Comparative analysis of adverse drug reactions associated with new antiseizure medications from the Korea Adverse Event Reporting System database.

OBJECTIVE: This study aimed to compare and characterize the safety profiles of new antiseizure medications (ASMs) using a nationwide pharmacovigilance database from a long-term perspective in Korea. METHODS: We reviewed adverse event reports from the Korea Adverse Event Reporting System database between January 2013 and December 2022 for descriptive analysis of six new ASMs (lacosamide, levetiracetam, lamotrigine, oxcarbazepine, topiramate, and zonisamide). We investigated the frequency and characteristics of adverse drug reactions (ADRs) based on the MedDRA terminology, system organ classes, and modified WHO classification. RESULTS: We identified 5,733 reported cases of ADRs. The commonly reported ADRs associated with total ASMs were rash/urticaria (1,822, 31.8 %), dizziness (409, 7.1 %), somnolence/drowsiness (311, 5.4 %), and hepatotoxic effects (273, 4.8 %). Type B (idiosyncratic) effects (2,932; 51.1 %) were more commonly reported than Type A (related to known drug mechanisms) effects (2,613; 45.6 %). Skin and subcutaneous tissue disorders and type B effects were most commonly reported for lamotrigine and oxcarbazepine, whereas nervous system disorders and type A effects were most commonly reported for lacosamide, topiramate, and zonisamide. The pediatric group (<18 years) exhibited skin and subcutaneous tissue disorders and type B effects relatively more frequently than the adult and older adult groups. CONCLUSION: Hypersensitivity skin reactions and type B effects remained significant ADRs in the new ASMs; however, type A effects were more commonly reported in some ASMs. The pediatric group showed a higher rate of type B effects. Overall, new ASMs should also be used with caution.

Risk of Major Congenital Malformations and Exposure to Antiseizure Medication Monotherapy.

Importance: Women with epilepsy (WWE) require treatment with antiseizure medications (ASMs) during pregnancy, which may be associated with an increased risk of major congenital malformations (MCMs) in their offspring. Objective: To investigate the prevalence of MCMs after prenatal exposure to 8 commonly used ASM monotherapies and changes in MCM prevalence over time. Design, Setting, and Participants: This was a prospective, observational, longitudinal cohort study conducted from June 1999 to October 2022. Since 1999, physicians from more than 40 countries enrolled ASM-treated WWE before pregnancy outcome was known and followed up their offspring until 1 year after birth. Participants aged 14 to 55 years who were exposed to 8 of the most frequently used ASMs during pregnancy were included in this study. Data were analyzed from April to September 2023. Exposure: Maternal use of ASMs at conception. Main Outcomes and Measures: MCMs were assessed 1 year after birth by a committee blinded to type of exposure. Teratogenic outcomes across exposures were compared by random-effects logistic regression adjusting for potential confounders and prognostic factors. Results: A total of 10 121 prospective pregnancies exposed to ASM monotherapy met eligibility criteria. Of those, 9840 were exposed to the 8 most frequently used ASMs. The 9840 pregnancies occurred in 8483 women (mean [range] age, 30.1 [14.1-55.2] years). MCMs occurred in 153 of 1549 pregnancies for valproate (9.9%; 95% CI, 8.5%-11.5%), 9 of 142 for phenytoin (6.3%; 95% CI, 3.4%-11.6%), 21 of 338 for phenobarbital (6.2%; 95% CI, 4.1%-9.3%), 121 of 2255 for carbamazepine (5.4%; 95% CI, 4.5%-6.4%), 10 of 204 for topiramate (4.9%; 95% CI, 2.7%-8.8%), 110 of 3584 for lamotrigine (3.1%; 95% CI, 2.5%-3.7%), 13 of 443 for oxcarbazepine (2.9%; 95% CI, 1.7%-5.0%), and 33 of 1325 for levetiracetam (2.5%; 95% CI, 1.8%-3.5%). For valproate, phenobarbital, and carbamazepine, there was a significant increase in the prevalence of MCMs associated with increasing dose of the ASM. Overall prevalence of MCMs decreased from 6.1% (153 of 2505) during the period 1998 to 2004 to 3.7% (76 of 2054) during the period 2015 to 2022. This decrease over time was significant in univariable logistic analysis but not after adjustment for changes in ASM exposure pattern. Conclusions and Relevance: Of all ASMs with meaningful data, the lowest prevalence of MCMs was observed in offspring exposed to levetiracetam, oxcarbazepine, and lamotrigine. Prevalence of MCMs was higher with phenytoin, valproate, carbamazepine, and phenobarbital, and dose dependent for the latter 3 ASMs. The shift in exposure pattern over time with a declining exposure to valproate and carbamazepine and greater use of lamotrigine and levetiracetam was associated with a 39% decline in prevalence of MCMs, a finding that has major public health implications.

