used to allocate participants randomly in a 1:1 ratio to receive either an inert placebo or up to 400 mg/day of lamotrigine. The primary outcome measure was score on the Zanarini Rating Scale for Borderline Personality Disorder (ZAN-BPD) at 52 weeks. Secondary outcome measures included depressive symptoms, deliberate self-harm, social functioning, health-related quality of life, resource use and costs, side effects of treatment, and adverse events.

RESULTS

A total of 195 (70.6%) participants were followed up at 52 weeks, at which point 49 (36%) of those in the lamotrigine group and 58 (42%) of those in the placebo group were taking study medication. The mean ZAN-BPD score was 11.3 (SD=6.6) among those in the lamotrigine group and 11.5 (SD=7.7) among those in the placebo group (adjusted difference in means=0.1, 95% CI=-1.8, 2.0). There was no evidence of any differences in secondary outcomes. Costs of direct care were similar in the two groups.

CONCLUSIONS

The results suggest that treating people with borderline personality disorder with lamotrigine is not a clinically effective or cost-effective use of resources.

Nose-to-brain delivery of lamotrigine-loaded PLGA nanoparticles

Direct nose-to-brain delivery of drugs and faster onset of action have made intra-nasal route a much sought-after alternative to conventional routes of drug delivery to the brain. Lamotrigine is used for the treatment and management of neuropathic pain, and in the present work, lamotrigine (LTG)-PLGA nanoparticles were developed for intra-nasal delivery. The LTG-PLGA nanoparticles were prepared using modified nanoprecipitation method via high-speed homogenization and ultra-sonication techniques. Entrapment efficiency (EE%) of developed LTG-PLGA-NPs was found to be 84.87 ± 1.2% with drug loading of 10.21 ± 0.89%. The particle size of developed nanoparticles was found to be 184.6 nm with PDI value of 0.082 and zeta potential of - 18.8 mV. Dissolution profiles were studied in PBS (pH 7.4), simulated nasal fluid, and simulated cerebrospinal fluid where almost complete release was observed within 5 h in CSF. In vitro, cytotoxicity was analyzed using MTT assay where dose-dependent cytotoxicity was observed for developed LTG-PLGA-NPs. In vitro cytokine analysis showed positive effects of LTG-PLGA-NPs as pro-inflammatory cytokine suppressors. Further, in vivo studies were performed for radiolabeled formulation and drug (^99mTc-LTG-PLGA-NPs and ^99mTc-LTG-aqueous) using Sprague Dawley rats where with the help of gamma scintigraphy studies, various routes of administration viz. oral, intra-nasal, and intra-venous were compared. Various pharmacokinetic parameters were evaluated using biodistribution studies to estimate the drug levels in blood and brain. For ^99mTc-LTG-PLGA-NPs via intra-nasal route, drug targeting efficiency (DTE%) was found to be 129.81% and drug target organ transport (DTP%) to be 22.81% in brain with C_max of 3.82%/g within T_max 1.5 h. Thus, the developed PLGA nanoparticles for intra-nasal delivery provide a possible alternative for existing available drug formulation for neuropathic pain management.

Generic lamotrigine versus brand-name Lamictal bioequivalence in patients with epilepsy: A field test of the FDA bioequivalence standard

OBJECTIVE

To test the current U.S. Food and Drug Administration (FDA) bioequivalence standard in a comparison of generic and brand-name drug pharmacokinetic (PK) performance in "generic-brittle" patients with epilepsy under clinical use conditions.

METHODS

This randomized, double-blind, multiple-dose, steady-state, fully replicated bioequivalence study compared generic lamotrigine to brand-name Lamictal in "generic-brittle" patients with epilepsy (n = 34) who were already taking lamotrigine. Patients were repeatedly switched between masked Lamictal and generic lamotrigine. Intensive PK blood sampling at the end of each 2-week treatment period yielded two 12-h PK profiles for brand-name and generic forms for each patient. Steady-state area under the curve (AUC), peak plasma concentration (Cmax ), and minimum plasma concentration (Cmin ) data were subjected to conventional average bioequivalence (ABE) analysis, reference-scaled ABE analysis, and within-subject variability (WSV) comparisons. In addition, generic-versus-brand comparisons in individual patients were performed. Secondary clinical outcomes included seizure frequency and adverse events.

