Efficacy and safety of levetiracetam 1000-3000 mg/day in patients with refractory partial-onset seizures: a multicenter, open-label single-arm study

Therapeutic potential of ketamine in management of epilepsy: Clinical implications and mechanistic insights

Epilepsy, a widespread neurological disorder, affects approximately 50 million people worldwide. This disorder is typified by recurring seizures due to abnormal neuron communication in the brain. The seizures can lead to severe ischemia and hypoxia, potentially threatening patients' lives. However, with proper diagnosis and treatment, up to 70 % of patients can live without seizures. The causes of epilepsy are complex and multifactorial, encompassing genetic abnormalities, structural brain anomalies, ion channel dysfunctions, neurotransmitter imbalances, neuroinflammation, and immune system involvement. These factors collectively disrupt the crucial balance between excitation and inhibition within the brain, leading to epileptic seizures. The management of treatment-resistant epilepsy remains a considerable challenge, necessitating innovative therapeutic approaches. Among emerging potential treatments, ketamine-a drug traditionally employed for anesthesia and depression-has demonstrated efficacy in reducing seizures. It is noteworthy that, independent of its anti-epileptic effects, ketamine has been found to improve the balance between excitatory and inhibitory (E/I) activities in the brain. The balance is crucial for maintaining normal neural function, and its disruption is widely considered a key driver of epileptic seizures. By acting on N-methyl-D-aspartate (NMDA) receptors and other potential mechanisms, ketamine may regulate neuronal excitability, reduce excessive synchronized neural activity, and counteract epileptic seizures. This positive impact on E/I balance reinforces the potential of ketamine as a promising drug for treating epilepsy, especially in patients who are insensitive to traditional anti-epileptic drugs. This review aims to consolidate the current understanding of ketamine's therapeutic role in epilepsy. It will focus its impact on neuronal excitability and synaptic plasticity, its neuroprotective qualities, and elucidate the drug's potential mechanisms of action in treating epilepsy. By scrutinizing ketamine's impact and mechanisms in various types of epilepsy, we aspire to contribute to a more comprehensive and holistic approach to epilepsy management.

Dosage, time, and polytherapy dependent effects of different levetiracetam regimens on cognitive function

OBJECTIVE

Cognitive impairment is a potential drawback of antiseizure medications. This study aimed to evaluate the impact of different levetiracetam drug regimens on cognitive function.

METHODS

A retrospective analysis identified 221 patients diagnosed with seizures who underwent cognitive screening. Patients were categorized into four groups: no medications, non-levetiracetam medications, high and low dose levetiracetam. Composite scores determined low and high levetiracetam groups whereby one point was added for each increment in dosage, duration since uptake, and concurrent anti-seizure medication. Variables known to affect cognition were recorded and classified as demographic, seizure-related, diagnosis-related, and psychopathology. Logistic regression was used to identify variables associated with cognitive scores below cut-off.

RESULTS

Multivariable analysis found being male, non-active in the community, less than 12 years of education, left temporal lobe epilepsy, high seizure frequency, and depression were associated with poor cognitive performance. In a final regression analysis, the high levetiracetam group exhibited a 4.5-fold higher likelihood of scoring below cut-off than the medication-free group (OR 4.5, CI 1.5-13.6, p<.08). Depression (OR 2.1, CI 1.1-3.9, p<.03), being male (OR 2.2, CI 1.1-4.3, p<.02), and not being active in the community (OR 3.8, 1.6-8.7, p <.003) remained significant contributors to the model. Language (p<.05), attention (p<.05), and delayed recall (p<.001) were the most affected cognitive domains.

SIGNIFICANCE

When taken in small doses, for brief periods as monotherapy, levetiracetam minimally influences cognition. At higher doses, as part of long-term seizure management, in conjunction with multiple ASMs, LEV is associated with cognitive impairment.

Multifocal myoclonus as a presentation of levetiracetam toxicity

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Levetiracetam (LEV) is a widely used antiseizure medication, but LEV toxicity is not commonly reported.

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We report a patient with chronic kidney disease who developed multifocal myoclonus after treatment with LEV.

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The findings suggest the possibility of an inverted U-shaped dose–response of the anti-myoclonic effect of LEV.