Toxic optic neuropathy associated with lamotrigine and levetiracetam dual therapy.

We report the case of an early adolescent male on lamotrigine and levetiracetam therapy with a 1-month history of progressive, bilateral, painless visual loss which resolved on cessation of lamotrigine. To our knowledge, we present the first case of lamotrigine and levetiracetam dual therapy associated with toxic optic neuropathy, supported by electrophysiology and optical coherence tomography (OCT) changes. Electrophysiology findings were consistent with retinal ganglion cell dysfunction, with bilateral optic nerve involvement. Macula OCT showed mild retinal ganglion cell loss in all inner quadrants bilaterally. This case highlights the importance of asking patients with epilepsy treated with lamotrigine and levetiracetam about visual problems and considering early dose reduction or cessation of treatment.

Risk of Autism after Prenatal Topiramate, Valproate, or Lamotrigine Exposure.

BACKGROUND: Maternal use of valproate during pregnancy has been associated with an increased risk of neurodevelopmental disorders in children. Although most studies of other antiseizure medications have not shown increased risks of these disorders, there are limited and conflicting data regarding the risk of autism spectrum disorder associated with maternal topiramate use. METHODS: We identified a population-based cohort of pregnant women and their children within two health care utilization databases in the United States, with data from 2000 through 2020. Exposure to specific antiseizure medications was defined on the basis of prescription fills from gestational week 19 until delivery. Children who had been exposed to topiramate during the second half of pregnancy were compared with those unexposed to any antiseizure medication during pregnancy with respect to the risk of autism spectrum disorder. Valproate was used as a positive control, and lamotrigine was used as a negative control. RESULTS: The estimated cumulative incidence of autism spectrum disorder at 8 years of age was 1.9% for the full population of children who had not been exposed to antiseizure medication (4,199,796 children). With restriction to children born to mothers with epilepsy, the incidence was 4.2% with no exposure to antiseizure medication (8815 children), 6.2% with exposure to topiramate (1030 children), 10.5% with exposure to valproate (800 children), and 4.1% with exposure to lamotrigine (4205 children). Propensity score-adjusted hazard ratios in a comparison with no exposure to antiseizure medication were 0.96 (95% confidence interval [CI], 0.56 to 1.65) for exposure to topiramate, 2.67 (95% CI, 1.69 to 4.20) for exposure to valproate, and 1.00 (95% CI, 0.69 to 1.46) for exposure to lamotrigine. CONCLUSIONS: The incidence of autism spectrum disorder was higher among children prenatally exposed to the studied antiseizure medications than in the general population. However, after adjustment for indication and other confounders, the association was substantially attenuated for topiramate and lamotrigine, whereas an increased risk remained for valproate. (Funded by the National Institute of Mental Health.).

Association of antiseizure medications and adverse cardiovascular events: A global health federated network analysis.