RESULTS

Generic demonstrated bioequivalence to brand. The 90% confidence intervals of the mean for steady-state AUC, Cmax , and Cmin for generic-versus-brand were 97.2-101.6%, 98.8-104.5%, and 93.4-101.0%, respectively. The WSV of generic and brand were also similar. Individual patient PK ratios for generic-versus-brand were similar but not identical, in part because brand-versus-brand profiles were not identical, even though subjects were rechallenged with the same product. Few subjects had seizure exacerbations or tolerability issues with product switching. One subject, however, reported 267 focal motor seizures, primarily on generic, although his brand and generic PK profiles were practically identical.

SIGNIFICANCE

Some neurologists question whether bioequivalence in healthy volunteers ensures therapeutic equivalence of brand and generic antiepileptic drugs in patients with epilepsy, who may be at increased risk for problems with brand-to-generic switching. Bioequivalence results in "generic-brittle" patients with epilepsy under clinical conditions support the soundness of the FDA bioequivalence standards. Adverse events on generic were not related to the small, allowable PK differences between generic and brand.

Changes in mood stabilizer prescription patterns in bipolar disorder

BACKGROUND

Lithium is a first line treatment option in bipolar disorder, but several alternative treatments have been introduced in recent years, such as antiepileptic and atypical antipsychotic drugs. Little is known about how this has changed the prescription patterns. We investigated possible changes in the use of mood stabilizers and antidepressants in Sweden during 2007-2013.

METHODS

Data was collected from Swedish registers: the National Quality Assurance Register for bipolar disorder (BipoläR), the Prescribed Drug Register, and the Patient Register. Logistic regression models with drug use as outcomes were used to adjust for confounding factors such as sex, age, year of registration, and subtypes of bipolar disorder.

RESULTS

In both bipolar subtypes, lithium use decreased steadily during the study period, while the use of lamotrigine and quetiapine increased. The use of valproate decreased in bipolar II disorder and the use of olanzapine decreased among women. The use of antidepressant remained principally unchanged but increased somewhat in bipolar I disorder.

LIMITATIONS

We only report data from 2007 as the coverage of BipoläR prior to 2007 was too low to allow for reliable analyses.

CONCLUSION

Significant changes in the prescription of drugs in the treatment of bipolar disorder have occurred in recent years in Sweden. Further studies are needed to clarify whether these changes alter the outcome in bipolar disorder.

Behavioral outcomes in children exposed prenatally to lamotrigine, valproate, or carbamazepine

OBJECTIVES

To evaluate adaptive behavior outcomes of children prenatally exposed to lamotrigine, valproate, or carbamazepine, and to determine if these outcomes were dose-dependent.

METHODS

Data were collected from women enrolled in the North American Anti epileptic Drug (AED) Pregnancy Registry who had taken lamotrigine, valproate, or carbamazepine monotherapies throughout pregnancy to suppress seizures. The adaptive behavior of 252 exposed children (including 104 lamotrigine-exposed, 97 carbamazepine-exposed, and 51 valproate-exposed), ages 3- to 6-years-old, was measured using the Vineland-II Adaptive Behavior Scales, administered to each mother by telephone. Mean Adaptive Behavior Composite (ABC), domain standard scores for communication, daily living, socialization and motor skills, and adaptive levels were analyzed and correlated with first trimester drug dose.

RESULTS

After adjusting for maternal age, education, folate use, cigarette and alcohol exposure, gestational age, and birth weight by propensity score analysis, the mean ABC score for valproate-exposed children was 95.6 (95% CI [91, 101]), versus 100.8 (95% CI [98, 103]) and 103.5 (95% CI [101, 106]) for carbamazepine- and lamotrigine-exposed children, respectively (ANOVA; p=0.017). Significant differences were observed among the three drug groups in the ABC (p=0.017), socialization (p=0.026), and motor (p=0.018) domains, with a trend toward significance in the communication domain (p=0.053). Valproate-exposed children scored lowest and lamotrigine-exposed children scored highest in every category. Valproate-exposed children were most likely to perform at a low or moderately low adaptive level in each category. Higher valproate dose was associated with significantly lower ABC (p=0.020), socialization (p=0.009), and motor (p=0.041) scores before adjusting for confounders. After adjusting for the above variables, increasing VPA dose was associated with decreasing Vineland scores in all domains, but the relationships were not statistically significant. No dose effect was observed for carbamazepine or lamotrigine.

CONCLUSIONS

Unlike carbamazepine and lamotrigine, prenatal valproate exposure was associated with adaptive behavior impairments with specific deficits in socialization and motor function, along with a relative weakness in communication. Increasing valproate dose was associated with a decline in adaptive functioning. This finding of a linear dose-dependent teratogenic effect suggests that valproate should be avoided at any dose during pregnancy. However, some women with epilepsy controlled only by valproate will decide, in consultation with their provider, that the benefits of continuing valproate during pregnancy outweigh the fetal risks. Faced with difficult choices, clinicians should be supportive as these patients consider their options.

