Ketter's hypothesis of the mood effects of antiepileptic drugs coupled to the mechanism of action of topiramate and levetiracetam

Does levetiracetam use affect visual evoked potentials in the treatment of childhood epilepsy?

BACKGROUND

Side effects of antiepileptic drugs vary depending on the drug itself, drug dose and duration of use. One of these side effects is related to vision.

METHODS

Patients who had been ordered visual evoked potential (VEP) measurements for various reasons between October 1st, 2017 and October 1st, 2019 at a pediatric neurology outpatient clinic and who were on levetiracetam monotherapy for at least six months for the treatment of focal/generalized epilepsy were included in the study and their files were scanned retrospectively (study group: SG). Patient files were evaluated for age, gender, dose and duration of levetiracetam use, presence of a family history of epilepsy, EEG result, cranial magnetic resonance imaging and VEP test results and the parameters were recorded. Twenty-four patients of similar age range without epilepsy were included in the study as the control group (CG).

RESULTS

Eighteen patients 8 boys (44.4%), 10 girls (55.6%) and 24 healthy controls 9 boys (37.5%), 15 girls (62.5%) were included in the study and control groups, respectively. No statistically significant difference was found when the mean VEP latencies were compared between the patient and control groups for the right (P=0.451) and left (P=0.323) eyes. There was a statistically significant difference between the groups, respectively, when VEP amplitudes of the right and left eyes of the SG and CG were compared (P=0.001; P=0.001). There is no correlation between levetiracetam dose and duration of treatment and VEP parameters.

CONCLUSIONS

The data obtained in this study showed that levetiracetam use affected VEP amplitude outcome but did not affect VEP latency outcome in pediatric patients.

Topiramate's effectiveness on weight reduction in overweight/obese persons with schizophrenia: study protocol for a randomized controlled trial

BACKGROUND

Schizophrenia is a psychiatric disorder with a higher mortality than that of the general population. Most of the deaths are due to cardiovascular causes and are related to metabolic risks. This risk is due not only to antipsychotics but also to inherent factors of the disorder. Studies in the West have shown topiramate to be effective in schizophrenia to reduce weight gain and for symptomatic control. Whether this is effective for South Asians is not known. It is important because South Asians have a higher risk of metabolic syndrome. We aim to conduct a double-blind, randomized controlled trial comparing topiramate add-on therapy with treatment as usual with antipsychotics in patients with schizophrenia in an outpatient setting in Sri Lanka.

METHODS/DESIGN

Ninety patients with schizophrenia presenting to the Colombo North Teaching Hospital will be randomized to intervention and control groups equally using permuted block randomization. Patients with comorbid metabolic disorders and taking prescribed weight-controlling medications will be excluded. The intervention group will be prescribed topiramate in addition to their antipsychotics in a predefined dosing regimen targeting a dose of 100 mg per day. The control subjects are to receive a placebo. As the primary outcome, anthropometric measurements including weight, waist circumference, skinfold thickness, and body mass index will be recorded at baseline and monthly during the study period of 3 months. The secondary outcome is the change in symptoms according to the clinician-administered Brief Psychiatric Rating Scale. Assessment of capacity will be performed and informed consent obtained from all subjects. Ethics approval has been obtained from the ethical review committee of the Faculty of Medicine, University of Kelaniya, and the trial has been registered in the Sri Lanka Clinical Trials Registry.

DISCUSSION

In this double-blind, randomized controlled trial, we will attempt to assess the effectiveness of topiramate as an add-on therapy compared with treatment as usual for weight control in patients with schizophrenia. To our knowledge, this is the first such study in South Asia, where metabolic risks are found to be higher than in the West and could have unique ethnic factors related to weight gain in schizophrenia.

TRIAL REGISTRATION

Sri Lanka Clinical Trials Registry, SLCTR/2017/003 . Registered on 20 February 2017. Universal trial number, U1111-1192-9439.

Modulation of ion channels in clinical psychopharmacology: adults and younger people

This review focuses on the use of Na(+), Ca(2+) and Cl(-) channel modulators in psychiatric disease. Drugs that modulate ion channels have been used in psychiatry for more than a century, and in this review we critically evaluate clinical research that reports the therapeutic effects of drugs acting on GABA(A), voltage-gated Na(+) and voltage-gated Ca(2+) channels in pediatric and adult patients. As in other fields, the evidence underpinning the use of medicines in younger people is far less robust than for adults. In addition, we discuss some current developments and highlight clinical disorders in which current molecules could be further tested. Notable success stories, such as benzodiazepines (in sleep and anxiety disorders) and antiepileptics (in bipolar disorder), have been the result of serendipitous discoveries or refinements of serendipitous discoveries, as in all other major treatments in psychiatry. Genomic, high-throughput screening and molecular pharmacology discoveries may, however, guide further developments in the future. This could include increased research in promising targets that have been perceived as commercially risky, such as selective α-subunit GABA(A) receptors.

