Use of extended-release and immediate-release anti-seizure medications with a long half-life to improve adherence in epilepsy: A guide for clinicians

Madhuca indica oil-entrapped buoyant galactomannan hydrogel microspheres for controlling epileptic seizures

A stable Madhuca indica oil-in-water nanoemulsion (99-210 nm, zeta potential: > - 30 mV) was produced employing Tween 20 (surfactant) and Transcutol P (co-surfactant) (3:1). The nanoemulsion (oil: Smix = 3:7, 5:5, and 7:3) were subsequently incorporated into oxcarbazepine-loaded carboxymethylxanthan gum (DS = 1.23) dispersion. The hydrogel microspheres were formed using the ionic gelation process. Higher oil concentration had a considerable impact on particle size, drug entrapment efficiency, and buoyancy. The maximum 92 % drug entrapment efficiency was achieved with the microspheres having oil: Smix ratio 5:5. FESEM study revealed that the microspheres were spherical in shape and had an orange peel-like surface roughness. FTIR analysis revealed a hydrogen bonding interaction between drug and polymer. Thermal and x-ray examinations revealed the transformation of crystalline oxcarbazepine into an amorphous form. The microspheres had a buoyancy period of 7.5 h with corresponding release of around 83 % drug in 8 h in simulated stomach fluid, governed by supercase-II transport mechanism. In vivo neurobehavioral studies on PTZ-induced rats demonstrated that the microspheres outperformed drug suspension in terms of rotarod retention, number of crossings, and rearing activity in open field. Thus, Madhuca indica oil-in-water nanoemulsion-entrapped carboxymethyl xanthan gum microspheres appeared to be useful for monitoring oxcarbazepine release and managing epileptic seizures.

Lacosamide extended-release capsules are bioequivalent to lacosamide immediate-release tablets: Pharmacokinetic observations and simulations

OBJECTIVES

Assess the bioequivalence of lacosamide extended-release (XR) capsules and immediate-release (IR) tablets and answer real-world clinical questions regarding the use of lacosamide XR.

METHODS

An open-label, randomized, two-treatment, two-sequence, oral comparative bioavailability study was conducted to assess the bioequivalence of two lacosamide formulations. Participants were randomized 1:1 to receive lacosamide XR capsules (400 mg once-daily) or IR tablets (200 mg twice-daily) in 1 of 2 sequences over 7-day periods. Primary outcome was the area under the lacosamide concentration-time curve over 24 h at steady-state (AUC0-τ,ss). Secondary outcomes were maximum (Cmax,ss) and minimum concentrations at steady-state (Cmin,ss). Bioequivalence was established when 90% confidence intervals (CIs) for geometric least square means ratios (GLSMs) were between 80% and 125%. Adverse events (AEs) and other safety outcomes were also assessed. Pharmacokinetic simulations, including adherent and partially adherent dosing scenarios with XR and IR formulations, modeled the clinical use of lacosamide XR.

RESULTS

Thirty-five healthy adult males were enrolled in the bioequivalence study. After 7 days of study drug, mean AUC0-τ,ss, Cmax,ss, and Cmin,ss values were similar between XR and IR formulations; all 90% CIs for GLSMs were between 80% and 125%. AEs were mild and no serious AEs or other clinically significant safety findings were observed. Pharmacokinetic simulations suggested that partial adherence affected formulations similarly; and the best strategy for switching formulations was to take the morning lacosamide IR dose followed by the evening lacosamide XR dose, as this resulted in the most consistent lacosamide plasma concentrations.

CONCLUSIONS

Once-daily lacosamide XR capsules were bioequivalent to twice-daily lacosamide IR tablets. Pharmacokinetic simulations indicated lacosamide XR and IR formulations were similarly affected by partial adherence, though once-daily dosing with lacosamide XR may offer clinical advantages, and formulations can be easily switched. These results support the use of lacosamide XR capsules as a once-daily alternative to lacosamide IR tablets.

