Stevens-Johnson syndrome due to concomitant use of lamotrigine and valproic acid

Whole-Exome Sequencing in Patients Affected by Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Reveals New Variants Potentially Contributing to the Phenotype

Background

Adverse drug reactions (ADRs) are frequent occurring events that can essentially be defined as harmful or unpleasant symptoms secondary to the use of a medicinal product. ADRs involve a wide spectrum of clinical manifestations ranging from minor itching and rash to life-threatening reactions. Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare ADRs. SJS-TEN may be considered a polygenic pathology due to additive/epistatic effects caused by sequence variants in numerous genes. Next-generation sequencing (NGS) represents a potentially interesting exploration tool in such scenario as it facilitates the simultaneous analysis of large genomic regions and genes at affordable cost.

Methods

The present study has involved using whole-exome sequencing (WES) for the first time on SJS-TEN patients. It involved robust and innovative multistep bioinformatics analysis focusing on 313 candidate genes potentially participating in the disease’s aetiology, specific drugs’ metabolism and gene regulation.

Results

We identified combinations of frequently occurring and rare variants that may contribute to the disease’s pathogenesis. Depending on the specific drug being taken, different variants (and alleles) in NAT2, CYP2D8, CYP2B6, ABCC2, UGT2B7 and TCF3 were identified as coherent candidates representing potential future markers for SJS-TEN.

Conclusion

The present study proposed and has described (for the first time) a large-scale genomic analysis of patients affected by SJS-TEN. The genes and variants identified represent relevant candidates potentially participating in the disease’s pathogenesis. Corroborating that proposed by others, we found that complex combinations of frequently occurring and rare variants participating in particular drug metabolism molecular cascades could be associated with the phenotype. TCF3 TF may be considered a coherent candidate for SJS-TEN that should be analysed in new cohorts of patients having ADRs.

Valproic acid and Stevens-Johnson syndrome: a systematic review of descriptive studies

Valproic acid (VPA) is a commonly used antiepileptic drug (AED). Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis are the rare but fatal cutaneous adverse drug reactions for VPA. We aimed to identify and critically evaluate all the literature of SJS in association with VPA and to describe the clinical features of the condition. A literature search was conducted in MEDLINE/PubMed from inception to December 2017 and updated in July 2018 without any restrictions, and the references of included studies were also searched. The descriptive studies discussing any patients who experienced SJS followed by the use of VPA alone or along with any other AED for its main indication were included. Two authors were independently involved in the study selection and data extraction. Disagreements were resolved by consensus or by the discussion with a third reviewer. A total of 19 studies including 17 case reports and two case series of 98 were included in the review. In all studies, the dose of VPA ranged from 100 mg/day to a maximum dose of 1,000 mg/day and was administered for indications including epilepsy, seizures, schizophrenic affective disorders, and bipolar disorder. The mortality seen with severe cutaneous adverse drug reactions can be decreased by immediate withdrawal of opposing medications, providing symptomatic relief, and offering supportive care, all of which are the mainstay of controlling the condition. It is essential for healthcare professionals to be aware of the importance of monitoring SJS or any other cutaneous reactions followed by the use of valproic acid even though the incidence is low, but it is injurious to the patient.

Cutaneous Adverse Drug Reactions to Lamotrigine and Human Leukocyte Antigen Typing in North Indian Patients: A Case Series

Cutaneous adverse drug reaction (cADR) has limited epidemiological data in India. The older antiepileptic drugs, i.e., carbamazepine, phenytoin, valproic acid, phenobarbitone, etc., induce severe cADRs that have a strong associated with human leukocyte antigen (HLA)-related genetic risk factors. There is also evidence of association of certain HLA alleles with lamotrigine (LTG)-induced cADRs, but this has not been reported in the Indian population. Here, we report case series of three patients with LTG-induced “Stevens-Johnson syndrome (SJS).” Their HLA-B typing was also performed which showed the presence of HLA-B*15:02 in one case with SJS.

Lamotrigine-induced severe cutaneous adverse reaction: Update data from 1999-2014

We systematically reviewed and analyzed published patients with Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) associated with lamotrigine therapy to identify characteristics of these reactions. We identified a total of 70 patients (42 SJS, five SJS/TEN, 23 TEN). The female to male ratio was 2.83:1 in the TEN group and 1.47:1 in the SJS group. Patients in the TEN group were younger than in the SJS group but this difference was not significant (28.35 versus 32.71 years, respectively; p=0.27). The median time to onset was 25.33 versus 18.42 days for SJS and TEN, respectively. The median dosage at onset was 36.46 versus 57.29mg, and final dosage 111.25 versus 97.92mg/day for SJS and TEN, respectively. The median final dosages did not significantly differ. Concomitant use of valproate acid was reported in 54.55% of the SJS patients and 50.00% of the TEN patients. Three fatal reactions were reported, of which two patients deteriorated rapidly and died within 12h of admission, indicating that this disease can develop rapidly before effective treatment. There was no significant difference between the SJS and TEN groups in any of the clinical factors examined which confirmed the opinion that SJS and TEN are part of a single disease spectrum.

Adverse drug reactions induced by valproic acid

Valproic acid is a widely-used first-generation antiepileptic drug, prescribed predominantly in epilepsy and psychiatric disorders. VPA has good efficacy and pharmacoeconomic profiles, as well as a relatively favorable safety profile. However, adverse drug reactions have been reported in relation with valproic acid use, either as monotherapy or polytherapy with other antiepileptic drugs or antipsychotic drugs. This systematic review discusses valproic acid adverse drug reactions, in terms of hepatotoxicity, mitochondrial toxicity, hyperammonemic encephalopathy, hypersensitivity syndrome reactions, neurological toxicity, metabolic and endocrine adverse events, and teratogenicity.

Toxic epidermal necrolysis due to lamotrigine in a pediatric patient

A 12-year-male child developed toxic epidermal necrolysis (TEN) probably due to lamotrigine. The patient was on antiepileptic therapy (sodium valproate and clonazepam) since 6–7 months, and lamotrigine was added in the regimen 1–2 months back. A serious cutaneous reaction is more likely to occur during the first 2 months of starting lamotrigine. The use of lamotrigine as an add-on to valproate may have precipitated the reaction. Other drugs were ruled out based on the incubation period of TEN. Drug interactions should be kept in mind with multiple antiepileptic therapies. The patient died because of the severity of reactions and delay in starting the treatment with steroids. One must be vigilant in early detection of the reaction.

Pharmacogenetic screening of carbamazepine-induced severe cutaneous allergic reactions

Recent studies associated the HLA-B 1502 allele with carbamazepine (CBZ)-induced Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) in patients from China, Thailand and Malaysia. No association has been found in patients from Europe or Japan. Linkage summary reports from East and South-east Asia predict a highly significant odds ratio (OR) of 84.75 (95% confidence interval [CI]=42.53-168.91; p=8.96×10[-15]) with sensitivity and negative predictive values of 92% and 98%, respectively. The higher prevalence of HLA-B 1502 allele among certain Asian populations (10-15%) compared to Caucasians (1-2%) may explain a 10-fold to 25-fold higher incidence of CBZ-SJS/TEN in patients from Asia. Screening for HLA-B 1502 before using CBZ can prevent SJS/TEN in certain populations, but screening may be less beneficial in populations with low HLA-B 1502 allele frequency and in patients exposed to CBZ for more than 2 months. A retrospective study demonstrated that the costs of HLA-B 1502 screening were less than those of SJS treatment. This article reviews possible benefits and concerns of HLA-B 1502 screening in clinical practice.