Topiramate for juvenile myoclonic epilepsy

Topiramate and other kainate receptor antagonists for depression: A systematic review of randomized controlled trials

BACKGROUND

Depression is a common disorder that affects patients' quality of life and incurs health system costs. Due to the resistance to treat depression, better understanding of neurophysiology was considered; one of the implications is the glutamatergic system. This study aims to systematically review clinical trials investigating the antidepressant effects of kainate receptor antagonists.

METHODS

The study protocol was registered in PROSPERO (CRD42021213912). Scopus, ISI, Embase, PubMed, Cochrane Library, Google Scholar, and two trial registries were searched for randomized controlled trials on the effectiveness of topiramate, phenobarbital, and other ten barbiturates in depression. The difference with control groups in terms of changing depressive symptoms was the primary outcome.

RESULTS

Nine trials were identified, in which 784 patients were studied. The efficacy of thiopental was comparable to that of imipramine, with fewer side effects. When administered with electroconvulsive therapy, it had fewer to similar effects and fewer side effects than ketamine. Both monotherapy and adjunctive therapy with topiramate were effective and tolerable in treating depressed patients. Phenobarbital had therapeutic effects compared to imipramine and amitriptyline with fewer side effects.

CONCLUSION

Regarding the glutamatergic hypothesis of depression and obtained promising results, further studies of kainate receptor antagonists in high-quality trials are recommended. Given the high prevalence of depression in epileptic patients, more problems with its treatment, and the fact that the studied agents were anticonvulsants, it is recommended that future studies prioritize depressed-epileptic patients.

A palladium polyaniline complex: a simple and efficient catalyst for batch and flow Suzuki-Miyaura cross-couplings

A novel palladium polyaniline complex (Pd@PANI) was synthesized via a one-pot method using a low concentration of hydrogen peroxide (3 wt%) as a mild oxidant. Pd@PANI was employed to catalyze Suzuki-Miyaura cross-couplings with 0.11 ppm levels of palladium and high turnover numbers (up to 6.1 × 10⁴). Various aromatic halides and aromatic boric acids were used as reaction partners to prepare the biaryl compounds in high yields. Application of the method in the synthesis of D-fructose derivatives was also performed. Furthermore, the catalyst was evaluated under a flow process to provide the corresponding products in good yields with shorter residence times and lower temperatures in more convenient operations compared with the batch conditions.

Genetic generalized epilepsies in adults - challenging assumptions and dogmas

Genetic generalized epilepsy (GGE) syndromes start during childhood or adolescence, and four commonly persist into adulthood, making up 15-20% of all cases of epilepsy in adults. These four GGE syndromes are childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy and epilepsy with generalized tonic-clonic seizures alone. However, in ~20% of patients with GGE, characteristics of more than one syndrome are present. Novel insights into the genetic aetiology, comorbidities and prognosis of the GGE syndromes have emerged and challenge traditional concepts about these conditions. Evidence has shown that the mode of inheritance in GGE is mostly polygenic. Neuropsychological and imaging studies indicate similar abnormalities in unaffected relatives of patients with GGE, supporting the concept that underlying alterations in bilateral frontothalamocortical networks are genetically determined. Contrary to popular belief, first-line anti-seizure medication often fails to provide seizure freedom in combination with good tolerability. Nevertheless, long-term follow-up studies have shown that with advancing age, many patients can discontinue their anti-seizure medication without seizure relapses. Several outcome predictors have been identified, but prognosis across the syndromes is more homogeneous than previously assumed. Overall, overlap in pathophysiology, seizure types, treatment responses and outcomes support the idea that GGEs are not separate nosological entities but represent a neurobiological continuum.

Topiramate for juvenile myoclonic epilepsy

BACKGROUND

Topiramate is a newer broad-spectrum antiepileptic drug (AED). Some studies have shown the benefits of topiramate in the treatment of juvenile myoclonic epilepsy (JME). However, there are no current systematic reviews to determine the efficacy and tolerability of topiramate in people with JME. This is an update of a Cochrane Review first published in 2015, and last updated in 2019.

OBJECTIVES

To evaluate the efficacy and tolerability of topiramate in the treatment of JME.

SEARCH METHODS

For the latest update, we searched the Cochrane Register of Studies (CRS Web) on 26 August 2021, and MEDLINE (Ovid 1946 to 26 August 2021). CRS Web includes randomized or quasi-randomized controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP), the Cochrane Central Register of Controlled Trials (CENTRAL), and the Specialized Registers of Cochrane Review Groups, including Cochrane Epilepsy.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) investigating topiramate versus placebo or other AED treatment for people with JME, with the outcomes of proportion of responders and proportion of participants experiencing adverse events (AEs).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of identified records, selected studies for inclusion, extracted data, cross-checked the data for accuracy and assessed the methodological quality of the studies.

