Lamotrigine-associated rash: to rechallenge or not to rechallenge?

Black-Box Warnings of Antiseizure Medications: What is Inside the Box?

Antiseizure medications can cause serious adverse reactions and have deleterious drug interactions that often complicate the clinical management of patients. When the US Food and Drug Administration (FDA) wants to alert healthcare providers and patients about the risk of potentially serious or fatal drug reactions, the FDA requires the manufacturers of these medications to format these warnings within a "black-box" border, and prominently display this box on the first section of the package insert; such warnings are called "black-box warnings (BBWs)". The BBW is a way for the FDA to urge physicians to evaluate patients more rigorously and carefully weigh the risks and benefits, before prescribing medication that has the potential to cause serious adverse reactions, and to formulate a plan for close monitoring during therapy. The FDA BBW provides the extra layer of safety but many healthcare providers fail to comply with these warnings. Currently, there are 26 FDA-approved antiseizure medications in the US market, 38% of which have received BBWs, and most of the antiseizure medications with BBWs are older-generation drugs. Some antiseizure medications have multiple BBWs; for example, valproic acid has three BBWs including hepatotoxicity, fetal risk, and pancreatitis, carbamazepine has BBWs of serious skin and hematological reactions, and felbamate also has two BBWs including hepatic failure and aplastic anemia. The purpose of this review is to provide insight into each BBW received by antiseizure medications and discuss the FDA recommendations for evaluating the drug benefit/risk, and for monitoring parameters before the initiation of and during treatment.

Distribution of HLA-B Alleles and Haplotypes in Qatari: Recommendation for Establishing Pharmacogenomic Markers Screening for Drug Hypersensitivity

Human leukocyte antigen (HLA) proteins are present at the cellular surface of antigen-presenting cells and play a crucial role in the adaptive immune response. Class I genes, specifically certain HLA-B alleles, are associated with adverse drug reactions (ADRs) and are used as pharmacogenetic markers. Although ADRs are a common causes of hospitalization and mortality, the data on the prevalence of HLA-B pharmacogenetics markers in Arab countries are scarce. In this study, we investigated the frequencies of major HLA-B pharmacogenomics markers in the Qatari population. Next-generation sequencing data from 1,098 Qatari individuals were employed for HLA-B typing using HLA-HD version 1.4.0 and IPD-IMGT/HLA database. In addition, HLA-B pharmacogenetics markers were obtained from the HLA Adverse Drug Reaction Database. In total, 469 major HLA-B pharmacogenetic markers were identified, with HLA-B*51:01 being the most frequent pharmacogenetic marker (26.67%) in the Qatari population. Moreover, HLA-B*51:01 is associated with phenytoin- and clindamycin-induced ADRs. The second most frequent pharmacogenetic marker was the HLA-B*58:01 allele (6.56%), which is associated with allopurinol-induced ADRs. The third most frequent pharmacogenetic marker was the HLA-B*44:03 allele, which is associated with phenytoin-induced ADRs. The establishment of a pharmacogenetics screening program in Qatar for cost effective interventions aimed at preventing drug-induced hypersensitivity can be aided by the highly prevalent HLA-B pharmacogenetic markers detected here.

Impact of Selected Initial Titration Schedules on Safety and Long-Term Effectiveness of Lamotrigine for the Treatment of Mood Disorders

PURPOSE

Lamotrigine (LTG) is used for treatment of mood disorders, but it is associated with the risk of rash occurrence in the initial administration phase. Although slow titration reduces this risk, its effectiveness in the treatment of mood disorders has not been verified. The effects of titration method on the safety and effectiveness of LTG for the treatment of mood disorders were examined in this study.

METHODS

This retrospective cohort study included 312 patients with mood disorders who underwent initiation of LTG therapy. Data regarding baseline demographics, titration schedules, concomitant medications, and time to and cause of discontinuation of LTG were collected. A multivariate analysis was used to evaluate the effects of the titration schedules. The 12-month effectiveness was also evaluated.

RESULTS

The 12-month discontinuation rate of LTG was 16.7%. The most frequent cause of discontinuation was development of a rash (47.7%, n = 312). Fast titration (adjusted odds ratio, 8.15) significantly increased the risk of rash development, and slow titration (adjusted odds ratio, 0.29) significantly decreased this risk. The time to all-cause discontinuation was not significantly different between the slow and standard titration groups (n = 303). After 12 months of treatment, the condition of 46.7% patients were rated much or very much improved using CGI-C.

CONCLUSIONS

Although slow titration of LTG reduces the occurrence of a rash, it is not more effective than standard titration in the long term. Optimizing the initial LTG titration schedule for patients with mood disorders is challenging.