Background

Levetiracetam (LEV) is widely used for treatment of focal and myoclonic seizures, but reports of LEV toxicity are scarce. Here, we report a rare case of multifocal myoclonus due to LEV toxicity in a patient with chronic renal insufficiency.

Case presentation

A 52-year-old woman with history of chronic kidney disease was admitted to the ICU for sedation and intubation after a cardiac arrest. She developed nonconvulsive status epilepticus that resolved after administration of propofol while receiving LEV 1500 mg twice a day. After holding the propofol infusion, the patient started having multifocal myoclonic jerks, documented on video-EEG recordings with a supratherapeutic level of LEV. After discontinuation of LEV, the myoclonus resolved.

Conclusion

This is a unique manifestation of LEV toxicity, which has been scarce in the literature. It suggests an inverted U-shaped dose–response of the antimyoclonic effect of LEV.

Acute Kidney Injury Caused by Levetiracetam in a Patient With Status Epilepticus

Levetiracetam is a widely used, effective and usually well-tolerated anti-epileptic medicine. It is mostly excreted by kidneys and requires dose adjustment according to the glomerular filtration rate. Very few case reports have been published in the literature about levetiracetam causing acute kidney injury (AKI). We present a case of a 26-year-old male with a seizure disorder on levetiracetam, presented with status epilepticus requiring intubation for airway protection. He received 4 g of intravenous levetiracetam as a loading dose and continued with a maintenance dose of 750 mg intravenous every 12 hours. He had signs of AKI on day two and creatinine eventually reached a maximum level of 12.2 mg/dL. His kidney function improved to his new baseline in a period of 30 days without requiring renal replacement therapy. He did not have significant rhabdomyolysis and his kidney function started improving right after his anti-epileptic therapy was switched to valproic acid pointing towards levetiracetam as the primary cause of kidney injury. Clinicians should be aware that levetiracetam can cause AKI on patients with a seizure disorder, especially when administered in high doses. Kidney function should be monitored closely and patients should be treated aggressively with intravenous fluids when they have any signs of rhabdomyolysis to prevent further kidney damage.

Fatigue during treatment with antiepileptic drugs: A levetiracetam-specific adverse event?

PURPOSE

To examine the prevalence and clinical correlates of fatigue as an adverse event (AE) of antiepileptic drug (AED) treatment in patients with epilepsy.

METHODS

Data from 443 adult outpatients with epilepsy assessed with the Adverse Event Profile (AEP) and the Neurological Disorder Depression Inventory for Epilepsy (NDDIE) were analysed.

RESULTS

Fatigue is reported by 36.6% of patients as always a problem during AED treatment. Fatigue is more likely to be reported by females (64.8% vs. 35.2%; Chi-Square=16.762; df=3; p=0.001) and during treatment with levetiracetam (42.3% vs. 33.2%; Chi-Square=11.462; df=3; p=0.009). The associations with the female gender and levetiracetam treatment were not mediated by depression, as identified with the NDDIE, and could not be simply explained by the large number of subjects on levetiracetam treatment, as analogous figures resulted from the analysis of a monotherapy subsample (41.7% vs. 30.3%; Chi-Square=11.547; df=3; p=0.009).

CONCLUSIONS

One third of patients with epilepsy reports fatigue as a significant problem during AED treatment. Fatigue is more likely to be reported by females and seems to be specifically associated with LEV treatment. However, fatigue is not mediated by a negative effect of LEV on mood.

Justification for conducting neurological clinical trials as part of patient care within private practice

The aim of this review was to assess the benefits and drawbacks of conducting neurological clinical trials and research in private practice for the patients, clinician, Practice Manager, sponsors/Clinical Research Organisations (CROs) and Clinical Trial Coordinator (CTC) to determine if this is justified for all involved. A combination of literature reviews, original research articles and books were selected from 2005 to 2015. Provided that the practice has sufficient number of active trials to prevent financial loss, support staff, adequate facilities and equipment and time, the benefits outweigh the drawbacks. Clinical trials provide patients with more thorough monitoring, re-imbursement of trial-related expenses and the opportunity to try an innovative treatment at no charge when other options have failed. For the clinician, clinical trials provide more information to ensure better care for their patients and improved treatment methods, technical experience and global recognition. Trials collect detailed and up-to-date information on the benefits and risks of drugs, improving society's confidence in clinical research and pharmaceuticals, allow trial sponsors to explore new scientific questions and accelerate innovation. For the CTC, industry-sponsored clinical trials allow potential entry for a career in clinical research giving CTCs the opportunity to become Clinical Research Associates (CRAs), Study Start-Up Managers or Drug Safety Associates.

