A prospective audit of adjunctive zonisamide in an everyday clinical setting

Zonisamide oral suspension as adjunctive therapy for treating partial seizures in adults and in pediatric patients aged 16 years and older with epilepsy

INTRODUCTION

Zonisamide (ZNS), is an antiseizure medication (ASM) approved by the US FDA and the European Medicines Agency (EMA) for focal-onset seizures. An oral suspension formulation has recently been introduced to improve administration for specific patient populations, particularly those with swallowing difficulties.

AREAS COVERED

This article explores the new ZNS oral suspension, evaluating its pharmacokinetic benefits, impact on patient care, and adherence. Bioavailability studies confirm that the oral suspension is bioequivalent to ZNS capsules, though no additional clinical trials in epilepsy patients have been conducted. This review presents and discusses the oral suspension's benefits, such as ease of administration for those with swallowing difficulties and flexible dosing, while also addressing potential drawbacks, including dosing accuracy and stability issues.

EXPERT OPINION

The ZNS oral suspension allows additional flexibility for epilepsy management, particularly for patients unable to swallow capsules. Its bioavailability and specific formulation may improve adherence and seizure control.

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.

Adjunctive brivaracetam - A prospective audit of outcomes from an epilepsy clinic

OBJECTIVE

Brivaracetam (BRV), is licensed in Europe as adjunctive treatment, and in the United States of America as adjunctive and monotherapy for focal seizures with or without secondary generalization in adults, adolescents, and children ≥4 years. As BRV becomes available globally, this prospective audit was undertaken to gain an understanding of how best to use the anti-seizure medication (ASM) in the everyday clinical setting.

METHODS

Brivaracetam was started by patients ≥16 years with difficult-to-control epilepsy at Glasgow epilepsy clinics following a 12-week baseline on stable ASM doses. Target dosing was 200 mg/day. Review occurred every 12-16 weeks until 1 of 4 end-points occurred: seizure freedom for ≥6 months on a given BRV dose; ≥50% (responder) or <50% (marginal benefit) seizure reduction over 6 months compared with baseline on the highest tolerated BRV dose; withdrawal of BRV due to lack of efficacy, adverse effects, or both.

RESULTS

An end-point has been reached by 108 patients (38 men, 70 women; median age 45 years), 88 with focal-onset seizures and 20 with genetic generalized epilepsies (GGEs). Of these, 71 (65.7%) have benefitted from BRV, including 23 (21.3%) who have been seizure free for ≥6 months on a median BRV dose of 100 mg/day (range 25-200 mg/day). A further 18 (16.7%) were classified as responders and 30 (27.8%) showed marginal benefit. Brivaracetam benefitted 16 (80.0%) patients with GGEs, 5 becoming seizure free. Generalized tonic-clonic seizures, absences, and myoclonic seizures were completely controlled in 4 (25%) patients with juvenile myoclonic epilepsy. Brivaracetam monotherapy was established in 12 patients, 3 of whom had GGEs. Levetiracetam (LEV) had previously been prescribed in 53 patients who had discontinued the ASM due to lack of efficacy, side effects, or both. Adjunctive BRV benefitted 34 (64.2%) of these patients. Brivaracetam was withdrawn in 37 (34.3%) patients, (23 side effects, 4 lack of efficacy, 10 both). Sedation was the commonest side effect leading to BRV withdrawal (n = 14; 13.0%). Psychiatric side effects resulted in BRV discontinuation in 9 (8.3%) patients.

SIGNIFICANCE

Brivaracetam has efficacy for a range of seizure types and syndromes in a wide range of doses. The ASM can produce positive outcomes in patients who have failed LEV. Post-marketing studies remain a useful tool to evaluate the efficacy and tolerability of novel ASMs in everyday clinical practice.