Lamotrigine encapsulated intra-nasal nanoliposome formulation for epilepsy treatment: Formulation design, characterization and nasal toxicity study

The purpose of this study was to develop lamotrigine nanoliposomes (LTG-NLs) for the treatment in seizures. The formulation was prepared using thin film hydration and rehydration method using the phospholipon 90 G, cholesterol and tween 80 as main ingredients. The nanoliposomes were optimized by plucket burman design (PBD) and response surface methodology (RSM) optimization techniques. The optimized LTGNLopt was further characterized for surface morphology, in-vitro release, stability study, confocal laser scanning microscopic (CLSM) study and naso toxicity study. The results showed that LTGNLopt shown nano size with high entrapment and drug release. The ex-vivo permeation study and confocal laser microscopy study confirmed the enhancement in permeation across the goat nasal mucosa. From the study, it was concluded that the independent variables used to optimize the NLs shown significant effect on the dependent variables and consider effective lipid carrier system for intranasal delivery.

Direct nose-to-brain delivery of lamotrigine following intranasal administration to mice

Pharmacoresistance is considered one of the major causes underlying the failure of the anticonvulsant therapy, demanding the development of alternative and more effective therapeutic approaches. Due to the particular anatomical features of the nasal cavity, intranasal administration has been explored as a means of preferential drug delivery to the brain. The purpose of the present study was to assess the pharmacokinetics of lamotrigine administered by the intranasal route to mice, and to investigate whether a direct transport of the drug from nose to brain could be involved. The high bioavailability achieved for intranasally administered lamotrigine (116.5%) underscored the fact that a substantial fraction of the drug has been absorbed to the systemic circulation. Nonetheless, the heterogeneous biodistribution of lamotrigine in different brain regions, with higher concentration levels attained in the olfactory bulb comparatively to the frontal cortex and the remaining portion of the brain, strongly suggest that lamotrigine was directly transferred to the brain via the olfactory neuronal pathway, circumventing the blood-brain barrier. Therefore, it seems that intranasal route can be assumed as a suitable and valuable drug delivery strategy for the chronic treatment of epilepsy, also providing a promising alternative approach for a prospective management of pharmacoresistance.

The HLA-A*2402/Cw*0102 haplotype is associated with lamotrigine-induced maculopapular eruption in the Korean population

The use of lamotrigine (LTG) can be limited by the occurrence of cutaneous adverse drug reactions (cADRs) that range from maculopapular eruption (MPE) to the more severe Stevens-Johnson syndrome and toxic epidermal necrolysis. A few human leukocyte antigen (HLA)-related genetic risk factors for carbamazepine-induced cADR have been identified. However, the HLA-related genetic risk factors associated with LTG-induced cADR are not yet well known. We performed HLA genotyping in 50 Korean patients with epilepsy, including 21 patients presenting LTG-induced MPE and 29 LTG-tolerant patients. A significant association between the HLA-A*2402 allele and LTG-induced MPE was identified, in comparison with the LTG-tolerant group (odds ratio [OR] 4.09, p = 0.025) and the general Korean population (OR 3.949, p = 0.005). The frequencies of the Cw*0102 or Cw*0702 alleles were significantly higher in the LTG-MPE group than in the Korean population, whereas the frequency of the A*3303 allele was lower. The coexistence of the A*2402 and Cw*0102 alleles was significantly associated with the LTG-MPE group when compared to the LTG-tolerant group (OR 7.88, p = 0.007). In addition, the Cw*0701 allele was more frequent in the LTG-tolerant group than in the Korean population. These findings suggest the presence of HLA-related genetic risk factors for LTG-induced MPE in the Korean population.

Predictive markers for carbamazepine and lamotrigine-induced maculopapular exanthema in Han Chinese

The aims of this study were to clarify the possible associations of carbamazepine (CBZ)- and lamotrigine (LTG)-induced maculopapular exanthema (MPE) with the human leukocyte antigen (HLA) alleles in Chinese patients. A total of 249 subjects, including 40 patients with CBZ-induced MPE (CBZ-MPE), 43 patients with LTG-induced MPE (LTG-MPE), 52 CBZ-tolerant controls, 42 LTG-tolerant controls and 72 healthy controls, were included in this study. High-resolution HLA genotyping was performed by a specific kit. Differences in the allele frequencies among the groups were assessed. The allele frequencies of HLA-A*0201 and HLA-DRB1*1405 were significantly higher (P=0.033 and P=0.003, respectively), but those of HLA-B*5801 and HLA-DRB1*0301 (P=0.037 and P=0.024, respectively) were lower in the CBZ-MPE patients when compared with the CBZ-tolerant group. We also observed two significantly increased alleles of HLA-A*3001 and HLA-B*1302 (P=0.013 and P=0.013, respectively) and a decreased allele of HLA-A*3303 (P=0.048) in the LTG-MPE patients when compared with those in the LTG-tolerant group. Our results support the hypothesis that these HLA alleles contribute to the genetic susceptibility to CBZ/LTG-MPE and may be valuable as potential biomarkers for CBZ/LTG-MPE in Han Chinese.