Neutropenia Secondary to Exposure to Levetiracetam

Aims and background

Brain metastases occur in about 30% of patients with non-small-cell lung carcinoma; seizures occur in approximately 20% of them. Antiepileptic drugs are commonly given for postoperative prophylaxis after brain or metastasis tumor surgery. The incidence of seizures following supratentorial craniotomy is estimated to be 15%-20%. Postoperative seizures are more common in the first month after cranial surgery. However, the use of antiepileptic drugs postoperatively has been investigated in randomized controlled trials. In case of seizures, the recommendations are continuing antiepileptic drugs after a 1- to 4-year seizure-free interval. This decision must weigh the risk of seizure recurrence against the possible benefits of the drug. Some antiepileptic drugs have been known to cause blood dyscrasias, including neutropenia, but this is a rare occurrence.

Methods

We report a case of neutropenia related to the use of levetiracetam at first exposure. After drug administration, neutropenia was detected. Additional tests were performed.

Results

By exclusion, it was decided to withdraw the drug, and the patient had a reversal of neutropenia.

Conclusions

Levetiracetam-induced neutropenia is infrequent but possible. It is an exclusion diagnosis.

The benefits of antiepileptic drug (AED) blood level monitoring to complement clinical management of people with epilepsy

INTRODUCTION

Some argue that there is no evidence to support the use of antiepileptic drug (AED) blood level monitoring when treating people with epilepsy (PWE). This paper identifies how AED monitoring can be invaluable in such treatment. SPECIFIC EXAMPLES: (i) Compliance: Antiepileptic drug blood levels often confirm noncompliance rather than adequate seizure control, confirming subtherapeutic levels in PWE attending hospitals due to seizures. Routine monitoring of AED levels may prevent breakthrough seizures by identifying noncompliance and instituting heightened compliance measures before experiencing breakthrough seizures without modifying dosages. For PWE attending hospitals due to seizures, loading with the AED shown to be subtherapeutic may be all that is required. (ii) Cluster seizures and status epilepticus: When using long-acting AEDs to complement benzodiazepines, blood level monitoring confirms that an adequate dosage was given and, if not, a further bolus can be administered with further monitoring. This is particularly useful when using rectal administration of AEDs. (iii) Polypharmacy: Polypharmacy provokes drug interactions in which case AED monitoring helps in differentiating adequate dosing, offending AED with toxicity and free level measuring benefits when total levels are unhelpful. (iv) Generic substitution: Generic AEDs can fluctuate considerably from a parent compound, and even a parent compound, sourced from an alternative supplier, may have altered bioavailability for which blood level monitoring is very useful.

CONCLUSIONS

While therapeutic blood level monitoring is not a substitute for good clinical judgment, it offers a valuable adjunct to patient care.

Long-term accidental overdose of levetiracetam in an infant

Levetiracetam is one of the new anticonvulsant drugs that has a high therapeutic index and potential antiepileptogenic effects. Herein, we report a patient with multidrug refractory epilepsy and Ohtahara syndrome who was accidentally administered 300 mg/kg/d for 35 days by her mother. To our knowledge, there are only a few cases of accidental overdose of levetiracetam in pediatric patients reported in the literature, and this case study is the first to report such a high and long-term dose in an infant who showed no adverse effects.

A review on antiepileptic drugs-dependent fatigue: pathophysiological mechanisms and incidence

Fatigue represents a common side effect of several drugs, however, the underlying mechanisms have not been well identified. A depression of the central nervous system (CNS) and/or changes in peripheral processes have been associated with the development of fatigue. Antiepileptic drugs (AEDs), generally decreasing CNS excitability, are used in the treatment of seizures as well as other neurological and psychiatric diseases. Fatigue is certainly a common AEDs' side effect, although a high degree of variability exists depending on both patients' characteristics and the drug used. Here, we delineate the pathophysiological central and peripheral mechanisms by which AEDs may cause fatigue also reviewing the available clinical data in order to assess a possible AEDs rank and highlight each AEDs related risk. It appears that drugs acting on the GABAergic system have the highest incidence (with tiagabine exception) of fatigue followed by Gabapentin and Levetiracetam whereas drugs mainly inhibiting sodium channels (Carbamazepine, Eslicarbazepine, Lamotrigine, Phenytoin and Valproate) have the lowest. However, the dose used, AEDs related side effects and patients' characteristics might influence the degree of fatigue observed.