OBJECTIVE: A diagnosis of epilepsy has been associated with adverse cardiovascular events (CEs), but the extent to which antiseizure medications (ASMs) may contribute to this is not well understood. The aim of this study was to compare the risk of adverse CEs associated with ASM in patients with epilepsy (PWE). METHODS: A retrospective case-control cohort study was conducted using TriNetX, a global health federated network of anonymized patient records. Patients older than 18 years, with a diagnosis of epilepsy (International Classification of Diseases, 10th Revision code G40) and a medication code of carbamazepine, lamotrigine, or valproate were compared. Patients with cardiovascular disease prior to the diagnosis of epilepsy were excluded. Cohorts were 1:1 propensity score matched (PSM) according to age, sex, ethnicity, hypertension, heart failure, atherosclerotic heart disease, atrial and cardiac arrythmias, diabetes, disorders of lipoprotein metabolism, obesity, schizophrenia and bipolar disorder, medications, and epilepsy classification. The primary outcome was a composite of adverse CEs (ischemic stroke, acute ischemic heart disease, and heart failure) at 10 years. Cox regression analyses were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) following 1:1 PSM. RESULTS: Of 374 950 PWE included; three cohorts were established after PSM: (1) carbamazepine compared to lamotrigine, n = 4722, mean age 37.4 years; (2) valproate compared to lamotrigine, n = 5478, mean age 33.9 years; and (3) valproate compared to carbamazepine, n = 4544, mean age 37.0 years. Carbamazepine and valproate use were associated with significantly higher risk of composite cardiovascular outcome compared to lamotrigine (HR = 1.390, 95% CI = 1.160-1.665 and HR = 1.264, 95% CI = 1.050-1.521, respectively). Valproate was associated with a 10-year higher risk of all-cause death than carbamazepine (HR = 1.226, 95% CI = 1.017-1.478), but risk of other events was not significantly different. SIGNIFICANCE: Carbamazepine and valproate were associated with increased CE risks compared to lamotrigine. Cardiovascular risk factor monitoring and careful follow-up should be considered for these patients.

The teratogenesis risk associated with antiseizure medication duotherapy in women with epilepsy.

PURPOSE: To investigate rates of occurrence of pregnancies associated with a foetal malformation (FM pregnancy rates) following simultaneous intrauterine exposure to two antiseizure medications in 524 pregnancies in women with epilepsy from the Australian Pregnancy Register who were treated simultaneously with various combinations and dosages of two antiseizure medications (duotherapy). RESULTS: FM pregnancy rates tended to be higher in those exposed simultaneously to two antiseizure medications, each of which was a statistically significant teratogen (valproate, topiramate, or carbamazepine), than when there was exposure to only one such teratogen. When there was exposure to only one such teratogen together with clonazepam or levetiracetam, for neither of which there was statistically significant evidence of heightened teratogenicity, the FM pregnancy rates also tended to be higher, but less so. When lamotrigine was the other component of the duotherapy with an established teratogen, FM pregnancy rates tended to be lower than that for the teratogen used as monotherapy. CONCLUSION: Leaving aside issues in relation to seizure control, our data suggest that it would be best to avoid using established teratogenic antiseizure medications (carbamazepine, valproate and topiramate) in combination with each other due to the increased FM risks. When combining an established teratogenic medication with a less teratogenic one, i.e. lamotrigine, levetiracetam or clonazepam, lamotrigine appears to be the safer option.

Lamotrigine-Induced Hemophagocytic Lymphohistiocytosis with DRESS.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a severe inflammatory reaction syndrome caused by genetic or acquired immune dysregulation. The majority of adult HLH cases are caused by tumors, rheumatic immune disorders, and infections. However, drug-induced HLH is rarely reported. METHODS: We report a case of HLH in an adult caused by the administration of lamotrigine, to our knowledge, only nine other cases of lamotrigine-associated HLH have been reported in adult patients. RESULTS: After discontinuing lamotrigine and using steroid hormones for the HLH, the patient's condition has been brought under control. CONCLUSIONS: This case confirms that dexamethasone is also effective for drug-induced HLH. Usually, after discontinuing the relevant medications, there is no need for further maintenance treatment.

Neurodevelopmental outcomes after prenatal exposure to lamotrigine monotherapy in women with epilepsy: a systematic review and meta-analysis.