Influence of valproic acid concentration and polymorphism of UGT1A4*3, UGT2B7 -161C > T and UGT2B7*2 on serum concentration of lamotrigine in Chinese epileptic children

PURPOSE

To investigate the impact of valproic acid (VPA) and genetic polymorphism of the major metabolizing enzyme (UGT1A4, UGT2B7) of lamotrigine (LTG) and VPA on LTG concentration in Chinese epileptic children.

METHODS

Three single nucleotide polymorphisms (UGT1A4*3, UGT2B7 -161C > T and UGT2B7*2) were analyzed by polymerase chain reaction-restriction fragment length polymorphism or direct DNA sequencing. The concentrations of LTG and VPA were measured by high-performance liquid chromatography (HPLC) and fluorescence polarization immunoassay, respectively. The adjusted concentration of LTG was defined as the concentration-to-dose-ratio (CDRLTG). Data analysis was performed using IBM SPSS Statistics 21.0.

RESULTS

A total of 56 patients treated with LTG as monotherapy and 158 patients treated with LTG plus VPA were included in this study. In the polytherapy group, LTG concentration showed a good linear relationship with gender, age, daily LTG dose, VPA concentration, and UGT1A4*3 polymorphism, but had no relationship with the polymorphism of UGT2B7 -161C > T or UGT2B7*2. Moreover, LTG concentration and CDRLTG for the UGT1A4*3 were higher compared to UGT1A4*1 (LTG: 7.24 ± 3.51 vs 5.26 ± 3.27 μg/mL, p = 0.001; CDRLTG: 2.75 ± 1.02 vs 2.14 ± 0.96 μg/mL per mg/kg, p < 0.001, respectively). In the monotherapy group, there was no statistical difference between UGT1A4*3 and UGT1A4*1 in LTG concentration or CDRLTG. The patients in the polytherapy group were divided into two subgroups according to VPA concentration (lower/higher: 10-50/50-125 μg/mL). CDRLTG values of the patients carrying the UGT1A4*3 genotype were higher compared to UGT1A4*1*1 (2.86 ± 1.03 vs 2.22 ± 0.94 μg/mL per mg/kg, p = 0.001) only when the VPA concentration was higher.

CONCLUSIONS

UGT1A4*3 polymorphism had an effect on LTG concentration only with VPA co-administration, and the effect was remarkable when VPA concentration was higher.

Frequencies of UGT1A4*2 (P24T) and *3 (L48V) and their effects on serum concentrations of lamotrigine

The gene encoding uridine diphosphate glucuronosyltransferase (UGT) 1A4 shows considerable polymorphism. Several common drugs are metabolised by UGT1A4, among them lamotrigine (LTG). Experimental and clinical studies suggest that certain variants of UGT1A4 are associated with altered enzyme activity. However, results are conflicting. This clinical study aimed to investigate the frequencies of two common UGT1A4 variants, *2 (P24T) and *3 (L48V), and their potential effects on serum concentrations of LTG. The *2 variant was associated with a trend towards higher serum concentrations, while the *3 variant was associated with significantly lower serum concentrations of LTG. The calculated allele frequencies were in the same range as in earlier studies on Caucasian populations. To our knowledge, this is the first study suggesting a clinical effect of UGT1A4*2. Further study is needed to confirm this finding.

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.

Weight changes associated with antiepileptic mood stabilizers in the treatment of bipolar disorder

OBJECTIVE

To present up-to-date information and recommendations on the management of body weight changes during the use of antiepileptic mood stabilizers in bipolar disorder to help clinicians and patients make well-informed, practical decisions.

DATA SOURCES

Umbrella review. Systematic reviews and meta-analyses on the prevention, treatment, and monitoring of body weight changes as a side effect of the mood stabilizers valproate, lamotrigine, topiramate, and carbamazepine were identified in Embase (2010-2015, no language restrictions).

STUDY SELECTION

The search yielded 18 relevant publications on antiepileptic mood stabilizers and weight changes in bipolar disorder.