Pharmacological Management of the Genetic Generalised Epilepsies in Adolescents and Adults

Common genetic generalised epilepsy syndromes encountered by clinicians include childhood and juvenile absence epilepsies, juvenile myoclonic epilepsy and generalised tonic-clonic seizures on awakening. Treatment of these syndromes involves largely the use of broad-spectrum antiseizure drugs. Those effective for the generalised epilepsies include sodium valproate, phenobarbital, ethosuximide, clobazam, clonazepam, lamotrigine, levetiracetam, topiramate, zonisamide and, more recently, perampanel and brivaracetam. Results from the few rigorous studies comparing outcomes with drugs for genetic generalised epilepsies show valproate to be the most effective. The majority of patients with genetic generalised epilepsy syndromes will become seizure free on antiseizure monotherapy; those for whom control proves elusive may benefit from combination regimens. Early counselling regarding management may assist the patient to come to terms with their diagnosis and improve long-term outcomes. Treatment can be lifelong in some individuals, although others may remain seizure free without medication. Choice of antiseizure medication depends on the efficacy for specific seizure types, as well as tolerability. For patients prescribed comedication, drug interactions should be considered. In particular, for young women taking oral hormonal contraceptives, ≥ 200 mg/day of topiramate can decrease the circulating concentration of ethinylestradiol and ≥ 12 mg/day of perampanel can induce levonorgestrel metabolism. The use of valproate in women of childbearing potential is limited by associated teratogenic and neurodevelopmental effects in offspring. Given that valproate is often the antiseizure drug of choice for genetic generalised epilepsies, this creates a dilemma for patients and clinicians. Decision making can be aided by comprehensive assessment and discussion of treatment options. Psychiatric comorbidities are common in adolescents and adults with genetic generalised epilepsies. These worsen the prognosis, both in terms of seizure control and quality of life. Attendant lifestyle issues can impact significantly on the individual and society. Frontal lobe dysfunction, which can present in patients with juvenile myoclonic epilepsy, can adversely affect the long-term outlook, regardless of the nature of seizure control. Ongoing management requires consideration of psychosocial and behavioural factors that can complicate diagnosis and treatment. An assured supportive attitude by the neurologist can be an important contributor to a positive outcome. The mechanisms underlying genetic generalised epilepsies, including genetic abnormalities, are unclear at present. As the pathophysiology is unravelled, this may lead to the development of novel therapies and improved outcomes for patients with these syndromes.

Perspective: Therapeutic Potential of Flavonoids as Alternative Medicines in Epilepsy

Epilepsy is a chronic neurological disorder that affects many people worldwide. Temporal lobe epilepsy is the most common and most studied type of epilepsy, but the pathological mechanisms underlying this condition are poorly understood. More than 20 antiepileptic drugs (AEDs) have been developed and used for the treatment of epilepsy; however, 30% of patients still experience uncontrolled epilepsy and associated comorbidities, which impair their quality of life. In addition, various side effects have been reported for AEDs, such as drowsiness, unsteadiness, dizziness, blurred or double vision, tremor (shakiness), greater risk of infections, bruising, and bleeding. Thus, critical medical needs remain unmet for patients with uncontrolled epilepsy. Flavonoids belong to a subclass of polyphenols that are widely present in fruits, vegetables, and certain beverages. Recently, many studies have reported that some flavonoids elicit various beneficial effects in patients with epilepsy without causing the side effects associated with conventional medical therapies. Moreover, flavonoids may have a property of regulating microRNA expression associated with inflammation and cell survival. These findings suggest that flavonoids, which are more effective but impose fewer adverse effects than conventional AEDs, could be used in the treatment of epilepsy.

Efficacy, tolerability, and retention rates of zonisamide in older adult patients with focal-onset epilepsy: Experiences from two tertiary epilepsy centers

OBJECTIVE

The objective of this study was to evaluate the efficacy, tolerability, and retention rates for zonisamide (ZNS) in older adult patients with focal-onset epilepsy.

PATIENTS AND METHODS

Chart reviews of patients aged 60years and older with focal-onset epilepsy treated with ZNS in two tertiary epilepsy centers were analyzed retrospectively.

RESULTS

Eighty-five patients (41 males, 44 females) aged over 60years (range: 60-81) with focal-onset epilepsy treated with ZNS were identified; 55.3% of the patients (n=47) were on monotherapy. The median and average doses of ZNS doses were 200mg/day (range: 100-400) and 212.9±84.2mg/day, respectively. With ZNS treatment, 67.1% of the patients (n=57) were seizure-free for a median of 28months (range: 10-56) whereas 20% (n=17) of the patients had seizures that were unresponsive to ZNS treatment. Best seizure control was achieved in patients with poststroke epilepsy; seizure freedom was 80% in this subgroup. Overall retention rate was found to be 83.5%. There was no significant relation between receiving poly- or monotherapy and discontinuation of ZNS (p=0.18). Thirty-two of the patients (37.6%) lost weight. Median weight loss was 8kg (range: 2-16). There was no significant correlation between weight loss and the administered doses of ZNS (r=0.34; p=0.12).