BACKGROUND: Lamotrigine has become one of the most commonly prescribed antiseizure medications (ASM) in epileptic women during pregnancy and therefore requires regular updates regarding its safety. The aim of this study was to estimate the association between in utero exposure to lamotrigine monotherapy and the occurrence of neurodevelopmental outcomes. METHODS: All comparative studies assessing the occurrence of neurodevelopmental outcomes after epilepsy-indicated lamotrigine monotherapy exposure during pregnancy were searched. First, references were identified through a snowballing approach, then, through electronic databases (Medline and Embase) from 2015 to June 2022. One investigator evaluated study eligibility and extracted data and a second independent investigator reviewed the meta-analysis (MA). A systematic review and random-effects model approach were performed using a collaborative WEB-based meta-analysis platform (metaPreg.org) with a registered protocol (osf.io/u4gva). RESULTS: Overall, 18 studies were included. For outcomes reported by at least 4 studies, the pooled odds ratios and 95% confidence interval obtained with the number of exposed (N1) and unexposed children (N0) included were: neurodevelopmental disorders as a whole 0.84 [0.66;1.06] (N1 = 5,271; N0 = 22,230); language disorders or delay 1.16 [0.67;2.00] (N1 = 313; N0 = 506); diagnosis or risk of ASD 0.97 [0.61;1.53] (N1 = at least 5,262; N0 = 33,313); diagnosis or risk of ADHD 1.14 [0.75;1.72] (N1 = at least 113; N0 = 11,530) and psychomotor developmental disorders or delay 2.68 [1.29-5.56] (N1 = 163; N0 = 220). The MA of cognitive outcomes included less than 4 studies and retrieved a significant association for infants exposed to lamotrigine younger than 3 years old but not in the older age groups. CONCLUSION: Prenatal exposure to lamotrigine monotherapy is not found to be statistically associated with neurodevelopmental disorders as a whole, language disorders or delay, diagnosis or risk of ASD and diagnosis or risk of ADHD. However, the MA found an increased risk of psychomotor developmental disorders or delay and cognitive developmental delay in less than 3 years old children. Nevertheless, these findings were based exclusively on observational studies presenting biases and on a limited number of included children. More studies should assess neurodevelopmental outcomes in children prenatally exposed to lamotrigine.

Anticonvulsant Agents for Treatment of Restless Legs Syndrome: A Case Report With Lamotrigine and a Review of the Literature.

INTRODUCTION: Restless Legs Syndrome (RLS) is a neurological disorder primarily treated with pregabalin and gabapentin, followed by dopamine agonists later in the process due to the risk of augmenting RLS symptoms. In addition, clinical reports have disclosed varying degrees of success employing other agents in patients unresponsive to traditional agents. Here, we present a patient who had success in the reduction of RLS symptoms with lamotrigine, a broad-spectrum anticonvulsant. Previously, lamotrigine had been used in 2 trials with successful treatment of RLS. CASE REPORT: We present a 58-year-old right-handed lady with long-standing history of smoking, hypertension, dyslipidaemia, prediabetes, gastro-esophageal reflux disease, asthma, strabismus, uterine cancer, severe and debilitating course of RLS accompanied by unexplained deterioration. The patient initially demonstrated abnormal sensation in all her limbs, which worsened with radiotherapy treatment, and was eventually diagnosed with RLS based on the diagnostic criteria. Subsequent examinations were unremarkable and revealed no further explanation for the deterioration of the RLS symptoms. While the complexity of the patient's medical history had exposed her to a variety of medications, she reported that only lamotrigine, in addition to her original regimen of methadone and pramipexole, offered significant symptomatic relief. It must be noted that no adverse side effects, including impulse-control disorder, were reported by the patient. CONCLUSIONS: We present a case of a woman whose deteriorating symptoms of RLS were successfully alleviated by the administration of lamotrigine. This is only the third case in the literature to have successfully utilized lamotrigine as a treatment option for RLS.

Time-Course Changes in Lamotrigine Concentration after Addition of Valproate and the Safety and Long-Term Tolerability of Lamotrigine-Valproate Combination Therapy.

The aim of this study was to evaluate the time-course changes in lamotrigine (LTG) concentration after addition of valproate (VPA) and the safety and tolerability of the combination therapy. We reviewed our therapeutic drug monitoring (TDM) database and found 345 patients on LTG who received add-on therapy with VPA. VPA had been added at least 12 weeks after patients finished stepwise LTG titration. Also, we retrospectively evaluated the LTG concentration after addition of VPA and the safety and long-term tolerability of LTG-VPA combination therapy. Plasma LTG concentration increased more than 1.5-fold within 15 d of addition of VPA and reached a peak at 30 d. The rate of increase in LTG concentration occurred in a VPA concentration-dependent manner. During the first 120 d after addition of VPA, adverse events were reported by 58 patients (16.8%), but no patient developed cutaneous reactions. Kaplan-Meier analysis showed estimated retention rates for LTG-VPA combination therapy of 74.5% at 5 years. At 5 years, the mean concentration of LTG was 11.1 µg/mL (43.3 µmol/L). Because addition of VPA leads to a marked increase in LTG concentration over a short period, TDM for LTG should be performed at the earliest from 14 d after starting VPA. At 120 d after starting VPA therapy, the higher LTG concentration due to addition of VPA is not associated with an increased risk of cutaneous reactions. Although LTG-VPA combination therapy increases LTG concentration, it is well tolerated and has a high long-term retention rate.