DATA EXTRACTION

Relevant scientific evidence was abstracted and put into a clinical perspective by a multidisciplinary expert panel of clinicians with expertise in the treatment of bipolar disorders across all age groups and a patient representative.

RESULTS

Valproate has been proven to be associated with weight gain in up to 50% of its users, and can be detected 2-3 months after initiation. Carbamazepine has been proven to have a low risk of weight gain. Lamotrigine and topiramate are associated with weight loss. Other option for this sentence = Weigth gain has been proven to be associated with valproate use in up to 50% of its users, and can be detected within 2-3 months after initiation.

CONCLUSION

Each antiepileptic mood stabilizer has specific effects on body weight and accordingly requires a discrete education, prevention, monitoring, and treatment strategy. Clinicians are recommended to adopt an active, anticipatory approach, educating patients about weight change as an important side effect in order to come to informed shared decisions about the most suitable mood stabilizer.

Association between HLA alleles and lamotrigine-induced cutaneous adverse drug reactions in Asian populations: A meta-analysis

PURPOSE

The aim of this study was to assess the association between human leukocyte antigen (HLA) variants and lamotrigine (LTG)-induced cutaneous adverse drug reactions (cARDs).

METHODS

A comprehensive literature search was conducted on the relationship of HLA alleles with LTG-induced cADRs in Asian populations, through PubMed, Embase, and Cochrane Library. The last search was in February 2018. The pooled odds ratio (OR) with 95% confidence interval (95% CI) was used to access the strength of the association between an HLA allele and LTG-induced cADRs.

RESULTS

A total of 11 studies met the inclusion criteria and were enrolled in our meta- analysis, which were based on Chinese, Korean, and Thai populations. Among these populations, we observed that HLA-B*1502 is a risk allele for LTG-induced Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) in Chinese populations (pooled OR 2.4, 95% CI: 1.20-4.78, P = 0.01), HLA-A*2402 was found to be a significant risk allele for both SJS/TEN (pooled OR 3.50, 95% CI: 1.61-7.59, P = 0.002) and maculopapular eruption (MPE) (pooled OR 2.14, 95% CI: 1.10-4.16, P = 0.03), and HLA-B*3303 was considered to be a protective marker for MPE in Chinese and Korean populations (pooled OR 0.2, 95% CI 0.06-0.64, P = 0.007).

CONCLUSIONS

In Asian populations, HLA-B*1502 is a risk factor for LTG-induced bullous lesions such as SJS/TEN in Chinese populations, and HLA-A*2402 is associated with the susceptibility to either SJS/TEN or MPE. HLA-A*3303 is a protective allele against LTG-induced MPE in Chinese and Korean populations.

Balancing benefits and harms of treatments for acute bipolar depression

BACKGROUND

Bipolar depression is more pervasive than mania, but has fewer evidence-based treatments.

METHODS

Using data from multicenter, randomized, double-blind, placebo-controlled trials and meta-analyses, we assessed the number needed to treat (NNT) for response and the number needed to harm (NNH) for selected side effects for older and newer acute bipolar depression treatments.

RESULTS

The 2 older FDA-approved treatments for bipolar depression, olanzapine-fluoxetine combination (OFC) and quetiapine (QTP) monotherapy, were efficacious (response NNT=4 for OFC, NNT=6 for QTP), but similarly likely to yield harms (OFC weight gain NNH=6; QTP sedation/somnolence NNH=5). Commonly used unapproved agents (lamotrigine monotherapy and adjunctive antidepressants) tended to be well-tolerated (with double-digit NNHs), although this advantage was at the cost of inadequate efficacy (response NNT=12 for lamotrigine, NNT=29 for antidepressants). In contrast, the newly approved agent lurasidone was not only efficacious (response NNT=5 for monotherapy, NNT=7 as adjunctive therapy), but also had enhanced tolerability (NNH=15 for akathisia [monotherapy], NNH=16 for nausea [adjunctive]). Although adjunctive armodafinil appeared well tolerated, its efficacy in bipolar depression has not been consistently demonstrated in randomized controlled trials.

LIMITATIONS

NNT and NNH are categorical metrics; only selected NNHs were assessed; limited generalizability of efficacy (versus effectiveness) studies.

CONCLUSION

For acute bipolar depression, older approved treatments may have utility in high-urgency situations, whereas lamotrigine and antidepressants may have utility in low-urgency situations. Newly approved lurasidone may ultimately prove useful in diverse situations. New drug development needs to focus on not only efficacy but also on tolerability.