CONCLUSION

Despite limitations due to the retrospective design of the study, the results show that ZNS is a well-retained drug with high efficacy in older adult patients with epilepsy.

Psychiatric side effects and antiepileptic drugs: Observations from prospective audits

Psychiatric comorbidities are common in people with epilepsy. A retrospective study of characteristics associated with withdrawal due to psychiatric side effects was undertaken in patients with treated epilepsy participating in prospective audits with new antiepileptic drugs (AEDs). A total of 1058 treated patients with uncontrolled seizures (942 focal-onset seizures, 116 generalized genetic epilepsies [GGEs]) participated in eight prospective, observational audits from 1996 to 2014. These patients were prescribed adjunctive topiramate (n=170), levetiracetam (n=220), pregabalin (n=135), zonisamide (n=203), lacosamide (n=160), eslicarbazepine acetate (n=52), retigabine (n=64), or perampanel (n=54). Doses were titrated according to efficacy and tolerability to optimize zeizure outcomes and reduce side effects. Psychiatric comorbidities were recorded prior to and after the addition of each AED. At baseline, patients with focal-onset seizures (189 of 942; 20.1%) were statistically more likely to have psychiatric diagnoses compared to patients with GGEs (14 of 116, 12.1%; p=0.039). Following adjunctive AED treatment, neuropsychiatric adverse effects led to AED withdrawal in 1.9-16.7% of patients. Patients with a pre-treatment psychiatric history (22 of 209; 10.5%) were statistically more likely to discontinue their new AED due to psychiatric issues compared to patients with no previous psychiatric diagnosis (50 of 849; 5.9%; p=0.017). Patients receiving sodium channel blocking AEDs (4 of 212, 1.9%) were statistically less likely to develop intolerable psychiatric problems, compared to those on AEDs possessing other mechanisms of action (68 of 846, 8.0%; p=0.012). Depression was the commonest problem, leading to discontinuation of AEDs in 2.8% (n=30) patients. Aggression was statistically more common in men (11 of 527, 2.1%) compared to women (1 of 531, 0.2%; p=0.004). Patients with learning disability (12 of 122, 9.8%; p=0.0015) were statistically less likely to have psychiatric issues prior to adjunctive AED treatment compared to other patients (208 of 936, 22.2%), but there were no statistically significant differences once the new AEDs were added (8 of 122 patients with learning disability, 6.6%; 64 of 936 other patients, 6.8%). Awareness of these issues may assist clinicians in avoiding, identifying and treating psychiatric comorbidities in people with epilepsy.

Tolerability and Safety of Commonly Used Antiepileptic Drugs in Adolescents and Adults: A Clinician's Overview

This paper discusses the issues surrounding the tolerability and safety of the commonly used antiepileptic drugs (AEDs) in adolescents and adults. The content includes dose-related adverse effects, idiosyncratic reactions, behavioural and psychiatric comorbidities, chronic problems, enzyme induction and teratogenesis. Twenty-one AEDs are discussed in chronological order of their introduction into the UK, starting with phenobarbital and ending with brivaracetam. Wherever possible, advice is given on anticipating, recognising and managing these issues and thereby improving the lives of people with epilepsy, most of whom will need to take one or more of these agents for life. Avoidance of side effects will increase the possibility of achieving and maintaining long-term seizure freedom. Alternatively, adverse events from AEDs will substantially reduce quality of life and often result in higher healthcare costs.

Prospective audit with adjunctive perampanel: Preliminary observations in focal epilepsy

PURPOSE

Perampanel (PER) was first licensed in the United Kingdom in 2012 for the adjunctive treatment of focal seizures with or without secondary generalization in adults and children over 12years of age. It has recently also been approved for use as add-on therapy for patients with primary generalized tonic-clonic seizures. This prospective audit reports preliminary outcomes with adjunctive PER in patients with focal-onset seizures in everyday clinical practice using a standard design.

METHODS

To date, 54 patients (38 males, 16 females; 21-65years, median: 48years) have completed the study. The median monthly seizure frequency was 4 (range: 1-60). At baseline, patients were taking a median of 2 other antiepileptic drugs (range: 1-4 drugs), with their seizures having previously failed to improve on a median of 3 schedules (range: 1-15 schedules). After 12weeks of stable dosing, PER was added, aiming at a target range of 6-12mg/daily. Review took place every 6-8weeks until one of 4 endpoints was reached: seizure freedom for ≥6months on a given PER dose, ≥50% (responder) or <50% (marginal effect) seizure reduction over 6months, compared with the prospective baseline, on the highest tolerated PER dose, or withdrawal of PER due to a lack of efficacy or side effects.