Leukopenia associated with lamotrigine initiation after COVID-19 vaccine booster: A case report and literature review.

Adverse lamotrigine effects are more likely with concomitant use of antiepileptic drugs, rapid dose titration, and multiple drug use, highlighting the importance of measuring its concentration. Here, lamotrigine was administered the day after the third mRNA vaccination to a 20-year-old bipolar woman with these risk factors. Leukopenia occurred on day 12 without rapid concentration increase, but leukocytes gradually recovered after 22 weeks without discontinuation of lamotrigine. The second mRNA vaccination did not induce leukopenia. Possibly, a synergetic immune response to simultaneous vaccination and lamotrigine caused leukopenia, which recovered as the response weakened. Lamotrigine initiation immediately after mRNA vaccination may be a leukopenia risk factor.

Lamotrigine efficacy, safety, and tolerability for women of childbearing age with bipolar I disorder: Meta-analysis from four randomized, placebo-controlled maintenance studies.

This meta-analysis investigated the efficacy, safety, and tolerability of lamotrigine versus placebo in preventing relapse and recurrence of mood episodes in women of childbearing age with bipolar I disorder. Following up to 16 weeks' open-label lamotrigine treatment, responders were randomized to double-blind treatment, including lamotrigine 100-400 mg/day or placebo, in four trials of up to 76 weeks. Women aged 18-45 years who received ≥ 1 dose of study treatment and had ≥ 1 efficacy assessment in the double-blind phase were pooled for efficacy analysis. The primary outcome was median time to intervention for any mood episode (TIME). Of 717 eligible women in the open-label phase, 287 responded and were randomized to lamotrigine (n = 153) or placebo (n = 134). The randomized group had a mean (SD) of 2.0(2.02) manic and 2.5(2.02) depressive episodes in the 3 years before screening. Median TIME was 323 days with lamotrigine and 127 days with placebo (HR 0.69; 95% CI 0.49, 0.96; p = 0.030). Lamotrigine delayed time to intervention for any depressive episode (HR 0.59; 95% CI 0.39, 0.90; p = 0.014) with no treatment difference for manic episodes (HR 0.91; 95% CI 0.52, 1.58; p = 0.732). 2/717 (< 1%) participants experienced serious rash-related adverse events (AEs) during the open-label phase, and 52/717 (7%) had non-serious rash-related events leading to study withdrawal. Incidence of AEs and AEs leading to withdrawal were similar between lamotrigine and placebo groups. Lamotrigine delayed relapse and recurrence of mood episodes, largely by preventing depressive episodes, and was well tolerated in women of childbearing age.

Periportal necrosis and successful liver transplantation following Lamotrigine drug-induced liver injury in a child.

Lamotrigine is one of the most prescribed antiepileptics in children and a well-known cause of drug-induced liver injury (DILI). The typical presentation usually includes a drug rash with eosinophilia and systemic symptoms (DRESS syndrome). Cases are typically mild and self-limiting, requiring supportive care only. We report a severe Lamotrigine-induced DILI with a non-typical presentation with hyperammonaemia and rapid clinical deterioration. We present a literature review exploring contributing factors, transplant considerations and liver histology. Histology showed periportal necrosis, which is recognised as a pattern of DILI but has not been previously described with Lamotrigine. Our patient proceeded to transplant and is the first reported liver transplant for Lamotrigine DILI in a child. A directed and rapid diagnostic approach is crucial to avoid delays and rule out multisystemic metabolic and genetic conditions that preclude liver transplantation.

Lamotrigine use and potential for adverse cardiac effects: A retrospective evaluation in a Veteran population.