Treatment of recurrent epileptic seizures in patients with neurological disorders

This study aimed to investigate the clinical characteristics and the treatment principles and methods of recurrent epileptic seizures in patients with neurological disorders. A retrospective analysis was performed of the clinical data, treatment methods and results in 13 patients with recurrent epileptic seizures attending the neurosurgery department. Of the 13 patients, 10 had a history of epilepsy, 9 had organic frontal lobe brain lesions and 11 exhibited frontal lobe epilepsy. The causes of the epileptic seizure aggravation included drug withdrawal, dose reduction and dressing change (5 cases). The epileptic seizure types included partial and secondary full seizures and the seizure frequency ranged from 1 seizure/3 min to 1 seizure/several h. Following combined therapy with multiple anti-epileptic drugs (AEDs), including oral administration and injection, the epilepsy was controlled. The addition of orally administered levetiracetam improved the treatment efficiency. In cases of recurrent epileptic seizures in patients with neurological disorders, the combined administration of AEDs should be conducted with doses higher than the conventional initial dose to control the epileptic seizures as rapidly as possible.

Epilepsy-related employment prevalence and retirement incidence in the German working population: 1994-2009

Epilepsy-related employment prevalence and retirement incidence were investigated in the German working population from 1994 to 2009. The overall mean prevalence of employment of people with epilepsy was 5.1±0.2 per 1000 workers. The employment rate among people with epilepsy increased from 63.5% in 1994 to 65.9% in 2000 (0.4% annually) and then more steeply from 66.8% in 2001 to 76.9% in 2009 (1.4% annually). A prominent increase in rate of employment of people with epilepsy since 2001 was temporarily associated with approval of leviteracetam in 2000 (P<0.001, OR=8.3, CI=6.45-10.12). The overall mean employment rate of people with epilepsy was lower than that of the general population (68.5% vs 90.1%, P<0.001). The overall mean incidence of epilepsy-related retirement (RI) during the study was 4.6±1.6/1000, similar to the RI for people with other illnesses (5.1±0.8/1000), and the risk of retiring because of epilepsy was not higher than that for other illnesses over the entire study period (P=0.52, OR=1.11, CI=0.86-1.43). The RI among workers with epilepsy, however, sharply declined from 8.3/1000 in 1994 to 2.9/1000 in 2000 (-65%, < 0.001), followed by a slight increase and stabilization at 3.9/1000 workers between 2001 and 2009. The decline in RI among people with epilepsy was temporarily associated with legislation of the Law on Support of Employment in 1996 (P=0.032, OR=2.15, CI=1.17-2.89) and approval of lamotrigine in 1993 (P=0.024, OR=2.64, CI=2.17-3.88). These patterns suggest that drug treatment and legislative laws may have led to increased employment and reduced retirement rates for people with 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.

Levetiracetam reduces myoclonus in corticobasal degeneration: report of two cases

Levetiracetam (LEV) has been shown to suppress myoclonus of various origins. Corticobasal degeneration (CBD), a progressive neurodegenerative disorder with Parkinsonian syndrome, is frequently accompanied by myoclonus. We investigated the effect of LEV on myoclonus in two CBD patients. LEV remarkably decreased the myoclonic activity in both patients already at 1,500 mg/day dose. This is the first report on LEV alleviating myoclonus in CBD. Our data indicate that it might be worthwhile to assess this effect in an appropriately designed study.