RESULTS

Three (5.6%) patients have remained seizure-free, with 8 (14.8%) demonstrating a ≥50% response and a further 17 (31.5%) reporting a marginal effect. Of the 26 (48.1%) dropping out of PER treatment, 21 (38.9%) did so because of side effects. The commonest problems were nausea, vomiting, ataxia, dizziness, and sedation. Overall, 6 (11%) patients developed neuropsychiatric problems, with 3 reporting irritability and/or aggression. Two patients had substantial weight gain, and another patient suffered recurrent falls. Treatment with enzyme-inducing AEDs had no effect on PER dosing in patients responding to PER or withdrawing due to side effects.

SIGNIFICANCE

These data support the value of adjunctive PER in some patients with pharmacoresistant epilepsy in everyday clinical practice.

Third International Congress on Epilepsy, Brain, and Mind: Part 2

Epilepsy is both a disease of the brain and the mind. Here, we present the second of two papers with extended summaries of selected presentations of the Third International Congress on Epilepsy, Brain and Mind (April 3-5, 2014; Brno, Czech Republic). Humanistic, biologic, and therapeutic aspects of epilepsy, particularly those related to the mind, were discussed. The extended summaries provide current overviews of epilepsy, cognitive impairment, and treatment, including brain functional connectivity and functional organization; juvenile myoclonic epilepsy; cognitive problems in newly diagnosed epilepsy; SUDEP including studies on prevention and involvement of the serotoninergic system; aggression and antiepileptic drugs; body, mind, and brain, including pain, orientation, the "self-location", Gourmand syndrome, and obesity; euphoria, obsessions, and compulsions; and circumstantiality and psychiatric comorbidities.

Retention rate of zonisamide in intractable epilepsy

OBJECTIVES

To assess the effect and tolerability of zonisamide (ZNS) as adjunctive treatment for difficult-to-treat epilepsy in adult Scandinavian patients.

MATERIAL AND METHODS

151 outpatients (mean age: 42.5 years) from 18 centres in Denmark, Sweden and Norway were recruited to the study. 81.5% had focal epilepsy, and the mean number of previously tried AEDs was 4.5. The patients were given ZNS as add-on treatment, and the ZNS dosing and the visit frequency were governed by the treating physician. The primary efficacy endpoint was the retention rate after 12-month treatment. Assessments included also responder rate, type and frequency of adverse events, healthcare resource utilization (HCRU) and quality of life (QOLIE-31).

RESULTS

90 patients (59.6%) completed the study. Mean daily ZNS dose was 300.8 mg. After 12 months, 81 patients were still on ZNS, that is a retention rate of 53.6%. The mean reduction of seizure frequency at 12 months was 27%. Best effect was seen in those with focal and those with secondary generalized seizures. In the QOLIE-31, there was a mean increase from baseline of 4.8 points. The tolerability was generally good. The majority of side effects were CNS-related, dizziness, fatigue, seizure aggravation, and headache being most prevalent. 21.2% had adverse events leading to withdrawal of ZNS.

CONCLUSIONS

A retention rate of 53.6% after 1 year of treatment with ZNS is roughly in accordance with the retention rates found for lamotrigine, oxcarbazepine, levetiracetam and topiramate in drug-resistant patients.

Early add-on lacosamide in a real-life setting: results of the REALLY study

BACKGROUND AND OBJECTIVES

Many patients with epilepsy are treated with antiepileptic drug (AED) polytherapy. Several factors influence the choice of early add-on therapy, and deciding on the most appropriate drug can be difficult. This study aimed to assess the efficacy and tolerability of lacosamide as early add-on therapy in patients with partial-onset seizures.

METHODS

REALLY (REtrospective study of lAcosamide as earLy add-on aLong one Year) was a multicenter, retrospective, 1-year, real-life study. Patients included were aged older than 16 years, had partial-onset seizures, and were treated with lacosamide as add-on therapy after one or two prior AEDs. Data were collected retrospectively from clinical records. The primary study objective was to assess the efficacy of lacosamide over 12 months (seizure-free and responder rates), and the secondary objective was to assess the tolerability of lacosamide at 3, 6, and 12 months [adverse events (AEs) and discontinuation].