OBJECTIVE: To identify the impact of lamotrigine (LTG) on cardiac rhythm and conduction abnormalities for Veterans, an especially vulnerable population. BACKGROUND: In October 2020 the US Food and Drug Administration (FDA) added a new warning to the label of lamotrigine (Lamictal™) regarding its potential to cause cardiac rhythm and conduction abnormalities [1]. This warning came following in vitro data which suggested Class IB antiarrhythmic effects occurring at clinically achievable concentrations of lamotrigine [2]. However, it is unclear whether the in vitro findings will result in adverse clinical outcomes. Our objective was to assess for evidence for adverse clinical outcomes in a vulnerable population and examine for subtler signs of an association between lamotrigine and cardiac rhythm disturbances. METHODS: A retrospective chart review was conducted using records between 10-01-2017 and 07-06-2021, identifying patients at the William S. Middleton Memorial Veterans Hospital who were prescribed lamotrigine. Data collected included: dates of lamotrigine initiation or discontinuation, lamotrigine dosing over the time of the prescription and maximum lamotrigine dose, any cardiac-related ICD-10-CM codes or a history of a cardiology appointment, EKGs with any abnormalities or changes, any concomitantly prescribed medications with known potential to cause cardiac abnormalities, any cardiac deaths. This retrospective chart review was approved by the University of Wisconsin-Madison Institutional Review Board. RESULTS: Two hundred and thirty-three (189 male) patients with a lamotrigine prescription and 41.2 % (n = 96) of these patients had an EKG performed while prescribed lamotrigine. The average age of patients was 64.3 ± 13.0 (range 29 to 90) years and mean maximum lamotrigine daily dose was 250.8 ± 148.2 mg (range 25 to 800 mg). Nearly half (47.9 %, 46/96) of the patients were prescribed a concomitant sodium channel blocking medication in addition to lamotrigine. Eighty-four of the patients (87.5 %, 84/96) had a cardiac diagnosis, while 12 (12.5 %, 12/96) did not. A total of 12 deaths occurred within the review period, with two cardiac deaths from congestive heart failure. Four cases did not have information on cause of death. No LTG-associated cardiac adverse effects were noted as part of clinical care, though rash was noted in 5 cases. A total of 7 (7.3 %, 7/96) patients were found to have EKG abnormalities potentially related to lamotrigine, including 7.1 % (6/84) of those with a cardiac diagnosis and 8.3 % (1/12) of those without a cardiac diagnosis. CONCLUSIONS: While recent FDA warnings have suggested caution regarding cardiac complications associated with lamotrigine based on in vitro studies, the clinical implications are uncertain. Despite selecting a particularly vulnerable population, this retrospective chart review did not identify any deaths due to cardiac rhythm or conduction causes, nor demonstrate unambiguous cardiac complications related to lamotrigine. Even using permissive criteria (including any prolonged PR or QTc) to examine for subtle effects, only a low incidence (<10 %) of potential complications was found. Broader implications of this study are limited by the number of patients included and the retrospective nature of the study. Therefore, further studies are warranted to evaluate a link between cardiac complications and the use of lamotrigine, including the role of concomitant medications such as other sodium channel blocking agents and psychotropic medications.

Antiepileptogenic Effects of Anakinra, Lamotrigine and Their Combination in a Lithium-Pilocarpine Model of Temporal Lobe Epilepsy in Rats.

Temporal lobe epilepsy is a common, chronic disorder with spontaneous seizures that is often refractory to drug therapy. A potential cause of temporal lobe epilepsy is primary brain injury, making prevention of epileptogenesis after the initial event an optimal method of treatment. Despite this, no preventive therapy for epilepsy is currently available. The purpose of this study was to evaluate the effects of anakinra, lamotrigine, and their combination on epileptogenesis using the rat lithium-pilocarpine model of temporal lobe epilepsy. The study showed that there was no significant difference in the number and duration of seizures between treated and untreated animals. However, the severity of seizures was significantly reduced after treatment. Anakinra and lamotrigine, alone or in combination, significantly reduced neuronal loss in the CA1 hippocampus compared to the control group. However, the drugs administered alone were found to be more effective in preventing neuron loss in the hippocampal CA3 field compared to combination treatment. The treatment alleviated the impairments in activity level, exploratory behavior, and anxiety but had a relatively weak effect on TLE-induced impairments in social behavior and memory. The efficacy of the combination treatment did not differ from that of anakinra and lamotrigine monotherapy. These findings suggest that anakinra and lamotrigine, either alone or in combination, may be clinically useful in preventing the development of histopathological and behavioral abnormalities associated with epilepsy.

A novel approach for pharmacological substantiation of safety signals using plasma concentrations of medication and administrative/healthcare databases: A case study using Danish registries for an FDA warning on lamotrigine.

