Antiepileptic drug treatment: new drugs and new strategies

Influence of Different Antiseizure Medications on Vascular Risk Factors in Children with Epilepsy

Many studies have proposed that plasma homocysteine levels are increased as a side effect with the prolonged use of antiseizure medications. This is associated with an increase in carotid intima media thickness; hence, it increases the threat of atherosclerosis at a young age. We aimed to assess serum levels of homocysteine in epileptic children on long-standing antiseizure medications and its association with increased occurrence of cardiovascular disease. The study included 60 epileptic children aged between 2 and 15 years old who visited our pediatric neurology outpatient clinic and 25 apparently healthy children served as a control group. All included children were subjected to careful history taking, clinical examination, anthropometric measures, laboratory investigations including serum homocysteine levels and lipid profile, along with radiological assessment involving carotid intima media thickness and carotid stiffness. Results demonstrated a significant increase in the serum levels of homocysteine, carotid intima media thickness, and carotid stiffness in children on monotherapy of old generation antiseizure medications and polytherapy than that in children on monotherapy of new generation antiseizure medications and control children. Epileptic children on old generation and polytherapy antiseizure medications have an increased risk for cardiovascular diseases and need follow up for early intervention when needed.

Cognitive, behavioural and sleep-related adverse effects on introduction of levetiracetam versus oxcarbazepine for epilepsy

OBJECTIVE

There is limited literature on cognitive, behaviour and sleep-related adverse effects of levetiracetam and oxcarbazepine among adult epilepsy patients, except for what is available from the initial efficacy trials. This study was initiated with the aim to evaluate the incidence and prevalence of various cognitive, behaviour and sleep-related adverse effects of levetiracetam versus oxcarbazepine among people with epilepsy.

METHODS

The study was conducted in two parts: part A was a cross-sectional study, and part B was a longitudinal study. Trail making test A & B, digit symbol substitution test, Stroop colour and word test, controlled oral word association test and PGI memory scale, Neuropsychiatric Inventory, sleep log and ESS-I were used for assessment of cognitive, behaviour and sleep-related adverse effects.

RESULTS

In the cross-sectional as well as prospective study, no significant difference was observed in the cognitive performance of patients in levetiracetam and oxcarbazepine group in any of the cognitive assessment. Among 120 patients enrolled in the cross-sectional study, significantly higher number of patients in the levetiracetam group compared to the oxcarbazepine group,had agitation/aggression (20% vs10%, p =  0.047) and irritability (26.7% vs 3.3%, p = 0.007).Among 132 patients enrolled in the prospective study, significantly higher increase in the domain score of agitation/aggression (14.5% vs 1.6%, p = 0.028) and irritability (17.7% vs 1.6%, p =  0.018) was observed in the levetiracetam group compared to oxcarbazepine group. A significantly higher proportion of patients in the oxcarbazepine group had hypersomnolence (11.3% vs 1.6%, p =  0.026), as compared to the levetiracetam group.

SIGNIFICANCE

On cross-sectional as well as on longitudinal assessment, nearly one-fifth of patients on levetiracetam have behaviour related adverse effects, with dose modification required for half among these. Nearly 11% of patients on oxcarbazepine reported sleep-related adverse effects (higher total sleep duration per 24 h).

Antiepileptic drug therapy in autoimmune epilepsy associated with antibodies targeting the leucine-rich glioma-inactivated protein 1

Objective

To characterize seizure semiology and the utility of antiepileptic drug (AED) therapy in leucine‐rich glioma inactivated‐1 ( LGI1‐Ab) autoimmune epilepsy (AE).

Methods

Patients with voltage‐gated potassium channel complex (VGKCc) titers higher than 0.02 nmol/L who were evaluated between May 2008 and June 2016 at the 3 Mayo Clinic sites (Arizona, Florida, or Minnesota) were identified. We then performed a retrospective review of those who were LGI1‐Ab positive and were treated for seizures.

