Single centre 20 year survey of antiepileptic drug-induced hypersensitivity reactions

Hypersensitivity Reactions to Anticonvulsants

BACKGROUND

Antiepileptics are the mainstay of treatment for seizure management. Immediate and delayed hypersensitivity reactions associated with antiepileptics are common. It is important to differentiate between these reactions as management and prognosis varies.

OBJECTIVE

This review article aims to describe the types of hypersensitivity reactions reported with antiepileptics with emphasis on delayed hypersensitivity reactions, as these can be life-threatening.

METHODS

Online databases including PubMed and Cochrane were searched, from the inception of the literature to 5/10/24. Studies focusing on hypersensitivity reactions to antiepileptics were reviewed. Case reports, case series, observational studies, and clinical trials were included. Abstracts and studies published in languages other than English were not included.

RESULTS

Immediate reactions can occur with antiepileptics however the incidence is lower than that of delayed hypersensitivity reactions. Delayed hypersensitivity reactions include benign rash as well as severe cutaneous adverse reactions. Acute generalized exanthematous pustulosis, drug rash with eosinophilia and systemic symptoms, Steven Johnson syndrome, and toxic epidermal necrolysis are discussed in detail in this review. We focused on pathogenesis, genetic predisposition, clinical presentation, treatment, and prognosis.

CONCLUSION

Severe cutaneous adverse reactions can be lethal. It is important to make the correct diagnosis and treat patients accordingly. More studies comparing therapeutic options head-to-head are needed.

Sex Differences in Adverse Effects of Antiseizure Medications in Adults with Epilepsy: A Systematic Review

BACKGROUND

Sex differences in epilepsy have been described in prevalence, seizure propensity and response to treatment. Therefore, taking into account sex-based differences in epilepsy is important for both diagnostic purposes and therapeutic considerations. However, little is known about sex differences in adverse effects of antiseizure medications (ASMs).

OBJECTIVES

We performed a systematic review searching for sex differences in adverse effects of ASMs in adult persons with epilepsy (PWE) as part of a wider project aimed to assess sex-based differences in efficacy and adverse effects of ASMs in PWE.

METHODS

We conducted a comprehensive literature search in the PubMed database. The search was conducted with no restriction on publication date, and all results up to April 2020 were included. We included articles written in English, Italian, Spanish, or French that evaluated adverse effects of one or more ASMs in PWE, with specific mention of the two sexes. When appropriate, Newcastle-Ottawa or Jadad scales were used to assess study quality.

RESULTS

Of 5164 identified studies, only 167 considered sex in the analysis and were therefore included. Significant sex-related differences were found in 58 of those studies. We found a consistently higher frequency of cutaneous adverse effects in females; higher risk of developing general adverse effects on different ASMs in females; stronger risk of adverse effects on bone metabolism in females, mainly on treatment with enzyme-inducing ASMs; a concordant higher risk of visual field loss was noted in males on vigabatrin; an overall worse lipid profile in males; as well as higher leptin levels and higher body mass index in females treated with various ASMs.

CONCLUSIONS

Our analysis has identified some important sex differences in the adverse effects of ASMs. Clinicians should be aware of these differences when informing patients about the risks associated with ASM treatment in PWE.

Efficacy and tolerability of immediate switch from sodium channel blockers to Lacosamide

Lacosamide (LCM) is a new-generation anti-seizure medication approved for monotherapy and add-on therapy for focal-onset epilepsy. It has novel pharmacodynamics and favorable pharmacokinetic qualities with good clinical response. This study aims to evaluate the effectiveness and tolerability of LCM when used in the immediate switch from sodium channel blockers in patients with focal-onset and generalized-onset epilepsies. This retrospective, multicenter observational study was conducted with adult patients who received LCM as mono- or polytherapy through immediate switch with 6 to 52 months follow-up. The clinical data obtained during the follow-up period were analyzed to assess retention rate, seizure freedom, more than 50% seizure reduction, and adverse effects. A total of 32 patients (eight females, 24 males) with a median age of 49.75 (range, 23-86) years, median age at epilepsy onset of 32.58 (range, 0.5-85) years, and median epilepsy duration of 17.17 (range, 1-46) years were included in this study. Seizure frequency was between 1 and 90 in the past 6 months. Seven (21.9%) of the patients had structural brain lesions and 27 (84.4%) of the patients had EEG abnormalities. The adverse effects leading to switching were hyponatremia, rash, elevated liver enzymes, pain, and erectile dysfunction. At 14.34 (range, 6-52) months follow-up, 30 (93.75%) patients in total retained LCM, 20 (66.7%) of them were seizure-free, and 13 were on LCM monotherapy. Responder rate was 81.25%. Eight (25%) of the patients experienced adverse effects after the immediate switch. One patient with generalized-onset epilepsy needed to quit LCM due to an increase in seizures. Seizure frequency did not change in three patients in the focal-onset group. Immediate switch to LCM showed favorable outcomes with a significant reduction in seizure frequency, high retention rates, and tolerable adverse effect profiles in both focal-onset and generalized-onset seizures.