MAIN RESULTS

We included three studies with a total of 83 participants. For efficacy, a greater proportion of participants in the topiramate group had a 50% or greater reduction in primarily generalized tonic-clonic seizures (PGTCS), compared with participants in the placebo group (RR 4.00, 95% CI 1.08 to 14.75; 1 study, 22 participants; very low-certainty evidence). There were no significant differences between topiramate and valproate for participants responding with a 50% or greater reduction in myoclonic seizures (RR 0.88, 95% CI 0.67 to 1.15; one study, 23 participants; very-low certainty evidence) or in PGTCS (RR 1.22, 95% CI 0.68 to 2.21; one study, 16 participants, very-low certainty evidence), or participants becoming seizure-free (RR 1.13, 95% CI 0.61 to 2.11; one study, 27 participants; very-low certainty evidence). Concerning tolerability, we ranked AEs associated with topiramate as moderate to severe, while we ranked 59% of AEs linked to valproate as severe complaints (2 studies, 61 participants; very low-certainty evidence). Moreover, systemic toxicity scores were higher in the valproate group than the topiramate group. Overall we judged all three studies to be at high risk of attrition bias and at unclear risk of reporting bias. We judged the studies to be at low to unclear risk of bias for the remaining domains (selection bias, performance bias, detection bias and other bias). We judged the overall certainty of the evidence for the outcomes as very low using the GRADE approach.

AUTHORS' CONCLUSIONS

We have found no new studies since the last version of this review was published in 2019. This review does not provide sufficient evidence to support topiramate for the treatment of people with JME. Based on the current limited available data, topiramate seems to be better tolerated than valproate, but has no clear benefits over valproate in terms of efficacy. Well-designed, double-blind RCTs with large samples are required to test the efficacy and tolerability of topiramate in people with JME.

Influence of Topiramate on the Synaptic Endings of the Temporal Lobe Neocortex in an Experimental Model of Hyperthermia-Induced Seizures: An Ultrastructural Study

The objective of this pioneering study was to assess potentially neuroprotective properties of topiramate (TPM), a broad spectrum and newer-generation antiepileptic used against damage to synaptic endings of the temporal lobe neocortex in experimental hyperthermia-induced seizures (HS). TPM (80 mg/kg b.m.) was administered in young male Wistar rats with an intragastric tube before and immediately after HS. Specimens (1 mm³) collected from the neocortex, fixed via transcardial perfusion with paraformaldehyde and glutaraldehyde solution, were routinely processed for transmission-electron microscopic study, i.e., for descriptive and morphometric analysis. The ultrastructure of neocortical neuropil components affected by hyperthermic stress showed distinct swelling of pre and post-synaptic axodendritic and axospinal endings, including total disintegration. Mitochondria were markedly damaged in synaptic structures. Axoplasm of presynaptic boutons contained a decreased number of synaptic vesicles. Synaptic junctions showed active zone-shortening. Preventive administration of TPM before HS induction demonstrated neuroprotective effects against synaptic damage in approximately 1/4 of these structures. Interestingly, beneficial effects on synapsis morphology were more common in perivascular zones close to well-preserved capillaries. They were demonstrated by smaller swelling of both presynaptic and postsynaptic parts, well-preserved mitochondria, an increased number and regular distribution of synaptic vesicles within axoplasm, and a significantly increased synaptic active zones. However, topiramate used directly after HS was ineffective in the prevention of hyperthermia-evoked synaptic injury. Our findings support the hypothesis that topiramate applied before HS can protect some neocortical synapses via the vascular factor by enhancing blood-brain barrier components and improving the blood supply of gray matter in the temporal lobe, which may be significant in febrile seizure-prevention in children.

Experimental Therapeutic Strategies in Epilepsies Using Anti-Seizure Medications

Epilepsies are among the most common neurological problems. The disease burden in patients with epilepsy is significantly high, and epilepsy has a huge negative impact on patients' quality of life with epilepsy and their families. Anti-seizure medications are the mainstay treatment in patients with epilepsy, and around 70% of patients will ultimately control with a combination of at least two appropriately selected anti-seizure medications. However, in one-third of patients, seizures are resistant to drugs, and other measures will be needed. The primary goal in using experimental therapeutic medication strategies in patients with epilepsy is to prevent recurrent seizures and reduce the rate of traumatic events that may occur during seizures. So far, various treatments using medications have been offered for patients with epilepsies, which have been classified according to the type of epilepsy, the effectiveness of the medications, and the adverse effects. Medications such as Levetiracetam, valproic acid, and lamotrigine are at the forefront of these patients' treatment. Epilepsy surgery, neuro-stimulation, and the ketogenic diet are the main measures in patients with medication-resistant epilepsies. In this paper, we will review the therapeutic approach using anti-seizure medications in patients with epilepsy. However, it should be noted that some of these patients still do not respond to existing treatments; therefore, the limited ability of current therapies has fueled research efforts for the development of novel treatment strategies. Thus, it seems that in addition to surgical measures, we should look for more specific agents that have less adverse events and have a greater effect in stopping seizures.

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.