Intranasal delivery of phenytoin loaded layered double hydroxide nanoparticles improves therapeutic effect on epileptic seizures

Improving the efficiency of antiseizure medication entering the brain is the key to reducing its peripheral toxicity. A combination of intranasal administration and nanomedicine presents a practical approach for treating epileptic seizures via bypassing the blood-brain barrier. In this study, phenytoin (PHT) loaded layered double hydroxide nanoparticles (BSA-LDHs-PHT) were fabricated via a coprecipitation - hydrothermal method for epileptic seizure control. In this study, we expound on the preparation method and characterization of BSA-LDHs-PHT. In-vitro drug release experiment shows both rapid and continuous drug release from BSA-LDHs-PHT, which is crucial for acute seizure control and chronic epilepsy therapy. In-vivo biodistribution assays after intranasal administration indicate excellent brain targeting ability of BSA-LDHs. Compared to BSA-Cyanine5.5, BSA-LDHs-Cyanine5.5 were associated with a higher brain/peripheral ratio across all tested time points. Following intranasal delivery with small doses of BSA-LDHs-PHT, the latency of seizures in the pentylenetetrazole-induced mouse models was effectively improved. Collectively, the present study successfully designed and applied BSA-LDHs-PHT as a promising strategy for treating epileptic seizures with an enhanced therapeutic effect.

Sources of pharmacokinetic and pharmacodynamic variability and clinical pharmacology studies of antiseizure medications in the pediatric population

Multiple treatment options exist for children with epilepsy, including surgery, dietary therapies, neurostimulation, and antiseizure medications (ASMs). ASMs are the first line of therapy, and more than 30 ASMs have U.S. Food and Drug Administration (FDA) approval for the treatment of various epilepsy and seizure types in children. Given the extensive FDA approval of ASMs in children, it is crucial to consider how the physiological and developmental changes throughout childhood may impact drug disposition. Various sources of pharmacokinetic (PK) variability from different extrinsic and intrinsic factors such as patients' size, age, drug-drug interactions, and drug formulation could result in suboptimal dosing of ASMs. Barriers exist to conducting clinical pharmacological studies in neonates, infants, and children due to ethical and practical reasons, limiting available data to fully characterize these drugs' disposition and better elucidate sources of PK variability. Modeling and simulation offer ways to circumvent traditional and intensive clinical pharmacology methods to address gaps in epilepsy and seizure management in children. This review discusses various physiological and developmental changes that influence the PK and pharmacodynamic (PD) variability of ASMs in children, and several key ASMs will be discussed in detail. We will also review novel trial designs in younger pediatric populations, highlight the role of extrapolation of efficacy in epilepsy, and the use of physiologically based PK modeling as a tool to investigate sources of PK/PD variability in children. Finally, we will conclude with current challenges and future directions for optimizing the efficacy and safety of these drugs across the pediatric age spectrum.

Medication compliance of children with epilepsy: a cross-sectional survey

BACKGROUND

Good medication compliance is very important for the prognosis of children with epilepsy. We aimed to evaluate the status and influencing factors of medication compliance in children with epilepsy and to provide insights to the clinical nursing care of children with epilepsy.

METHODS

We selected epileptic children admitted to Children's Hospital of Nanjing Medical University from February 1, 2022 to August 31, 2022. Self-designed questionnaire and medication compliance scale were used to evaluate the characteristics and medication compliance of children with epilepsy. Pearson correlation analysis and multivariate logistic regression were used to analyze the influencing factors of medication compliance.

RESULTS

A total of 156 children with epilepsy were included, the incidence of poor compliance in children with epilepsy was 37.18%. Pearson correlation analysis indicated that age(r = 0.622), courses of epilepsy(r = 0.553), parental education level(r = 0.506), monthly household income(r = 0.652) and number of drugs taken(r = 0.577) were correlated with the compliance(all P<0.05). Logistic regression analyses indicated that age ≤ 6 y(OR = 2.104, 95%CI: 1.712 ~ 2.527), courses of epilepsy ≤ 3 years(OR = 2.661, 95%CI: 2.089 ~ 2.941), low parental education level(OR = 1.977, 95%CI: 1.314 ~ 2.351), monthly household income ≤ 5000 RMB(OR = 2.812, 95%CI: 2.194 ~ 3.181), number of drugs taken ≥ 3(OR = 3.025, 95%CI: 2.336 ~ 3.475) were the influencing factors of medication compliance in children with epilepsy(all P<0.05).