The effects of levetiracetam on cognition: a non-interventional surveillance study

Objective and subjective cognitive measures were evaluated in 401 patients before and 3 and 6 months after introducing levetiracetam (LEV). Initially, cognitive impairment was indicated in 37-44% of the patients, and subjective impairments in 32-67%. With LEV, 87% of untreated patients changed to monotherapy, and 94% changed from mono- to polytherapy. The rate of retention of LEV was 97%; adverse events were reported by 7%. Under LEV, 36% achieved early seizure control, 25% achieved late seizure control, 33% continued to have seizures, and 7% had a relapse. Very good tolerance was reported by 68%, and cognitive improvement by 58%. Objective improvement was significant in 23-29% of the patients; 5-6% deteriorated. Better baseline scores, later-onset epilepsies, fewer initial antiepileptic drugs, and seizure control were predictive of a better cognitive outcome. Considering the uncontrolled study design and the increase in total drug load, LEV appeared safe and efficacious, and a general subjective and objective cognitive improvement could be noted. However, a controlled study design would be required to attribute these improvements to a specific drug action.

Thrombocytopenia during levetiracetam therapy

A 64-year-old patient with symptomatic epilepsy developed thrombocytopenia during treatment with levetiracetam (LEV). As no other medical reason could be evaluated, a medication side effect was postulated. The only new drugs were valproic acid (since 3 weeks) and levetiracetam (since 3 days). After valproic acid medication was ended, thrombocytopenia did not improve and even worsened further. Finally levetiracetam administration was ended and trombocytopenia resolved rapidly and completely within few days.

Positive and negative psychotropic effects of levetiracetam

OBJECTIVES

The goals of this study were to observe behavioral changes in patients receiving levetiracetam (LEV), a newer antiepileptic drug (AED), and to answer the question of whether LEV exerts a specific effect on impulse control and aggression.

METHODS

We asked 288 consecutive patients with epilepsy on LEV (90% polytherapy, mean dose=2689 mg) and 135 relatives whether LEV caused a positive or negative behavioral change. Forty-three patients on other AEDs served as a control group. Ratings were related to patient characteristics, efficacy, dose, drug load, bidirectional ratings of change in behavioral domains, and questionnaires on personality (Fragebogens zur Persönlichkeit bei zerebralen Erkrankungen) and impulsivity (Barratt Impulsiveness Scale-11).

RESULTS

LEV was rated as very effective by 40% of the patients. In contrast to only 9% of the controls, a considerable number of patients reported a behavioral change while taking LEV (12% very negative, 25% negative, 16% positive, 6% very positive). Negative ratings were due to loss of self-control, restlessness, sleep problems, and, most importantly, aggression. Positive ratings were due to increased energy, vigilance, and activation. Increases in psychomotor speed, concentration, and remote memory indicated subjectively experienced positive effects on cognition. The proxy reports indicated reliable self-reports. Reported change was not related to type of epilepsy, co-therapy, dose, drug load, or psychiatric history. Negative effects were, however, associated with poorer seizure control, mental retardation, indicators of an organic psychosyndrome, and nonplanning impulsiveness.

CONCLUSION

The results indicate that LEV exerts a dose-independent stimulating effect that can be positive or negative. Aggression is a prominent feature. Lack of efficacy, mental retardation, and presumably also pre-intake disposition (organic psychosyndrome, impulsivity) may be helpful in predicting whether additional activation under LEV will be positive or negative.

Value of therapeutic drug level monitoring and unbound (free) levels

Therapeutic drug monitoring (TDM) has declined with newer anti-epileptic drugs (AEDs) having no therapeutic window. Use of unbound (free) fraction has almost completely disappeared. The case reported highlights its importance and offers sound reason for its retention. A 66-year-old Caucasian man with known epilepsy was admitted with vomiting, ataxia and nystagmus presumably due to AED toxicity. Medications included valproate (VPA) 1g bd; phenytoin (PHT) 200mg tds; carbamazepine (CBZ) 400mg mane, 200mg midi, 400mg nocte; levetiracetam (LEV) 250mg bd. Initial AED-TDM revealed total serum levels of CBZ: 27micromol/L; PHT: 37micromol/L; VPA 499micromol/L, therapeutic or subtherapeutic. Free levels were subsequently measured demonstrating CBZ: 8.2micromol/L; PHT: 5micromol/L; VPA 93micromol/L. Consequently, VPA was initially omitted and dosage reduced with cessation of toxicity. AED regimen was greatly simplified and remained efficacious. This case highlights the value of TDM with polypharmacy and suggested AED toxicity. Total AED levels failed to identify the cause, which the unbound, free fraction identified. While total PHT was borderline subtherapeutic (37micromol/L; range: 40-80) the free level was therapeutic (5micromol/L; range: 4-8) and while VPA was therapeutic (VPA 499micromol/L; range: 300-750) the free level was supratherapeutic (93micromol/L; range: 30-75). Acknowledgement of discordance between total and free levels for highly protein-bound AED is highlighted.