Rash during lamotrigine treatment is not always drug hypersensitivity: A retrospective cohort study among children and adults

Purpose Cutaneous adverse drug reactions (cADRs) are a major cause of lamotrigine (LTG) discontinuation. Remarkable variation in their reported incidence suggests confounders and diverse terms and definitions. The aim of this study was to identify immunological cADRs and to throw light on classification and differential diagnoses in children and adults. Methods Hospital records of 2683 patients with epilepsy (1897 adults, 786 children) were retrospectively screened. Of these, 403 patients (236 adults, 167 children) with first time exposure to LTG were reviewed. Skin reactions were categorized into possible or probable cADRs due to LTG hypersensitivity, and other skin reactions (OSRs) unlikely to be caused by this mechanism. Results 29 of 403 patients (7.2%) reported emergent skin symptoms within 3 months of treatment with LTG of which 20 (5%: 5.9% adults, 3.6% children) were categorized as possible or probable cADRs. Concomitant infection appeared to be present in several cases, particularly in children. OSRs were found in 4.2% of the children using LTG, compared to 0.8% of the adults (p = 0.04). Conclusions Rash during the early phase of LTG treatment is not always drug hypersensitivity. Whenever skin symptoms occur, other potential causes should receive attention to avoid needless discontinuation, particularly in children. However, when early symptoms and signs of severe cADRs are suspected, LTG should promptly be discontinued.

Discovery of Vixotrigine: A Novel Use-Dependent Sodium Channel Blocker for the Treatment of Trigeminal Neuralgia

Drugs that block voltage-gated sodium channels (NaVs) have utility in treating conditions including pain, epilepsy, and cardiac arrhythmias and as anesthetics (Lancet Neurol.20109413424; Expert Opin. Ther. Pat.201020755779). The identification of compounds with improved efficacy and safety is a key aim for the discovery of improved NaV blocking drugs (Comprehensive Medicinal Chemistry III; (Elsevier, 2017; pp 131-175). We report the identification of a novel class of brain penetrant and voltage-gated sodium channel blockers, leading to the discovery of vixotrigine, a use-dependent sodium channel blocker with activity in in vivo models of pain. Vixotrigine has excellent physiocochemical properties for drug development, and both preclinical and clinical data support a safety profile suitable for potential use in neuropathic pain and other conditions. It has shown efficacy in a Phase II study for pain associated with trigeminal neuralgia.

Lamotrigine add-on therapy for drug-resistant generalised tonic-clonic seizures

BACKGROUND

This is an update of the Cochrane Review first published in 2010; it includes one additional study. Primary generalised tonic-clonic seizures are a type of generalised seizure. Other types of seizures include: absence, myoclonic, and atonic seizures. Effective control of tonic-clonic seizures reduces the risk of injury and death, and improves quality of life. While most people achieve seizure control with one antiepileptic drug, around 30% do not, and require a combination of antiepileptic drugs.

OBJECTIVES

To assess the effectiveness and tolerability of add-on lamotrigine for drug-resistant primary generalised tonic-clonic seizures.

SEARCH METHODS

For the latest update, we searched these databases on 19 March 2019: Cochrane Register of Studies (CRS) Web, MEDLINE Ovid, and the WHO International Clinical Trials Registry Platform (ICTRP). The CRS includes records from the Cochrane Epilepsy Group Specialized Register, CENTRAL, Embase, and ClinicalTrials.gov. We imposed no language restrictions. We also contacted GlaxoSmithKline, manufacturers of lamotrigine.

SELECTION CRITERIA

Randomised controlled parallel or cross-over trials of add-on lamotrigine for people of any age with drug-resistant primary generalised tonic-clonic seizures.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology; two review authors independently assessed trials for inclusion, evaluated risk of bias, extracted relevant data, and GRADE-assessed evidence. We investigated these outcomes: (1) 50% or greater reduction in primary generalised tonic-clonic seizure frequency; (2) seizure freedom; (3) treatment withdrawal; (4) adverse effects; (5) cognitive effects; and (6) quality of life. We used an intention-to-treat (ITT) population for all analyses, and presented results as risk ratios (RRs) with 95% confidence intervals (CIs); for adverse effects, we used 99% CIs to compensate for multiple hypothesis testing.