Results

A total of 1,095 patients with VGKCc titers higher than 0.02 nmol/L were identified, in which 77 were LGI1 positive. Of these, 56 patients with seizures were included in the analysis. Mean age at symptom onset was 62.9 years; 66% (n = 37) were male. The most common seizure semiology was focal faciobrachial dystonic seizures with preserved awareness (FBDS) (n = 35, 63%), followed by focal with impaired awareness (FIA) (n = 29, 52%), generalized tonic–clonic (GTCs) (n = 28, 50%), and focal non‐motor seizures with preserved awareness (n = 28, 50%). The majority had more than one seizure type (n = 49, 88%; median = 2.5). Thirty‐eight patients (68%) became seizure free: 29 (76%) with immunotherapy, 3 (5%) with AEDs alone, 2 (3%) with AEDs before any immunotherapy, and 4 (7%) with AEDs after immunotherapy. Levetiracetam (n = 47, 84%) and valproic acid (n = 21, 38%) were the most commonly used AEDs, but neither were associated with seizure freedom. Sodium channel blocking (NCB) AEDs were associated with seizure freedom in 4 patients compared to none treated with non‐NCB AEDs. Regardless of class, AEDs prior to or apart from immunotherapy were associated with seizure freedom in only five patients (9%). In patients with FBDS, seizure freedom was more often associated with immunotherapy than AEDs (20/30 vs. 3/34, p = 0.001).

Significance

Although FBDS are the most characteristic seizure type seen in LGI1‐Ab AE, other seizure types including FIA and GTCs also occur. Immunotherapy was the treatment most frequently associated with seizure freedom in LGI1‐Ab AE. In general, AEDs seemed to confer a very low chance for seizure freedom, although AEDs with NCB‐blocking properties were associated with seizure freedom in a limited number. Levetiracetam in particular appears to be ineffective in this patient population.

[The clinical significance of the lamotrigine pharmacokinetic variability]

AIM

To estimate pharmacokinetic variability of lamotrigine (LTG) and its clinical significance.

MATERIAL AND METHODS

One hundred patients, including 74 women, aged from 18 to 77 years (38.23±14.37 years), with focal epilepsy were examined. Monotherapy with LTG was administered to 54 patients, duotherapy to 46 patients (LTG and valproic acid combination to 27 patients, LTG and liver enzymes inducers to 19 patients). Patients underwent procedures of therapeutic drug monitoring (TDM). Minimal (Css_min) and maximal (Css_max) steady-state LTG plasma concentrations, and concentration-to-weight ratio (CDR) were calculated.

RESULTS AND CONCLUSION

In patients who used LTG in monotherapy, LTG Css_min was 5.6±4.65 mg/l, Css_max 7.59±5.54 mg/l. In the group that received LTG in combination with valproate, LTG Сss_min was 7.8 [5.4; 11.8] mg / l and Css_max 11.4 [7.3; 15.3] mg/l. In the group that received LTG in combination with drug-inducers of glucuronidation, Css_min was 2.5 [1.99; 4.32] mg/l, Css_max 4.73 [2.91; 6.70] mg/l. Statistically significant differences in CDR parameter between groups with LTG monotherapy and duotherapy, both with inducer and with inhibitors, as well as between groups of duotherapy with inductors and with inhibitors were obtained. The results of the study indicate a pronounced pharmacokinetic variability of the LTG. Conducting TDM allows the establishment of individual therapeutic concentrations of LTG in blood plasma and setting a correction vector for antiepileptic therapy.

Antiepileptic drug therapy in patients with autoimmune epilepsy

Objective:

We aimed to report the pattern of usage and efficacy of antiepileptic drugs (AEDs) in patients with autoimmune epilepsy (AE).

Methods:

We retrospectively studied the Mayo Clinic's electronic medical record of patients with AE in which seizures were the main presenting feature. Clinical data, including demographics, seizure characteristics, type of AED and immunotherapy used, presence of neural antibody, and treatment outcomes, were reviewed.