Levetiracetam: a review of its use in epilepsy

Levetiracetam (Keppra®, E Keppra®) is an established second-generation antiepileptic drug (AED). Worldwide, levetiracetam is most commonly approved as adjunctive treatment of partial onset seizures with or without secondary generalization; other approved indications include monotherapy treatment of partial onset seizures with or without secondary generalization, and adjunctive treatment of myoclonic seizures associated with juvenile myoclonic epilepsy and primary generalized tonic-clonic (GTC) seizures associated with idiopathic generalized epilepsy. Levetiracetam has a novel structure and unique mechanisms of action. Unlike other AEDs, the mechanisms of action of levetiracetam appear to involve neuronal binding to synaptic vesicle protein 2A, inhibiting calcium release from intraneuronal stores, opposing the activity of negative modulators of GABA- and glycin-gated currents and inhibiting excessive synchronized activity between neurons. In addition, levetiracetam inhibits N-type calcium channels. Levetiracetam is associated with rapid and complete absorption, high oral bioavailability, minimal metabolism that consists of hydrolysis of the acetamide group, and primarily renal elimination. It lacks cytochrome P450 isoenzyme-inducing potential and is not associated with clinically significant pharmacokinetic interactions with other drugs, including other AEDs. The efficacy of oral immediate-release levetiracetam in controlling seizures has been established in numerous randomized, double-blind, controlled, multicentre trials in patients with epilepsy. Adjunctive levetiracetam reduced the frequency of seizures in paediatric and adult patients with refractory partial onset seizures to a significantly greater extent than placebo. Monotherapy with levetiracetam was noninferior to that with carbamazepine controlled release in controlling seizures in patients with newly diagnosed partial onset seizures. Levetiracetam also provided seizure control relative to placebo as adjunctive therapy in patients with idiopathic generalized epilepsy with myoclonic seizures or GTC seizures. In addition, patients receiving oral levetiracetam showed improvements in measures of health-related quality of life relative to those receiving placebo. Although treatment-emergent adverse events were commonly reported in the clinical trials of levetiracetam, the overall proportion of patients who experienced at least one treatment-emergent adverse event was broadly similar in the levetiracetam and placebo treatment groups, with most events being mild to moderate in severity. Levetiracetam is not associated with cognitive impairment or drug-induced weight gain, but has been associated with behavioural adverse effects in some patients.

The impact of side effects on long-term retention in three new antiepileptic drugs

OBJECTIVE

To determine long-term retention, percentage of patients withdrawing because of adverse events, percentage of patients achieving seizure freedom, safety profile of the new anti-epileptic drugs lamotrigine, levetiracetam and topiramate.

METHODS

All patients treated with lamotrigine, levetiracetam or topiramate in the Epilepsy Centre were identified. Each drug was analyzed from introduction of the drug in the Netherlands up to a final assessment point 2 years later.

RESULTS

Data from 1066 patients were included: 336 for lamotrigine, 301 for levetiracetam, 429 for topiramate. Two-year retention rates were 69.2% (lamotrigine), 45.8% (levetiracetam), 38.3% (topiramate); (LTG vs. LEV at p<0.001; LTG vs. TPM at p<0.001; LEV vs. TPM at p=0.005). Seizure freedom rates were lowest for lamotrigine and highest for levetiracetam. Adverse events played a role in drug discontinuation in 154/429 patients (35.9%) on topiramate, 52/336 patients (15.5%) on lamotrigine (p<0.001), 68/301 patients (22.5%) on levetiracetam (p<0.001). Mood and general CNS-effects are common in patients on lamotrigine and levetiracetam, and neurocognitive side effects are most prevalent in patients on topiramate. A positive effect on cognition is frequently noted in patients on lamotrigine.

CONCLUSION

A drug that is only modestly efficacious but has a favourable safety profile may look better than a drug that is more efficacious but produces clinically meaningful adverse events. Therefore, a drug's retention rate is mainly determined by its side effect profile. As a consequence, retention rate was highest for lamotrigine and lowest for topiramate. Intermediate retention rates were seen with levetiracetam use.

Long-term effects of levetiracetam and topiramate in clinical practice: A head-to-head comparison

OBJECTIVE

Two of the most commonly prescribed new antiepileptic drugs as add-on therapy for patients with chronic refractory epilepsies are topiramate and levetiracetam. In regulatory trials, both drugs were characterized as very promising new antiepileptic drugs. However, results from these highly controlled short-term clinical trials cannot simply be extrapolated to everyday clinical practice, also because head-to-head comparisons are lacking. Therefore, results from long-term open label observational studies that compare two or more new AEDs are crucial to determine the long-term performance of competing new antiepileptic drugs in clinical practice.