Antiepileptic Drug Adverse Cutaneous Reaction in Childhood

Antiepileptic drug (AED) side effects can result in treatment failure, morbidity, and mortality. Adverse cutaneous drug reactions (ACRs) frequently occur within the first 2 to 3 months of drug use. We wanted to discuss antiepileptic ACRs in childhood in this study. This was a study of 37 pediatric patients who were diagnosed with ACR and treated with AED in the last 5 years. Over a 5-year period, 37 (1.8%) of the 2,064 epilepsy patients had ACRs. There were 23 (62%) male patients and 14 (38%) female patients. Patients had a median age of 6 years (interquartile range: [IQR]: 3.5–10). The ACRs occurred in a median of 20 (IQR: 14–30) days. There were 28 (75%) patients receiving monotherapy and 9 (25%) patients receiving polytherapy. Overall, 22 (59.5%) of the 37 patients used aromatic drugs (AD), while 15 (40.5%) used nonaromatic drugs (NAD). Morbilliform eruptions accounted for the majority of ACRs (84%). Valproic acid (54%) was the most frequently used AED that resulted in ACRs. There was no significant difference in terms of eruption time, gender, or age between AD and NAD. Within 1 to 2 months of initiating a new AED, patients should be closely monitored for ACRs. If an ACR develops for one AED, greater caution should be taken when initiating the other AED. Although it is well established that ADs cause more skin reactions, we found that one of the NADs, valproic acid, causes more skin reactions.

Association of HLA-B*51:01, HLA-B*55:01, CYP2C9*3, and Phenytoin-Induced Cutaneous Adverse Drug Reactions in the South Indian Tamil Population

Phenytoin (PHT) is one of the most commonly reported aromatic anti-epileptic drugs (AEDs) to cause cutaneous adverse reactions (CADRs), particularly severe cutaneous adverse reactions (SCARs). Although human leukocyte antigen (HLA)-B*15:02 is associated with PHT-induced Steven Johnson syndrome/toxic epidermal necrosis (SJS/TEN) in East Asians, the association is much weaker than it is reported for carbamazepine (CBZ). In this study, we investigated the association of pharmacogenetic variants of the HLA B gene and CYP2C9*3 with PHT-CADRs in South Indian epileptic patients. This prospective case-controlled study included 25 PHT-induced CADRs, 30 phenytoin-tolerant patients, and 463 (HLA-B) and 82 (CYP2C9*3) normal-controls from previous studies included for the case and normal-control comparison. Six SCARs cases and 19 mild-moderate reactions were observed among the 25 cases. Pooled data analysis was performed for the HLA B*51:01 and PHT-CADRs associations. The Fisher exact test and multivariate binary logistic regression analysis were used to identify the susceptible alleles associated with PHT-CADRs. Multivariate analysis showed that CYP2C9*3 was significantly associated with overall PHT-CADRs (OR = 12.00, 95% CI 2.759–84.87, p = 003). In subgroup analysis, CYP2C9*3 and HLA B*55:01 were found to be associated with PHT-SCARs (OR = 12.45, 95% CI 1.138–136.2, p = 0.003) and PHT-maculopapular exanthema (MPE) (OR = 4.041, 95% CI 1.125–15.67, p = 0.035), respectively. Pooled data analysis has confirmed the association between HLA B*51:01/PHT-SCARs (OR = 6.273, 95% CI 2.24–16.69, p = <0.001) and HLA B*51:01/PHT-overall CADRs (OR = 2.323, 95% CI 1.22–5.899, p = 0.037). In this study, neither the case nor the control groups had any patients with HLA B*15:02. The risk variables for PHT-SCARs, PHT-overall CADRs, and PHT-MPE were found to be HLA B*51:01, CYP2C9*3, and HLA B*55:01, respectively. These alleles were identified as the risk factors for the first time in the South Indian Tamil population for PHT-CADRs. Further investigation is warranted to establish the clinical relevance of these alleles in this population with larger sample size.