Results:

The medical records of 252 adult patients diagnosed with autoimmune encephalitis and paraneoplastic disorders were reviewed. Seizure was the initial presentation in 50 patients (20%). Serum and/or CSF autoantibodies were detected in 41 (82%) patients, and 38 (76%) patients had neural autoantibodies. The majority (n = 43, 86%) received at least 1 form of immunotherapy in combination with AEDs, while the remainder received AEDs alone. Twenty-seven patients (54%) became seizure free: 18 (36%) with immunotherapy, 5 (10%) with AEDs alone, and 4 (8%) with AEDs after immunotherapy failure. Levetiracetam was the most commonly used (42/50); however, it was associated with 0% seizure-free response. AED seizure-free responses occurred with carbamazepine (n = 3) [3/16, 18.8%], lacosamide (n = 3) [3/18, 16.6%] with phenytoin (n = 1) [1/8, 12.5%], or oxcarbazepine (n = 2) [2/11, 18.1%]. Regardless of the type of therapy, voltage-gated potassium channel-complex antibody–positive patients were more likely to become seizure free compared with glutamic acid decarboxylase 65 antibody–positive cases (12/17 vs 2/10, p = 0.0183).

Conclusions:

In select patients, AEDs alone were effective in controlling seizures. AEDs with sodium channel blocking properties resulted in seizure freedom in a few cases. Prospective studies are needed to clarify AED selection and to elucidate their immunomodulatory properties in AE.

Future of seizure prediction and intervention: closing the loop

The ultimate goal of epilepsy therapies is to provide seizure control for all patients while eliminating side effects. Improved specificity of intervention through on-demand approaches may overcome many of the limitations of current intervention strategies. This article reviews the progress in seizure prediction and detection, potential new therapies to provide improved specificity, and devices to achieve these ends. Specifically, we discuss (1) potential signal modalities and algorithms for seizure detection and prediction, (2) closed-loop intervention approaches, and (3) hardware for implementing these algorithms and interventions. Seizure prediction and therapies maximize efficacy, whereas minimizing side effects through improved specificity may represent the future of epilepsy treatments.

Nonconvulsive seizure control in the intensive care unit

OPINION STATEMENT

Nonconvulsive seizures (NCS) occur in as many as 20 % of comatose critically ill patients. These seizures need to be treated; however, the urgency with which this must be done and the medications that should be used are unclear. Often, data from treatment of convulsive status epilepticus (SE) is used to determine the best therapy for NCS. This may lead to "overtreatment" with sedating medications that prolongs hospitalization and worsens outcome. Nonsedating antiepileptic drug (AED) use is favored by many neurologists as the side effect profile is superior to sedating medications. Though limited, the available data suggests that valproic acid and lacosamide may be preferable to phenytoin/fosphenytoin and levetiracetam based on efficacy and side effect profiles. Other AEDs such as topiramate and pregabalin have also been used, but their data is even more limited, and they do not have an intravenous formulation. Clinical trials that have recently been completed and those that are ongoing will further inform our decisions about which drugs to use in the future.

Pharmacokinetic of antiepileptic drugs in patients with hepatic or renal impairment

Many factors influence choice of antiepileptic drugs (AEDs), including efficacy of the drug for the indication (epilepsy, neuropathic pain, affective disorder, migraine), tolerability, and toxicity. The first-generation AEDs and some newer AEDs are predominately eliminated by hepatic metabolism. Other recent AEDs are eliminated by renal excretion of unchanged drug or a combination of hepatic metabolism and renal excretion. The effect of renal and hepatic disease on the dosing will depend on the fraction of the AED eliminated by hepatic and/or renal excretion, the metabolic isozymes involved, as well as the extent of protein binding, if therapeutic drug monitoring is used. For drugs that are eliminated by renal excretion, methods of estimating creatinine clearance can be used to determine dose adjustments. For drugs eliminated by hepatic metabolism, there are no specific markers of liver function that can be used to provide guidance in dosage adjustments. Based on studies with probe drugs, the hepatic metabolic enzymes are differentially affected depending on the cause and severity of hepatic disease, which can aid in predicting dose adjustment when clinical data are not available. Several AEDs are also associated with laboratory markers of mild hepatic dysfunction and, rarely, more severe hepatic injury. In contrast, the risk of renal injury from AEDs is generally low. In general, co-morbid hepatic or renal diseases influence the decision for the selection of an AED. For some patients dosing changes to their existing AEDs may be appropriate. For others, a change to another AED may be a better option.