MAIN RESULTS

We included three studies (total 300 participants): two parallel-group studies and one cross-over study. We assessed varied risks of bias across studies; most limitations arose from the poor reporting of methodological details. We meta-analysed data extracted from the two parallel-group studies, and conducted a narrative synthesis for data from the cross-over study. Both parallel-group studies (270 participants) reported all dichotomous outcomes. Participants taking lamotrigine were almost twice as likely to attain a 50% or greater reduction in primary generalised tonic-clonic seizure frequency than those taking a placebo (RR 1.88, 95% CI 1.43 to 2.45; low-certainty evidence). The results between groups were inconclusive for the likelihood of seizure freedom (RR 1.55, 95% CI 0.89 to 2.72; very low-certainty evidence); treatment withdrawal (RR 1.20, 95% CI 0.72 to 1.99; very low-certainty evidence); and individual adverse effects: ataxia (RR 3.05, 99% CI 0.05 to 199.36); dizziness (RR 0.91, 99% CI 0.29 to 2.86; very low-certainty evidence); fatigue (RR 1.02, 99% CI 0.13 to 8.14; very low-certainty evidence); nausea (RR 1.60, 99% CI 0.48 to 5.32; very low-certainty evidence); and somnolence (RR 3.73, 99% CI 0.36 to 38.90; low-certainty evidence). The cross-over trial (26 participants) reported that 7/14 participants with generalised tonic-clonic seizures experienced a 50% or greater reduction in seizure frequency with add-on lamotrigine compared to placebo. The authors reported four treatment withdrawals, but did not specify during which treatment allocation they occurred. Rash (seven lamotrigine participants; zero placebo participants) and fatigue (five lamotrigine participants; zero placebo participants) were the most frequently reported adverse effects. None of the included studies measured cognition. One parallel-group study (N = 153) evaluated quality of life. They reported inconclusive results for the overall quality of life score between groups (P = 0.74).

AUTHORS' CONCLUSIONS

This review provides insufficient information to inform clinical practice. Low-certainty evidence suggests that lamotrigine reduces the rate of generalised tonic-clonic seizures by 50% or more. Very low-certainty evidence found inconclusive results between groups for all other outcomes. Therefore, we are uncertain to very uncertain that the results reported are accurate, and suggest that the true effect could be grossly different. More trials, recruiting larger populations, over longer periods, are necessary to determine lamotrigine's clinical use.

Risks associated with lamotrigine prescription: a review and personal observations

OBJECTIVES:

To detail some serious lamotrigine side effects and their management, and raise awareness about the possible lack of quality control of some brands of lamotrigine.

METHODS:

A literature review is provided and some personal observations added.

RESULTS:

While most psychiatrists are aware of the risks of Stevens-Johnson syndrome (SJS), awareness of two other serious side effects - toxic epidermal necrosis (TEN) and drug-related eosinophilia and systemic symptoms (DRESS) - is seemingly lower. Awareness that failure to respond to lamotrigine and that the prevalence of serious side effects may reflect poor quality control of some preparations is also less well recognized.

CONCLUSIONS:

While lamotrigine may be retrialled at a lower dose escalation rate following some skin reactions, it should not be recommenced following a SJS, TEN or DRESS reaction. Prescribers should be aware of quality control concerns about some available brands of lamotrigine.

Korean Medication Algorithm Project for Bipolar Disorder 2018 (KMAP-BP 2018): Fourth Revision

Objective

The Korean Medication Algorithm Project for Bipolar Disorder (KMAP-BP) was first published in 2002 through an expert consensus of opinion, and updated in 2006, 2010, and 2014. This study constitutes the fourth revision of the KMAP-BP.

Methods

A 50-item questionnaire was used to obtain the consensus of experts regarding pharmacological treatment strategies for various phases of adult bipolar disorder and six items for pediatric bipolar disorder. The review committee included 84 Korean psychiatrists and 43 child and adolescent psychiatry experts.

Results

The preferred first-step strategies for acute mania were the combination of a mood stabilizer (MS) and an atypical antipsychotic (AAP), MS monotherapy, and AAP monotherapy. A combination of a MS and an AAP, and AAP monotherapy were preferred for psychotic mania. The first-step strategies for mild to moderate bipolar depression were monotherapy with MS, AAP, or lamotrigine (LMT), and the combination of a MS and an AAP or LMT, or a combination of an AAP and LMT. The combination of two among a MS, AAP, and LMT were preferred for non-psychotic severe depression. A combination of a MS and an AAP or the combination of an AAP with an antidepressant or LMT were the first-line options for psychotic severe depression.

Conclusion

The recommendations of the KMAP-BP 2018 have changed from the previous version by reflecting recent developments in pharmacotherapy for bipolar disorder. KMAP-BP 2018 provides clinicians with a wealth of information regarding appropriate strategies for treating patients with bipolar disorder.

Rechallenge of lamotrigine after development of rash

Lamotrigine (LTG) is associated with the potential for a life-threatening rash (eg, Stevens-Johnson syndrome or toxic epidermal necrolysis). The incidence has been linked to rapid titration and an interaction with valproic acid that can increase the level of LTG. Providers often have difficulty discriminating between serious versus benign rashes, and the package insert recommends discontinuing the medication at the first sign of a rash. Therefore, many patients end up being taken off LTG when it may have been effective for them. We present a case where LTG is reintroduced with a faster initial titration than what is noted in the literature after development of a rash. This case is also unique in that the patient had been on LTG for years prior to emergence of the rash and demonstrates that retrials can be successful.