Sex Differences in the Risk of Cutaneous Adverse Drug Reactions Induced by Antiseizure Medications: A Systematic Review and Meta-analysis

BACKGROUND

Cutaneous adverse drug reactions (cADRs) are one of the most common, severe, and life-threatening types of adverse reactions following treatment with antiseizure medications (ASMs). Some studies have reported a higher incidence of ASM-induced cADRs in females than in males.

OBJECTIVE

This study sought to perform a systematic review, meta-analysis, and meta-regression to compare the ASM cADR risks between females and males.

METHODS

We searched the literature using three databases (EMBASE, PubMed, and Web of Science) between October 1998 and November 2018, later updated to October 2019. Studies were included in the meta-analysis if they met the following criteria: (1) observational studies that estimated the incidence of cADRs related to ASMs; (2) provided the risk or odds ratio (OR) for cADRs among female and male patients exposed to ASMs; and (3) provided information on patients' characteristics. We assessed the impact of study characteristics, publication bias, and measures to reduce bias, and performed a DerSimonian and Laird random effects meta-analysis.

RESULTS

We included 28 studies in this review. Of these, seven studies were eligible for inclusion in the meta-analysis, involving a total of 223,209 patients. Overall, females were more likely to develop cADRs to ASMs than males (OR 1.76, 95% confidence interval [CI] 1.55-1.99). The largest differences were observed in patients prescribed lamotrigine (OR 2.17, 95% CI 1.53-3.08, p < 0.001) and carbamazepine (OR 1.63, 95% CI 1.02-2.60, p = 0.042). Also, the OR trended higher for phenytoin (OR 2.46, 95% CI 0.79-7.65, p = 0.12), followed by oxcarbazepine (OR 1.91, 95% CI 0.75-4.85, p = 0.18) and sodium valproate (OR 0.60, 95% CI 0.12-2.99, p = 0.53), but the difference did not reach statistical significance. In the remaining 21 studies, 13 reported numerically higher risk of cADRs among females compared to male patients, and in five of these, the difference was statistically significant.

CONCLUSION

Our findings confirmed that females are more susceptible to cADRs induced by ASMs than males. More research is needed to understand the pathophysiological mechanisms for this difference.

PROTOCOL REGISTRATION

PROSPERO (CRD42018111943).

Rashes and other hypersensitivity reactions associated with antiepileptic drugs: A review of current literature

This article provides an overview of the pathogenesis and risk factors associated with antiepileptic drug (AED) hypersensitivity reactions, provides prescribing guidelines that may minimize the risk of antiepileptic induced rashes, and discusses treatment options for rashes. Articles indexed in PubMed, Science Citation, and Google Scholar (January 1946-March 2019) were systematic searched using the following key terms: hypersensitivity, rash, antiepileptic, epilepsy, cross-sensitivity, desensitization, patch testing and supplemented with our clinical experiences. Additional references were identified from a review of literature citations. AEDs are associated with cutaneous adverse reactions. Aromatic AEDs and higher titration rates are associated with increased risk of hypersensitivity reaction. Patient characteristics, underlying health conditions, and genetic variations may increase the likelihood of a hypersensitivity reaction. Once a hypersensitivity reaction occurs, the likelihood of cross sensitivity to another AED increases, especially among other aromatic AEDs. Withdrawal of the causal agent and initiation of a lower risk agent usually leads to resolution of symptoms. Desensitization protocols may be an option for patients whose seizures only respond to the AED causing the rash.

Making Rash Decisions in Epilepsy: Evaluating Hypersensitivity Reactions to Anti-seizure Medications