The SKATE™ study: An open-label community-based study of levetiracetam as add-on therapy for adults with uncontrolled partial epilepsy

The Safety of Keppra as Adjunctive Therapy in Epilepsy (SKATE) study aimed to evaluate the safety and efficacy of levetiracetam (Keppra, LEV) as add-on therapy for refractory partial seizures in clinical practice. This Phase IV, 16-week, open-label study recruited patients > or =16-year old with treatment-resistant partial seizures. LEV (1000 mg/day) was added to a stable concomitant antiepileptic drug regimen. LEV dosage was adjusted based on seizure control and tolerability to a maximum of 3000 mg/day. 1541 patients (intent-to-treat population) were recruited including 1346 (87.3%) who completed the study and 77.0% who declared further continuing on LEV after the trial. Overall, 50.5% of patients reported at least one adverse event that was considered related to LEV treatment. The most frequently reported drug-related adverse events were mild-to-moderate somnolence, fatigue, dizziness and headache. Serious adverse events considered related to LEV occurred in 1.0% of patients. 7.5% of patients reported adverse events as the most important reason for study drug discontinuation. The median reduction from baseline in the frequency of all seizures was 50.2%; 15.8% of patients were seizure free; 50.1% had seizure frequency reduction of > or =50%. At the end of the study, 60.4% of patients were considered by the investigator to show marked or moderate improvement. There was a significant improvement in health-related quality of life as assessed with the QOLIE-10-P (total score increasing from 55.6 to 61.6; p<0.001). This community-based study suggests that LEV is well tolerated and effective as add-on therapy for refractory partial seizures in adults. These data provide supportive evidence for the safety and efficacy of LEV demonstrated in the pivotal Phase III placebo-controlled studies.

Efficacy and safety of levetiracetam as adjunctive treatment of refractory partial seizures in a multicentre open-label single-arm trial in Korean patients

This prospective, open-label study evaluated the efficacy and safety of adjunctive levetiracetam (LEV) in Korean adults with uncontrolled partial epilepsy. Study patients had to have an average of at least 1 and not more than 14 partial seizures per month (averaged over a 3-month historical baseline) despite the use of one or two AEDs. Patients initially received LEV 1000 mg/day (administered bid) and could increase to 2000 mg/day after 2 weeks, and to 3000 mg/day after another 2 weeks, to obtain adequate seizure control. During the 12-week maintenance period, the dose of LEV could be increased or decreased once if seizure control was insufficient or tolerability warranted, respectively. Seizure count and adverse events (AEs) were recorded by patients. Global evaluation scale (GES) and quality of life (QOLIE-31) were also evaluated. A total of 100 patients were enrolled and 92 patients completed the study. The median percent reduction in weekly seizure frequency over the treatment period was 43.2%. The >or=50% and >or=75% responder rates were 45.4% and 36.1%, respectively. Seizure freedom throughout the 16-week treatment period was observed in 17 patients. On investigator's GES, 81 patients were considered improved, with 41 patients showing marked improvement. Most QOLIE-31 scales improved significantly. Treatment-emergent AEs were reported in 59 patients. Three most common AEs were somnolence (36%), dizziness (12%), and headache (8%). Adjunctive LEV therapy was effective and well-tolerated in Korean adults with refractory partial epilepsy.

Single-dose pharmacokinetics of levetiracetam in healthy Chinese male subjects

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

* Levetiracetam has been evaluated for epilepsy since 1992. * Pharmacokinetic studies of levetiracetam have been conducted in healthy volunteers, in adults, children and elderly patients with epilepsy, and in patients with renal and hepatic impairment. * Although this antiepileptic has been well studied in Western countries, this paper describes the first such trial of the drug in a Chinese population.

WHAT THIS STUDY ADDS

* Information is given on the pharmacokinetics, dose proportionality, safety and tolerability profile of levetiracetam in healthy male Chinese volunteers, and the results are compared with published data obtained in White subjects. * The pharmacokinetics and the pattern of adverse events of levetiracetam in Chinese subjects are similar to the data reported in White subjects.