Rapid loss of efficacy to the antiseizure drugs lamotrigine and carbamazepine: a novel experimental model of pharmacoresistant epilepsy

PURPOSE

Kindling is a well-established model of secondarily generalized partial seizures that is widely employed in the search for novel antiseizure drugs. During the kindling and postkindling acquisition phase, an active process of neuronal remodeling occurs. We tested the hypothesis that exposure to the voltage-gated sodium channel blockers lamotrigine (LTG) and carbamazepine (CBZ) during the period of active remodeling will lead to a diminished therapeutic effect.

METHODS

Two days after the last kindling stimulation, fully kindled rats were randomized to receive either 0.5% methyl cellulose (MC), LTG (30 mg/kg), or CBZ (40 mg/kg). The effect of LTG and CBZ on behavioral seizure severity and electrographic afterdischarge duration (ADD) was recorded. One week after this treatment, rats in both groups were rechallenged with LTG 30 or CBZ 40 mg/kg and their seizure score and ADD recorded. In vitro efficacy of LTG on neuronal action potentials was also evaluated using whole cell current clamp recording in hippocampal brain slices obtained from kindled control rats, LTG-sensitive kindled rats, and LTG-resistant kindled rats.

KEY FINDINGS

When acutely administered 48 h after the last kindling stimulation, LTG and CBZ blocked the expression of behavioral seizures and reduced the ADD. In contrast, a second challenge dose of LTG or CBZ administered after a 7-day "no drug, no stimulation" period did not result in reduction of either the seizure score or the ADD. Interestingly, the potassium channel opener, ezogabine, also known as retigabine (EZG; 40 mg/kg), blocked the expression of behavioral seizures at both time points evaluated (i.e., 2 days and 9 days after last stimulation). In vivo resistance to LTG was associated with a similar reduction in the ability of LTG to limit action potential firing in CA1 neurons. LTG (50 μm) significantly decreased the number of action potentials generated by a depolarizing current pulse in neurons recorded from slices obtained from kindled control and LTG-sensitive rats, but not in slices obtained from LTG-resistant rats.

SIGNIFICANCE

Collectively, results obtained from both in vivo and in vitro studies demonstrate that even a single exposure to the sodium channel blockers LTG, or CBZ, during the postkindling remodeling phase leads to an altered pharmacologic response to these two ASDs, but not to EZG. The LTG- and CBZ-resistant amygdala kindled rats may serve as a useful model of therapy-resistant epilepsy.

Polymorphisms of ABCG2, ABCB1 and HNF4α are associated with Lamotrigine trough concentrations in epilepsy patients

Lamotrigine (LTG) is commonly used to control seizure in epilepsy patients and with referenced therapeutic windows in clinical practice. This study is to identify and characterize the function of genetic variants that influence the trough concentrations of LTG in epilepsy patients following monotherapy regimen (37.5-250 mg/d). Twelve single nucleotide polymorphisms (SNPs) involved in LTG metabolism and transport pathways, including UGT2B7, ABCB1, ABCG2, NR1I2 and HNF4α were genotyped in 140 Chinese epilepsy patients. Steady-state trough concentration of LTG was measured by a high-performance liquid chromatography method. Polymorphisms in ABCG2 rs2231142, rs3114020, HNF4α rs2071197 and ABCB1 rs1128503 were found to be associated with LTG CDR (concentration/dose normalized by body weight). In addition, multiple linear regression analysis revealed that ABCG2 rs2231142 had a remarkable effect on LTG concentrations which is stated to be 4.8% of the variability of LTG and may also help to interpret ethnic difference in LTG pharmacokinetics. Our findings provided new insights that SNPs of genes involved in the transport of LTG contribute to interpatient variation in LTG pharmacokinetics. Future studies are necessary to determine whether these SNPs can be used to provide LTG dosing guidance and influence seizure control and adverse reaction of LTG.

Trends in pharmacotherapy in patients referred to a bipolar specialty clinic, 2000-2011

OBJECTIVE

To assess mood stabilizer (MS) and second-generation antipsychotic (SGA) prescribing trends in bipolar disorder (BD) outpatients referred to a bipolar disorder specialty clinic over the past 12 years.

METHOD

BD outpatients referred to the Stanford University Bipolar Disorder Clinic during 2000-2011 were assessed with the Systematic Treatment Enhancement Program for BD (STEP-BD) Affective Disorders Evaluation. Prescription rates for MSs and SGAs were compared during the first (2000-2005) and second (2006-2011) six years.