Association between HLA-DRB1*0405, -DQB1*0401 and -DQA1*0303 alleles and lamotrigine-induced cutaneous adverse drug reactions. A pilot case-control study from Japan

BACKGROUND

Human leukocyte antigen (HLA) genotypes in lamotrigine -induced (LTG-induced) cutaneous adverse drug reactions (cADRs) have been described in several reports but controversy remains even for a given ethnic group. We attempted to clarify a possible association between LTG-induced cADRs and HLA alleles in Japanese patients.

METHOD

Sixteen subjects, including eight patients with LTG-induced cADRs and eight LTG-tolerant controls were included in this study. All eight patients with LTG-induced cADRs gave positive results in a drug-induced lymphocyte stimulation test (DLST) with LTG. We performed HLA-typing for HLA-A, -B, -C, -DRB1, -DQA1, -DQB1, -DPA1 and -DPB1, using PCR with sequence-specific oligonucleotide probes and multiple analyte profiling (xMAP) technology (Luminex System; Luminex Corporation, Austin, TX). We examined differences between allele frequencies in our two groups of subjects and the allele frequencies in the general Japanese population.

RESULTS

The frequencies of HLA-DRB1*0405, and HLA-DQB1*0401 alleles were higher in our LTG-cADRs patients than the reference frequencies in the general Japanese population. We also detected HLA-DQA1*0303 frequently in our LTG-cADRs patients, but data for this allele in the Japanese population was not available. Our observation was presumably due to the linkage disequilibrium among the three alleles. The haplotype frequency of HLA-DRB1*0405, DQB1*0401 and DQA1*0303 in our LTG-cADRs subjects was also different from the corresponding haplotype frequency in the database for the Japanese population and the difference was statistically significant. One patient with the HLA-DRB1*0405, -DQB1*0401 and DQA1*0303 haplotype was safely re-treated with LTG after results of a DLST with LTG ceased to be positive about 4 months after discontinuation of LTG.

LIMITATIONS

Our analysis included only 16 patients. Associations between LTG-induced cADRs and specific HLA loci will have to be confirmed in larger studies.

CONCLUSIONS

LTG-induced cADRs are associated with HLA-DRB1*0405, -DQB1*0401 and -DQA1*0303.

Managing the side effects associated with commonly used treatments for bipolar depression

BACKGROUND

The most commonly used pharmacologic therapies for bipolar depression are mood stabilizers, atypical antipsychotics, and antidepressants. This paper reviews common side effects associated with these medications and provides recommendations for managing adverse medication effects in clinical practice.

METHODS

Narrative review based on literature searches of Medline and evidence-based treatment guidelines for agents that have been approved by the US Food and Drug Administration and/or are commonly used to treat bipolar depression.

RESULTS

Side effects of bipolar depression pharmacotherapies are common and vary by medication, with weight gain, metabolic dysregulation, sedation/somnolence, and akathisia among those observed most frequently. These adverse events (weight gain and sedation/somnolence, in particular) negatively affect treatment adherence in patients with bipolar disorder. Furthermore, endocrine and metabolic comorbidities, weight gain, and obesity may reduce the likelihood of positive clinical responses to pharmacologic therapies. Clinicians may consider switching patients to bipolar depression medication(s) with a lower propensity for sedation or adverse metabolic effects. Lifestyle modification (e.g., dietary changes, exercise) is an important component in the treatment of weight gain/obesity, dyslipidemia, hypertension, and hyperglycemia; in addition, a wide range of medications are available as therapeutic options for patients in whom non-pharmacologic management strategies are insufficient. The use of adjunctive medication may also reduce treatment-related sedation and somnolence.

LIMITATIONS

The selection of relevant studies from the literature search relied primarily on the author's expertise in the area of bipolar depression and knowledge of the issues addressed.

CONCLUSION

Successful treatment of bipolar depression extends beyond managing mood symptoms to also monitoring adverse medication events and managing associated medical disorders.

Erythema multiforme vs. DRESS syndrome associated with the combined use of lamotrigine and cyclobenzaprine: a case report

Lamotrigine is FDA-approved as a maintenance treatment of bipolar disorder, but its common off-label uses include bipolar depression and antidepressant augmentation in patients with major depressive disorder. Among other adverse effects, cutaneous reactions, particularly erythema multiforme, are cited as concerns during treatment with this medication. In order to minimize the risk of cutaneous side effect, efforts have been made to identify factors associated with a higher rate of lamotrigine-induced rash. We report here a case of Drug Reaction with Eosinophilia and Systemic Symptoms apparently precipitated by the associated use of lamotrigine and cyclobenzaprine.