CONCLUSIONS

The medication compliance of children with epilepsy needs to be improved, and the medication compliance of children is affected by age, courses of epilepsy, parental education level, monthly household income and number of drugs taken. Clinical medical personnel take targeted nursing measures against these factors to improve the medication compliance of children with epilepsy.

Perampanel's forgiveness factor in a variable medication adherence paradigm in a rat model of chronic epilepsy

BACKGROUND

Poor medication adherence contributes to increased morbidity and mortality in patients with epilepsy and may be under-addressed in clinical practice. Ethical concerns make it impossible to study the impact of medication nonadherence in clinical trials, but our previous work emphasizes the importance of using preclinical approaches to address these questions. With over 30 clinically available antiseizure medicines (ASM's), it remains an important question to understand the relationship between poor adherence and seizure incidence across mechanistically distinct ASM's, including the broad-spectrum ASM, perampanel (PER).

METHODS

We formulated PER into chow pellets to deliver to rats in a 100% fully adherent or 50% variable nonadherent paradigm via our novel automated medication-in-food delivery system. Chronic oral dosing was initiated in male rats with chronic epilepsy while monitoring 24/7 for videoEEG evidence of seizures during a 4-week placebo baseline and 4-week treatment phase. PER concentrations were monitored in plasma at 1-week intervals and correlated with degree of seizure control. The relationship between missed doses and extended patterns of nonadherence were correlated with breakthrough seizures.

RESULTS

Fully adherent rats demonstrated a median reduction in seizure frequency of 50%, whereas nonadherent rats had a median increase of 54%. Plasma concentrations of PER were stable over the 4-week treatment period in both fully adherent and nonadherent groups, with levels being twice as high in fully adherent animals. There was no correlation between a single missed dose or series of missed doses and the incidence of breakthrough seizures. However, those animals in the nonadherent group that received PER for every meal during a 24-h period had a reduced likelihood of seizure incidence.

CONCLUSIONS

If our preclinical data is supported in the clinic, PER's favorable pharmacokinetic profile in humans, combined with a lowered risk of breakthrough seizures suggests that it may provide a certain forgiveness factor if a dose is missed within a 24-h window.

Safety evaluation of perampanel as monotherapy or first adjunctive therapy in patients with epilepsy

INTRODUCTION

There is a need for anti-seizure medications (ASMs) that are well tolerated and effective as monotherapy or first adjunctive therapy to reduce the need for adjunctive ASMs to treat newly diagnosed epilepsy, and to reduce the number of concomitant ASMs in patients with refractory epilepsy. Although the pivotal trials of perampanel evaluated its adjunctive use in patients with refractory seizures, open-label/real-world studies support its use in first/second-line settings.

AREAS COVERED

This paper reviews the pharmacology, efficacy, and safety/tolerability of perampanel, focusing on its use as monotherapy or first adjunctive therapy. The safety of perampanel in special populations and its safety/tolerability compared with that of other ASMs is also discussed.

EXPERT OPINION

Perampanel is a favorable candidate for initial or first adjunctive therapy due to its favorable efficacy and safety/tolerability as monotherapy and adjunctive therapy, its long half-life and ease of use, and its limited drug-drug interactions. The proposed mitigation strategies for managing the risk of serious psychiatric adverse events are appropriate patient selection, use of low doses, and slow titration. The growing body of evidence might shift current treatment strategies towards the early use of perampanel and its use at a low dose (4 mg/day).

Antiseizure Medications for Adults With Epilepsy: A Review

IMPORTANCE

Epilepsy affects approximately 65 million people worldwide. Persistent seizures are associated with a 20% to 40% risk of bodily injuries (eg, fractures, burns, concussions) over 12-month follow-up. The primary goal of epilepsy treatment is to eliminate seizures while minimizing adverse effects of antiseizure drugs (ASDs).