RESULTS

Among 597 BD patients (mean±SD age 35.4±8.6 years; 58.1% female; 40.7% Type I, 43.6% Type II, and 15.7% Type Not Otherwise Specified; taking 2.6±1.7 prescription psychotropic medications), lamotrigine, quetiapine, and aripiprazole usage more than doubled, from 14.7% to 37.2% (p<0.0001), 7.2% to 19.7% (p<0.0001), and 3.1% to 10.9% (p=0.0003), respectively, while olanzapine and risperidone use decreased by more than half from 15.0% to 6.6% (p=0.0043), and from 8.7% to 3.8% (p=0.039), respectively. SGA use increased from 34.1% to 44.8% (p=0.013), although MS use continued to be more common (in 65.2% for 2006-2011). Use of other individual MSs and SGAs and MSs as a class did not change significantly.

CONCLUSIONS

Over 12 years, in patients referred to a BD specialty clinic, lamotrigine, quetiapine, and aripiprazole use more than doubled, and olanzapine and risperidone use decreased by more than half. Tolerability (for lamotrigine, aripiprazole, olanzapine, and risperidone) more than efficacy (for quetiapine) differences may have driven these findings. Additional studies are needed to explore the relative influences of enhanced tolerability versus efficacy upon prescribing practices in BD patients.

Expression and functional relevance of UGT1A4 in a cohort of human drug-resistant epileptic brains

PURPOSE

Brain drug bioavailability is regulated by the blood-brain barrier (BBB). It was recently suggested that cytochrome P450 (CYP) enzymes could act in concert with multidrug transporter proteins to regulate drug penetration and distribution into the diseased brain. The possibility that phase II metabolic enzymes could be expressed in the epileptic brain has been not evaluated. Phase II enzymes are involved in the metabolism of common antiepileptic drugs (AEDs).

METHODS

Phase II enzyme UGT1A4 brain expression was evaluated in temporal lobe resections from patients with epilepsy. UGT1A4 expression was determined by western blot and immunocytochemistry in primary cultures of human drug-resistant brain endothelial human brain epileptic endothelial cells (EPI-EC)s and commercially available control cells human brain microvascular endothelial cells (HBMECs). Lack of DNA condensation measured by 4',6-diamidino-2-phenylindole (DAPI) was used as a surrogate marker of cell viability and was correlated to UGT1A4 expression high performance liquid chromatography ultraviolet detection (HPLC-UV) was used to quantify lamotrigine metabolism by EPI-EC and HBMEC. The appearance of the specific lamotrigine metabolite, 2-n glucuronide (MET-1), was also evaluated. Lamotrigine and MET-1 levels were measured in selected surgical brain and matched blood samples.

KEY FINDINGS

UGT1A4 expression was observed in BBB endothelial cells and neurons. Our quantification study revealed variable levels of UGT1A4 expression across the brain specimens analyzed. Neurons devoid of UGT1A4 expression displayed nuclear DAPI condensation, a sign of cellular distress. UGT1A4 overexpression in EPI-EC, as compared to HBMEC, was reflected by a proportional increase in lamotrigine metabolism. The lamotrigine metabolite, MET-1, was formed in vitro by EPI-EC and, to a lesser extent, by HBMEC. HPLC-UV measurements of brain and blood samples obtained from patients receiving lamotrigine prior to surgery revealed the presence of lamotrigine and its metabolites in the brain.

SIGNIFICANCE

These initial results suggest the presence of a phase II enzyme in the epileptic brain. Further studies are required to fully describe the pattern of brain UGT1A4 expression in relation to clinical variables and drug resistance.

Metabolome-wide association study of anti-epileptic drug treatment during pregnancy

Pregnant women with epilepsy (PWWE) require continuous anti-epileptic drug (AED) treatment to avoid risk to themselves and fetal risks secondary to maternal seizures, resulting in prolonged AED exposure to the developing embryo and fetus. The objectives of this study were to determine whether high-resolution metabolomics is able to link the metabolite profile of PWWE receiving lamotrigine or levetiracetam for seizure control to associated pharmacodynamic (PD) biological responses. Untargeted metabolomic analysis of plasma obtained from 82 PWWE was completed using high-resolution mass spectrometry. Biological alterations due to lamotrigine or levetiracetam monotherapy were determined by a metabolome-wide association study that compared patients taking either drug to those who did not require AED treatment. Metabolic changes associated with AED use were then evaluated by testing for drug-dose associated metabolic variations and pathway enrichment. AED therapy resulted in drug-associated metabolic profiles recognizable within maternal plasma. Both the parent compounds and major metabolites were detected, and each AED was correlated with other metabolic features and pathways. Changes in metabolites and metabolic pathways important to maternal health and linked to fetal neurodevelopment were detected for both drugs, including changes in one‑carbon metabolism, neurotransmitter biosynthesis and steroid metabolism. In addition, decreased levels of 5-methyltetrahydrofolate and tetrahydrofolate were detected in women taking lamotrigine, which is consistent with recent findings showing increased risk of autism spectrum disorder traits in PWWE using AED. These results represent a first step in development of pharmacometabolomic framework with potential to detect adverse AED-related metabolic changes during pregnancy.

