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.

Movement disorders associated with antiseizure medications: A systematic review

New-onset movement disorders have been frequently reported in association with the use of antiseizure medications (ASMs). The frequency of specific motor manifestations and the spectrum of their semiology for various ASMs have not been well characterized. We carried out a systematic review of literature and conducted a search on CINAHL, Cochrane Library, EMBASE, MEDLINE, PsycINFO, and Scopus from inception to April 2021. We compiled the data for all currently available ASMs using the conventional terminology of movement disorders. Among 5123 manuscripts identified by the search, 437 met the inclusion criteria. The largest number of reports of abnormal movements were in association with phenobarbital, valproic acid, lacosamide, and perampanel, and predominantly included tremor and ataxia. The majority of attempted interventions for all agents were discontinuation of the offending drug or dose reduction which led to the resolution of symptoms in most patients. Familiarity with the movement disorder phenomenology previously encountered in relation with specific ASMs facilitates early recognition of adverse effects and timely institution of targeted interventions.

Antiepileptic drug discontinuation by people with epilepsy in the general population

OBJECTIVE

Rate, reasons, and predictors of antiepileptic drug (AED) discontinuation were investigated in a well-defined cohort of people with epilepsy to verify efficacy and tolerability of treatment up to 20 years from treatment initiation.

METHODS

The history of AED usage in children and adults with epilepsy registered with 123 family physicians in an area of Northern Italy between 2000 and 2008 was recorded. Cumulative probabilities of AED withdrawal for specific reasons were estimated using cumulative incidence functions. The probabilities of withdrawing for terminal remission, and of achieving sustained remission while still on treatment, were also evaluated. The roles of sex, age at diagnosis, seizure types, duration at diagnosis, and syndrome were assessed with hazard ratios and 95% confidence intervals.

RESULTS

Seven hundred thirty-one of 747 individuals were treated with one or more AEDs during the disease course. The three commonest drugs were valproate, carbamazepine, and phenobarbital. Reported reasons for AED withdrawal were, in decreasing order, terminal remission, ineffectiveness, and adverse events. The probability of withdrawing the first AED for terminal remission was 1.0% at 1 year and increased to 20.0% at 20 years. Corresponding rates were 2.9% and 12.6% for ineffectiveness and 0.5% and 3.3% for adverse events. Reasons for withdrawal varied with individuals' age, sex, disease characteristics, and drugs.

SIGNIFICANCE

The initial AED given was retained in the majority of cases. Terminal remission, lack of efficacy, and adverse effects were, in decreasing order, the commonest reasons for AED discontinuation. Withdrawal could be predicted by age at diagnosis, sex, and clinical characteristics and varies among drugs.

Long-term safety and sustained efficacy of USL255 (topiramate extended-release capsules) in patients with refractory partial-onset seizures

OBJECTIVE

The aim of this study was to evaluate long-term safety, efficacy, and quality of life (QOL) of ≤400-mg/day USL255, Qudexy® XR (topiramate) extended-release capsules, as adjunctive therapy for partial-onset seizures (POS) in adults.

METHODS

Patients who completed the 11-week double-blind treatment phase of the phase 3 PREVAIL study were eligible to enroll in this 1-year open-label extension (OLE) study (PREVAIL OLE). The primary objective was to evaluate the safety and tolerability of USL255 (including treatment-emergent adverse events [TEAEs]). The secondary objective was to assess seizure frequency in patients (e.g., median percent reduction from baseline in weekly POS frequency, responder rate [proportion of patients with ≥25%, ≥50%, ≥75%, or 100% reduction from baseline in POS frequency], and seizure-free intervals [proportion of patients who were seizure-free for 4, 12, 24, 36, or 48weeks]). Exploratory clinical-status endpoints included the Global Impression of Change (CGI-C) and Quality of Life in Epilepsy-Problems (QOLIE-31-P) questionnaires. Post hoc analyses evaluated neurocognitive TEAE incidences during the first 11 and entire 55weeks of treatment and efficacy by patient age and drug-resistant status.

RESULTS

Of the 217 patients who completed PREVAIL (USL255, n=103; placebo, n=114), 210 (97%) enrolled in PREVAIL OLE and were included in the ITT population. Across the entire 55-week treatment period, USL255 was generally safe and well tolerated, with low individual neurocognitive TEAE incidences. Seizure reduction was sustained across the year-long study and observed in patient subgroups, including those with highly drug-resistant seizures and those ≥50years of age. Improvements in CGI-C and QOLIE-31-P were also observed.

SIGNIFICANCE

The results of PREVAIL OLE are consistent with those from PREVAIL and demonstrate that adjunctive treatment with up to 400mg/day of USL255 may be a safe and effective treatment option for a variety of adult patients with refractory POS.