RESULTS

One hundred and ninety-nine patients were enrolled in the study; 89 patients (44.7 %) had tried one AED and 110 patients (55.3 %) had tried two AEDs before lacosamide. At 12 months, the proportion of patients who were seizure free was 44.9 %, and 76 % of patients were responders. The seizure-free rate at 12 months for patients who had previously received one or two AEDs was 58 and 34.3 %, and the responder rate at 12 months was 83.0 and 70.4 %, respectively. The AE rate was 21.5 % at 3 months, 27.1 % at 6 months, and 31.2 % at 12 months, with 7.0 % of patients discontinuing treatment because of an AE. The most common AE reported was dizziness (11.6 %). Cryptogenic epilepsy, a higher number of prior AEDs, and the use of a sodium channel blocker at onset were associated with a worse outcome. The number of concomitant AEDs decreased over 1 year (Z = 5.89; p < 0.001). Twenty-two patients were converted to lacosamide monotherapy with at least one evaluation ≥6 months from the beginning of monotherapy conversion.

CONCLUSIONS

Lacosamide was effective and well tolerated as early add-on treatment in patients who had received one or two previous AEDs.

Long-term safety and efficacy of eslicarbazepine acetate in patients with focal seizures: results of the 1-year ESLIBASE retrospective study

BACKGROUND

Eslicarbazepine acetate (ESL) is a new antiepileptic drug (AED) licensed as adjunctive therapy in adults with partial-onset or focal seizures.

OBJECTIVE

To evaluate in a clinical practice setting the long-term efficacy and safety of ESL in patients with focal seizures.

METHODS

ESLIBASE was a retrospective study that included all patients with focal seizures who started ESL between January 2010 and July 2012 at 12 hospitals. ESL was prescribed individually according to real-life practice. Efficacy and safety were evaluated over 1 year. Switching from carbamazepine (CBZ) and oxcarbazepine (OXC) was assessed.

RESULTS

Three hundred and twenty-seven patients were included; 78% of patients were taking ≥2 other AEDs at baseline. Most (87%) began ESL because of poor seizure control and 13% because of adverse events (AEs) with CBZ or OXC. After 1 year, 237 patients (72.4%) remained on ESL. At 3, 6 and 12 months, the responder rate was 46.3%, 57.9%, and 52.5%, and 21.0%, 28.0%, and 25.3% of patients were seizure free. The responder rate significantly increased when ESL was combined with a non-sodium channel-targeting drug (non-SC drug) (66.7%) versus an SC drug (47.7%; p<0.001). At 12 months, 40.7% of patients had ≥1 AE; AEs led to treatment discontinuation in 16.2%. Dizziness, nausea, and somnolence were the most common AEs. The tolerability profile improved in >50% of the patients who switched from CBZ or OXC to ESL because of AEs.

CONCLUSIONS

ESL was well tolerated and effective in a real-world setting over 1 year. Side-effect profile improved when OXC and CBZ recipients were switched to ESL.

Pharmacotherapy for tonic-clonic seizures

INTRODUCTION

Occurrence of generalized tonic-clonic seizures (GTCS) is one of the most important risk factors of seizure-related complications and comorbidities in patients with epilepsy. Their prevention is therefore an important aspect of therapeutic management both in idiopathic generalized epilepsies and in focal epilepsies.

AREAS COVERED

It has been shown that the efficacy of antiepileptic drugs (AEDs) varies across epilepsy syndromes, with some AEDs efficacious against focal seizures with secondary GTCS (sGTCS) but aggravating primary GTCS (pGTCS). In patients with pGTCS, evidence-based data support the preferential use of valproic acid, lamotrigine, levetiracetam and topiramate. In patients with sGTCS, all AEDs approved in the treatment of focal epilepsies might be used.

EXPERT OPINION

Both in pGTCS and sGTCS, additional data are required, specifically to inform about the relative efficacy of AEDs in relation to each other. Although valproic acid might be the most efficacious drug in idiopathic generalized epilepsies, it should be avoided in women of childbearing age due to its safety profile. In patients with sGTCS, AEDs for which the impact on this seizure type has been formally evaluated and which have demonstrated greater efficacy than placebo might preferentially be used, such as lacosamide, perampanel and topiramate.