PHARMACOM-EPI is a novel framework to predict plasma concentrations of drugs at the time of occurrence of clinical outcomes. In early 2021, the U.S. Food and Drug Administration (FDA) issued a warning on the antiseizure drug lamotrigine claiming that it has the potential to increase the risk of arrhythmias and related sudden cardiac death due to a pharmacological sodium channel-blocking effect. We hypothesized that the risk of arrhythmias and related death is due to toxicity. We used the PHARMACOM-EPI framework to investigate the relationship between lamotrigine's plasma concentrations and the risk of death in older patients using real-world data. Danish nationwide administrative and healthcare registers were used as data sources and individuals aged 65 years or older during the period 1996 - 2018 were included in the study. According to the PHARMACOM-EPI framework, plasma concentrations of lamotrigine were predicted at the time of death and patients were categorized into non-toxic and toxic groups based on the therapeutic range of lamotrigine (3-15 mg/L). Over 1 year of treatment, the incidence rate ratio (IRR) of all-cause mortality was calculated between the propensities score matched toxic and non-toxic groups. In total, 7286 individuals were diagnosed with epilepsy and were exposed to lamotrigine, 432 of which had at least one plasma concentration measurement The pharmacometric model by Chavez et al. was used to predict lamotrigine's plasma concentrations considering the lowest absolute percentage error among identified models (14.25 %, 95 % CI: 11.68-16.23). The majority of lamotrigine associated deaths were cardiovascular-related and occurred among individuals with plasma concentrations in the toxic range. The IRR of mortality between the toxic group and non-toxic group was 3.37 [95 % CI: 1.44-8.32] and the cumulative incidence of all-cause mortality exponentially increased in the toxic range. Application of our novel framework PHARMACOM-EPI provided strong evidence to support our hypothesis that the increased risk of all-cause and cardiovascular death was associated with a toxic plasma concentration level of lamotrigine among older lamotrigine users.

Investigation of cardiac arrhythmia events in patients treated with lamotrigine: FDA adverse event reporing system analysis.

OBJECTIVES: In October 2020 and March 2021, the U.S. Food and Drug Administration (FDA) classified lamotrigine as a class IB antiarrhythmic, announcing an increased risk of heart rhythm problems. We sought to investigate the nature of the arrhythmia signal with lamotrigine use compared to anticonvulsants with sodium-blocking and non-sodium-blocking mechanisms. METHODS: This retrospective pharmacovigilance case-non-case study used disproportionality analysis to detect signals of adverse reaction of interest reported with lamotrigine to the FDA Adverse Event Reporting System (FAERS) between 1998 and 2022. Our regression model adjusted for interacting concomitant medications. Sensitivity analyses included stratifying by indication and publication date. RESULTS: Overall, 2917 cases of heart rhythm problems with anticonvulsants were analyzed (1557 female [58.4%] and 1109 male [41.6%]). The mean age ± standard deviation (SD) was 43 ± 19, the groups did not differ significantly by age. Forty cases (7.91%) in the epileptic indication included more than one concomitant medication that influences cardiac conduction. The disproportionality signal for cardiac arrest did not differ for lamotrigine compared with other anticonvulsants, adjusted reporting odds ratio (adj.ROR, .88; 95% CI, .59-1.29) in the epileptic indication. A significantly lower reporting risk for bradyarrhythmia was identified with lamotrigine users in the epileptic population, (adj.ROR, .45; 95% confidence interval [CI], .29-.68). The psychiatric indication demonstrated a sixfold reporting risk for cardiac arrest compared to the epileptic indication. Concomitant medications that affect cardiac conduction, as well as reports on overdose and suicide attempts, were significant variables in psychiatric patients (ROR, 2.45; 95% CI, 2.21-2.71) and (ROR, 1.44; 95% CI, 1.34-1.55), respectively. SIGNIFICANCE: Our results do not support a significant difference in the reporting risk for cardiac arrest, syncope, tachyarrhythmia, and bradyarrhythmia with lamotrigine in the epileptic indication. Signals of cardiac arrest in lamotrigine could be explained by confounding factors in the psychiatric indication, such as greater concomitant use of medications with cardiac adverse events, and greater reports on overdose and suicide attempts. We recommend that patients with polypharmacy undergo clinical and electrocardiographic monitoring. We illustrate the importance of examining signals for separate indications.