OBSERVATIONS

An epileptic seizure is defined as a sudden occurrence of transient signs and symptoms caused by abnormal and excessive or synchronous neuronal activity in the brain. Focal and generalized epilepsy are the 2 most frequent types of epilepsy; diagnosis is based on the type of seizures. There are 26 US Food and Drug Administration-approved medications for epilepsy, of which 24 have similar antiseizure efficacy for focal epilepsy and 9 have similar efficacy for generalized epilepsy. The decision to initiate an ASD should be individualized, but should be strongly considered after 2 unprovoked seizures or after 1 unprovoked seizure that occurred during sleep and/or in the presence of epileptiform activity on an electroencephalogram and/or in the presence of a structural lesion on the brain magnetic resonance imaging. The ASDs must be selected based on the seizure and epilepsy types, the epilepsy syndrome, and the adverse effects associated with the drug. For focal epilepsy, oxcarbazepine and lamotrigine are first-line therapy, while levetiracetam can be also considered if there is no history of psychiatric disorder. For generalized epilepsy, the selection of the ASD is based on the type of epilepsy syndrome and the patient's sex, age, and psychiatric history. Seizure freedom is achieved in approximately 60% to 70% of all patients. A total of 25% to 50% of patients also experience neurologic, psychiatric, cognitive, or medical disorders, such as mood, anxiety, and attention deficit disorders and migraines. For these patients, selecting an ASD should consider the presence of these disorders and concomitant use of medications to treat them. ASDs with cytochrome P450 enzyme-inducing properties (eg, carbamazepine, phenytoin) may worsen comorbid coronary and cerebrovascular disease by causing hyperlipidemia and accelerating the metabolism of concomitant drugs used for their treatment. They can also facilitate the development of osteopenia and osteoporosis.

CONCLUSIONS AND RELEVANCE

Epilepsy affects approximately 65 million people worldwide and is associated with increased rates of bodily injuries and mortality when not optimally treated. For focal and generalized epilepsy, selection of ASDs should consider the seizure and epilepsy types and epilepsy syndrome, as well as the patient's age and sex, comorbidities, and potential drug interactions.

Designing Drug Regimens that Mitigate Nonadherence

Medication adherence is a well-known problem for pharmaceutical treatment of chronic diseases. Understanding how nonadherence affects treatment efficacy is made difficult by the ethics of clinical trials that force patients to skip doses of the medication being tested, the unpredictable timing of missed doses by actual patients, and the many competing variables that can either mitigate or magnify the deleterious effects of nonadherence, such as pharmacokinetic absorption and elimination rates, dosing intervals, dose sizes, and adherence rates. In this paper, we formulate and analyze a mathematical model of the drug concentration in an imperfectly adherent patient. Our model takes the form of the standard single compartment pharmacokinetic model with first-order absorption and elimination, except that the patient takes medication only at a given proportion of the prescribed dosing times. Doses are missed randomly, and we use stochastic analysis to study the resulting random drug level in the body. We then use our mathematical results to propose principles for designing drug regimens that are robust to nonadherence. In particular, we quantify the resilience of extended release drugs to nonadherence, which is quite significant in some circumstances, and we show the benefit of taking a double dose following a missed dose if the drug absorption or elimination rate is slow compared to the dosing interval. We further use our results to compare some antiepileptic and antipsychotic drug regimens.

What should patients do if they miss a dose of medication? A theoretical approach

Medication adherence is a major problem for patients with chronic diseases that require long term pharmacotherapy. Many unanswered questions surround adherence, including how adherence rates translate into treatment efficacy and how missed doses of medication should be handled. To address these questions, we formulate and analyze a mathematical model of the drug concentration in a patient with imperfect adherence. We find exact formulas for drug concentration statistics, including the mean, the coefficient of variation, and the deviation from perfect adherence. We determine how adherence rates translate into drug concentrations, and how this depends on the drug half-life, the dosing interval, and how missed doses are handled. While clinical recommendations require extensive validation and should depend on drug and patient specifics, as a general principle our theory suggests that nonadherence is best mitigated by taking double doses following missed doses if the drug has a long half-life. This conclusion contradicts some existing recommendations that cite long drug half-lives as the reason to avoid a double dose after a missed dose. Furthermore, we show that a patient who takes double doses after missed doses can have at most only slightly more drug in their body than a perfectly adherent patient if the drug half-life is long. We also investigate other ways of handling missed doses, including taking an extra fractional dose following a missed dose. We discuss our results in the context of hypothyroid patients taking levothyroxine.