METHOD

We analyzed all patients referred to a tertiary epilepsy centre who had been treated with topiramate from the introduction of the drug in spring 1993 up to a final assessment point mid-2002 and all patients who had been treated with LEV in the same centre from the introduction of the drug in early 2001 up to a final assessment point end-2003 using a medical information system.

RESULTS

Three hundred and one patients were included for levetiracetam and 429 patients for TPM. Retention rate after 1 year was 65.6% for LEV-treated patients and 51.7% for TPM-treated patients (p=0.0015). Similarly, retention rates for LEV were higher at the 24-month mark: 45.8% of LEV-treated patients and 38.3% of TPM-treated patients were still continuing treatment (p=0.0046). Adverse events led to drug discontinuation in 21.9% of TPM-treated patients compared to 6.0% of LEV-treated patients (p<0.001). The number of patients discontinuing treatment because of lack of efficacy was similar for both groups. Seizure freedom rates varied between 11.6 and 20.0% for TPM and between 11.1 and 14.3% for LEV per 6-months interval. Several important AED specific adverse events leading to drug discontinuation were identified, including neurocognitive side effects from TPM and mood disorders from LEV.

CONCLUSION

The retention rate for LEV is significantly higher than for TPM. LEV had a more favourable side effect profile than TPM with comparable efficacy. Patients on TPM discontinued treatment mainly because of neurocognitive side effects. In the treatment with LEV, the effects on mood must not be underestimated.

Potential of levetiracetam in mood disorders: a preliminary review

Levetiracetam is a newer antiepileptic agent that was first approved by the US FDA in 1999 as an adjunctive therapy for the treatment of refractory partial epilepsy in adults. Since then, it has been approved for a wider patient population, i.e. as adjunctive therapy for partial seizures in patients >4 years of age (worldwide) and as first-line monotherapy for partial seizures in patients >16 years of age (in Europe); and as adjunctive therapy for juvenile myoclonic seizures (in Europe and the US). It has a favourable pharmacokinetic profile and appears to act at a specific site in the CNS. Pharmacodynamic evidence indicates that levetiracetam indirectly facilitates GABAergic function, and an increasing body of evidence suggests an important role for GABA in the pathophysiology of mood disorders. Preclinical studies using animal models of depression, anxiety and mania provide evidence for levetiracetam as a mood stabiliser. Preliminary clinical evidence from case reports and open-label pilot studies indicates that the drug, both as add-on therapy and as monotherapy, has efficacy in a wide range of bipolar spectrum disorders. Most recently, a 31% remission rate was reported in patients with bipolar disorder who were in the depressed phase at baseline and who received levetiracetam as add-on therapy for 8 weeks in an open-label trial. While these results are encouraging, placebo-controlled data are needed to further clarify the role of levetiracetam in the treatment of mood disorders.

Levetiracetam in clinical practice: long-term experience in patients with refractory epilepsy referred to a tertiary epilepsy center

OBJECTIVE

For the treatment of patients with chronic refractory epilepsies, development of new antiepileptic drugs is crucial. Three regulatory trials have demonstrated that add-on levetiracetam is efficacious in patients with localization-related epilepsy. However, results from these highly controlled short-term clinical trials cannot simply be extrapolated to everyday clinical practice. Therefore, more information is needed about the long-term profile of a new antiepileptic drug in clinical practice.

METHOD

We analyzed all patients who had been treated with levetiracetam in the Epilepsy Centre Kempenhaeghe from the introduction of the drug in early 2001 up to a final assessment point, at the end of 2003, using a medical information system.

RESULTS

In total, 301 patients were included. One hundred thirty-eight patients (45.8%) discontinued LEV treatment during the 24-month follow-up period. Reasons for discontinuation were lack of efficacy in 15.9% of patients, adverse events in 6.0% of patients, and a combination of lack of efficacy and adverse events in 16.3% of patients. By Kaplan-Meier survival analysis, the continuation rate was 65.6% after 1 year and 45.8% after 2 years. About 15% of patients in this highly refractory group had a 3-month remission, whereas 10% of patients became seizure-free for longer periods. The most frequently reported side effects at the time of discontinuation were mood disorders, tiredness, and sleepiness. Variables predicting (dis)continuation of levetiracetam treatment could not be identified.

CONCLUSION

Levetiracetam is a new antiepileptic drug that appears to be a useful add-on treatment in patients with refractory epilepsy. Its side effect profile is mild, with mood disorders being the most dominant adverse event.