Quality by Design approach for studying the impact of formulation and process variables on product quality of oral disintegrating films

The present investigation was carried out to understand the impact of formulation and process variables on the quality of oral disintegrating films (ODF) using Quality by Design (QbD) approach. Lamotrigine (LMT) was used as a model drug. Formulation variable was plasticizer to film former ratio and process variables were drying temperature, air flow rate in the drying chamber, drying time and wet coat thickness of the film. A Definitive Screening Design of Experiments (DoE) was used to identify and classify the critical formulation and process variables impacting critical quality attributes (CQA). A total of 14 laboratory-scale DoE formulations were prepared and evaluated for mechanical properties (%elongation at break, yield stress, Young's modulus, folding endurance) and other CQA (dry thickness, disintegration time, dissolution rate, moisture content, moisture uptake, drug assay and drug content uniformity). The main factors affecting mechanical properties were plasticizer to film former ratio and drying temperature. Dissolution rate was found to be sensitive to air flow rate during drying and plasticizer to film former ratio. Data were analyzed for elucidating interactions between different variables, rank ordering the critical materials attributes (CMA) and critical process parameters (CPP), and for providing a predictive model for the process. Results suggested that plasticizer to film former ratio and process controls on drying are critical to manufacture LMT ODF with the desired CQA.

Effects of UGT1A4 genetic polymorphisms on serum lamotrigine concentrations in Chinese children with epilepsy

Lamotrigine (LTG) is widely used in the treatment of children with epilepsy. Genetic polymorphisms in genes encoding drug-metabolizing enzymes may be an important source of interindividual variability in LTG metabolism. The aim of this study was to evaluate the effects of genetic polymorphisms of uridine diphosphate glucuronosyltransferase (UGT) 1A4 (UGT1A4) gene on LTG serum concentrations in children with epilepsy. The UGT1A4 142T > G in the coding regions and -219C > T/-163G > A in the 5'-upstream regions were genotyped using polymerase chain reaction amplification followed by direct automated DNA sequencing in 148 patients treated with polytherapy with LTG and valproic acid (VPA). Our data showed that patients carrying the variant UGT1A4 -219C > T/-163G > A genotypes or alleles had significantly higher adjusted LTG concentrations than those carrying the wild-type genotypes or alleles. However, the significant association was abrogated after adjusted by age, body weight, and adjusted VPA concentration. No associations were detected between the UGT1A4 142T > G genotypes or alleles and adjusted LTG concentrations. Taken together, these results suggest that the -219C > T/-163G > A mutations in the 5'-upstream regions of the UGT1A4 gene affect LTG pharmacokinetics, with which is potentially interfered by age, body weight, and concomitant VPA administration.

Risk of a lamotrigine-related skin rash: current meta-analysis and postmarketing cohort analysis

PURPOSE

We systematically reviewed studies to provide current evidence on the incidence and risk of skin rash in patients with LTG therapy.

METHODS

PubMed and Scopus databases, up to 15 March 2014 were searched to identify relevant studies. Eligible studies included prospective studies, retrospective studies and postmarketing reports, which included data of skin rash in patients with LTG therapy.

RESULTS

Forty-one articles met the entry criteria. A total of 4447 patients with LTG therapy from 26 prospective studies, 2977 patients from 8 retrospective studies, and 26,126 patients from 5/7 postmarketing reports were included. The overall incidence of skin rash with LTG therapy was 9.98% (444/4447) from prospective studies, 7.19% (214/2977) from retrospective studies, and 2.09% (547/26,126) from postmarketing reports. A meta-analysis of the risk of skin rash in 21 prospective studies, did not show a significant difference between patients with LTG and other drugs, including placebo, other ADEs or lithium (OR 0.99-2.41). In 6 respective studies, there was a significantly higher OR in patients with LTG compared with those with non-aromatic AEDs. However, there was no significant difference in rash risk between patients with LTG and aromatic AEDs.

CONCLUSIONS

Our study showed that LTG significantly increased the risk of developing a skin rash compared to non-aromatic AEDs. Our results support the need for large prospective population-based studies and clinical trials to determine whether LTG increases the risk of developing a skin rash than compared to other drugs.