Involuntary weight loss

Involuntary weight loss remains an important and challenging clinical problem, with a high degree of morbidity and mortality. Because of the frequency of finding a serious underlying diagnosis, clinicians must be thorough in assessment, keeping in mind a broad range of possible causes. Although prediction scores exist, they have not been broadly validated; therefore, clinical judgment remains ever essential.

Prospective audits with newer antiepileptic drugs in focal epilepsy: insights into population responses?

Despite the availability of a wide range of new antiepileptic drugs (AEDs), there is little evidence that their introduction has substantially altered outcomes. This paper reviews data from 5 consecutive prospective audits with new AEDs using similar methodology. Prospective audits with topiramate (TPM; n=135), levetiracetam (LEV; n=136), zonisamide (ZNS; n=141), pregabalin (PGB; n=135), and lacosamide (LCM; n=160) were undertaken in treated patients with uncontrolled partial-onset seizures. Follow-up continued until one of four endpoints was reached: seizure freedom for ≥6months on unchanged dosing; ≥50% reduction (responder) in seizure frequency on the highest tolerated dose compared with baseline; <50% seizure frequency reduction (marginal response) compared with baseline in patients wishing to continue treatment with the new AED; or withdrawal due to lack of efficacy, side effects, or both. A greater proportion of seizure-free patients occurred with LEV (23.5%), LCM (21.9%), and TPM (20.7%) than with ZNS (12.8%) and PGB (10.4%). A higher percentage discontinued treatment with ZNS (41.8%) and PGB (50.4%) than with LEV (32.4%), TPM (31.1%), and LCM (22.5%). Most seizure-free patients responded to the new agent as first or second add-on (TPM 96%; LEV 97%; ZNS 89%; PGB 86%; LCM 97%) often at modest or moderate dosing (TPM 68%, ≤200mg/day; LEV 63%, ≤1000mg/day; ZNS 61%, ≤100mg/day; PGB 86%, ≤300mg/day; LCM 74%, ≤200mg/day). With <10% of patients discontinuing all AEDs due to lack of efficacy, tolerability was the major factor influencing the number of patients remaining on treatment. Lacosamide was the best (77% patients continued treatment), while PGB was the worst (50% continued treatment) tolerated AED. Overall, seizure freedom was achieved in <25% of patients in each audit, mainly as a first or second add-on, with best tolerated AEDs producing a higher number of good outcomes. Seizures in very few patients with drug-resistant epilepsy, as defined by the International League Against Epilepsy task force, responded to any of the 5 newer AEDs. These data support the suggestion that the introduction of modern agents has not importantly impacted the outcomes in refractory epilepsy.

Review of therapeutic options for adjuvant treatment of focal seizures in epilepsy: focus on lacosamide

Epilepsy is one of the most common serious neurological conditions worldwide, with an age-adjusted incidence of approximately 50 per 100,000 persons per year in developed countries. Antiepileptic therapy can result in long-term remission in 60-70% of patients, but many patients will require combination treatment to achieve optimal seizure control, as monotherapy is ineffective at controlling seizures in 30-53% of patients. Despite the increase in available treatment options, patient outcomes have not improved significantly and there is still a need for more effective therapies. Drugs used in the treatment of focal-onset seizures are a diverse range of compounds, and in most cases their mechanism of action is unknown or poorly defined. This review discusses the efficacy and safety of the newer adjuvant antiepileptic therapies that may improve outcomes in patients unresponsive to monotherapy, including clobazam, vigabatrin, lamotrigine, gabapentin, topiramate, tiagabine, levetiracetam, oxcarbazepine, pregabalin, zonisamide and eslicarbazepine, with focus on lacosamide. Lacosamide has been shown to exert its anticonvulsant effects predominantly by enhancement of the slow inactivation of voltage-gated sodium channels. Lacosamide is indicated for use as adjuvant treatment of focal-onset seizures in patients with epilepsy, and there is some evidence that it may also be of use in patients with status epilepticus and cancer patients with epilepsy. The efficacy of lacosamide has been assessed in three randomized, double-blind, placebo-controlled clinical trials, all of which have shown lacosamide to be effective at reducing seizure frequency and increasing 50% responder rates in patients with focal-onset seizures. Long-term lacosamide treatment is generally well tolerated and is not associated with significant drug interactions; the availability of an intravenous form of the drug also makes it particularly useful for a broad range of patients.

Adjunctive lacosamide in clinical practice: sodium blockade with a difference?