AIMS

The main aims of this study were to evaluate the pharmacokinetics of levetiracetam in healthy male Chinese volunteers and to assess the dose proportionality between the 500-mg and 1500-mg single doses.

METHODS

This was a randomized, single-centre, single-dose, two-way crossover study. Twenty-six healthy male Chinese subjects were enrolled. All subjects received a single dose of 500 mg or 1500 mg levetiracetam tablet(s) on the dosing day, and the wash-out period was 7 days. Blood was obtained for a 36-h pharmacokinetic evaluation.

RESULTS

Following single-dose administration of 500 mg and 1500 mg of levetiracetam, the median t(max) was 0.5 and 0.5 h; t(1/2) was 7.3 +/- 0.8 and 7.3 +/- 0.7 h; C(max) was 13.6 +/- 3.2 and 47.1 +/- 12.1 microg ml(-1); AUC(0-infinity) was 109.3 +/- 14.1 and 340.4 +/- 50.6 microg h(-1) ml(-1); and AUC(0-t) was 105.7 +/- 13.3 and 329.0 +/- 47.9 microg h(-1) ml(-1), respectively.

CONCLUSIONS

Both C(max) and AUCs were dose-proportional over the range of 500-1500 mg. The pharmacokinetic data obtained in these Chinese subjects were similar to the historical data from a matched group of White subjects.

Levetiracetam: past, present and future

Levetiracetam is an antiepileptic drug approved for use as an adjunctive agent in partial-onset seizures in adults. This approval was recently extended to children over 4 years of age. Among the currently approved antiepileptic drugs, levetiracetam is unique in its mechanism of action. Its CNS binding site, the synaptic vesicle protein SV2A, was discovered recently. Binding at this site may be important for the antiseizure activity of levetiracetam and the role of this binding site and its modulation by levetiracetam is an area of active research in epilepsy. Levetiracetam is generally safe, has near to ideal pharmacokinetics and does not interact with other medications. The most serious adverse events are behavioral in nature. Recent studies suggest that levetiracetam may be effective in generalized epilepsies, status epilepticus, pain and selected movement disorders. Intriguing studies using the kindling model of epilepsy suggest that levetiracetam may protect against the development of kindling and chronic epilepsy. A parenteral formulation of levetiracetam may soon become available and may lead to larger studies of levetiracetam in status epilepticus.

Benefit-Risk Assessment of Levetiracetam in the Treatment of Partial Seizures

Levetiracetam is a novel antiepileptic drug that has been demonstrated as being effective in the management of partial seizures. It is rapidly and completely absorbed after oral administration and it is predominantly eliminated as unchanged drug in the urine. Its metabolism is independent of the cytochrome P450 enzyme system, nor does it induce cytochrome P450 enzymes. As a result of its pharmacokinetic features, levetiracetam has not been demonstrated to interact with other drugs in either direction. In double-blind, placebo-controlled trials, all the levetiracetam dosages tested were effective, including 1000 mg/day, 2000 mg/day and 3000 mg/day. The ineffective dose is not known. Efficacy seemed to be maintained in long-term studies, with no evidence of tolerance. In major double-blind, placebo-controlled trials discontinuation rates because of adverse events were 6.9-10.9% for levetiracetam-treated patients (all doses) compared with 5.3-8.6% for placebo-treated patients. The most common adverse events that differed between treatment groups and placebo control groups were somnolence, asthenia, dizziness and, in the US study, infection. Since levetiracetam was marketed, behavioural effects have been reported, namely irritability, agitation, anger and aggressive behaviour. These adverse effects are more likely in learning disabled individuals, those with prior psychiatric history and those with symptomatic generalised epilepsy. Overall, the risk has been estimated at 12-15%. Laboratory parameters overall seem to be not significantly affected by levetiracetam, although slight trends to lower white and red blood cell counts were detected in the studies. No organ toxicity has been described so far, with patient exposures exceeding 500,000. In summary, levetiracetam exhibits a very favourable safety profile in patients with partial onset seizures. Whereas somnolence, asthenia and dizziness were the most prominent adverse effects in clinical trials, behavioural adverse effects have generally been the most common reason for drug discontinuation in clinical practice.