Lacosamide (LCM) was licensed in the United Kingdom in 2008 for the adjunctive treatment of partial-onset seizures. It exerts its effect by enhancing sodium channel slow inactivation. This article reports preliminary outcomes with adjunctive LCM in the everyday clinical setting. To date, 113 patients (57 males, 56 females; aged range=18-74 years, median=39 years) with uncontrolled partial-onset seizures (monthly frequency range=1-300, median=4) have been included in the audit. Patients were taking 1-4 (median=1) antiepileptic drugs (AEDs), having previously tried 1-12 (median 3) drug schedules. After 12 weeks on stable AED dosing, LCM was added, aiming at an initial target range of 200-400mg/day. Review took place every 6-8 weeks until one of four endpoints was reached: seizure freedom for ≥6 months on a given LCM dose; ≥50% (responder) or <50% (marginal benefit) seizure reduction over 6 months compared with baseline on the highest tolerated LCM dose; withdrawal of LCM because of lack of efficacy, side effects, or both. An endpoint has been reached by 65 (57.5%) patients so far. Seventeen (26.2%) have remained seizure free on a median daily LCM dose of 100mg (range=50-300 mg). Patients were more likely to become seizure free when LCM was used as a first add-on (15/36, 41.7%), compared with a later treatment schedule (1/27, 3.7%, P=0.001). With appropriate dose manipulation, patients taking traditional sodium blockers (5/26, 19.2%) were as likely to become seizure free as those taking AEDs with other mechanisms of action only (11/37, 29.7%). Fifty percent or greater seizure reduction was achieved in an additional 16 (24.6%) patients (1 monotherapy); 18 (27.7%) reported marginal benefit. Two patients were established on LCM monotherapy (one seizure free, one responder). Patients remaining on LCM were as likely to also be taking sodium blockers only (23/27, 85.1%) as AEDs with other mechanisms (26/36, 72.2%). LCM was withdrawn in 14 patients (12.3% of ongoing patients, 21.5% of those at an endpoint; 10 for side effects, 4 for lack of efficacy). The most common side effects leading to withdrawal were sedation, ataxia, and dizziness. Of the 10 with side effects, only 2 patients took concomitant sodium blockers. Patients on sodium valproate were more likely to discontinue LCM (8/21, P=0.018) than those also taking other AEDs; 5 of the 8 did so because of side effects and 3 because of lack of efficacy. In patients with partial-onset seizures, LCM is an effective and well-tolerated adjunctive AED when combined with appropriate doses of traditional sodium blockers, as well as agents with other mechanisms of action. Seizure freedom was more likely when LCM was used as a first add-on compared with a later treatment schedule. Patients also taking sodium valproate were significantly more likely to discontinue LCM compared with those taking other AEDs. These data suggest that the pharmacological effect of LCM differs importantly from that of AEDs that influence fast inactivation of the sodium channel.

Adjunctive pregabalin for uncontrolled partial-onset seizures: findings from a prospective audit

AIMS

Pregabalin (PGB) was licensed in Europe as an add-on antiepileptic drug (AED) for the treatment of partial-onset seizures in 2004. This audit assessed the response to adjunctive PGB in patients with uncontrolled seizures.

METHODS

PGB was titrated in 135 patients [73 men; 62 women, aged 18-76 (median 44 years) until one of the following occurred: ≥ 6 months' seizure freedom, ≥ 50% or < 50% seizure reduction over 6 months; PGB withdrawal because of adverse effects, lack of efficacy or both.

RESULTS

Of the 135 patients, 14 (10.4%) became seizure-free for ≥ 6 months (median PGB dose 300 mg/day; range 75-600 mg). A ≥ 50% seizure reduction occurred in 33 (24.4%) patients; 20 (14.8%) had < 50% reduction. PGB was withdrawn in 68 (50.4%) (40 adverse effects, seven lack of efficacy and 21 both). Commonest problems resulting in withdrawal were sedation (n = 18), weight gain (n = 14) and ataxia (n = 9). There was a positive correlation between increasing dose and weight gain (r = 0.42, P = 0.045).

CONCLUSIONS

Add-on PGB benefited 50% of patients, but only 10% achieved 6 months' seizure freedom. Adverse effects, most commonly sedation, dose-related weight gain and ataxia, led to drug discontinuation by 45%. Prospective audits of novel AEDs are a useful adjunct to randomized, controlled trials in managing epilepsy.