Compliance and satisfaction with switching from an immediate-release to sustained-release formulation of valproate in people with epilepsy

Temporal relationship between levetiracetam nonadherence and breakthrough seizures in a preclinical model of temporal lobe epilepsy

OBJECTIVE

Poor medication adherence remains a concern for individuals managing their epilepsy with antiseizure medicines (ASMs); however, ethical concerns around withholding medication make it impossible to study the causal relationship between missed doses and seizures in patients. Previous preclinical studies from our group suggest that mechanistically distinct ASMs have varying degrees of forgiveness when a dose is missed. However, with only a few ASMs studied in the context of nonadherence, we sought to expand on previous work to understand the relationship between levetiracetam (LEV) nonadherence and breakthrough seizures.

METHODS

Chronic oral dosing was initiated in rats with established epilepsy via our automated medication-in-food delivery system coupled to 24/7 video-electroencephalographic recording. Baseline seizure burden was established for 4 weeks before enrolling subjects into a 4-week treatment period with LEV in a 100% fully adherent (75 mg/kg four times daily) or 50% variably adherent paradigm. The temporal relationship between missed doses and breakthrough seizures was correlated with LEV plasma and brain concentrations in separate cohorts of animals.

RESULTS

Full adherence to LEV significantly improved seizure control by 50% in half of the animals. Poor adherence worsened seizure frequency by 85%, with most rats having more severe seizures that formed in clusters following missed doses. LEV concentrations remained below therapeutic levels (<10 μg/mL) in nonadherent animals, with brain and plasma levels directly correlating with the degree of adherence in a 24-h period. Missed doses of LEV immediately increased the risk of breakthrough seizures; however, this risk was significantly reduced with improved adherence in a 24-h period.

SIGNIFICANCE

These findings enhance our understanding of ASM nonadherence in preclinical models, highlighting that the timing of missed doses and their impact on seizures may vary between different ASMs. Notably, LEV demonstrates a robust pharmacokinetic reliance on missed doses leading to breakthrough seizures.

On epilepsy perception: Unravelling gaps and issues

Epilepsy is one of the most common neurological diseases, but it can sometimes be under-reported or have a time delay in diagnosis. This data is not surprising if we consider that a person often seeks medical attention only after presenting a generalized tonic-clonic seizure. Epilepsy diagnostic delay is caused by several factors: under-reporting by patients, under-diagnosed epileptic manifestations by inexperienced clinicians, and lack of time in the emergency setting. The consequences of this delay are increased accidents, a high rate of premature mortality, and economic expanses for the healthcare system. Moreover, people with epilepsy have a higher probability of comorbidities than the general population, such as mood disorders or cognitive problems. Along with recurrent seizures, these comorbid diseases promote isolation and stigmatization of people with epilepsy, who suffer from discrimination at school, in the workplace, and even in social relationships. Public awareness of epilepsy and its comorbidities is necessary to prevent diagnostic delays and overcome social and professional iniquities for people with epilepsy.

Advances in biomaterials for the treatment of retinoblastoma

Retinoblastoma is the most common primary intraocular malignancy in children. Although traditional chemotherapy has shown some success in retinoblastoma management, there are several shortcomings to this approach, including inadequate pharmacokinetic parameters, multidrug resistance, low therapeutic efficiency, nonspecific targeting, and the need for adjuvant therapy, among others. The revolutionary developments in biomaterials for drug delivery have enabled breakthroughs in cancer management. Today, biomaterials are playing a crucial role in developing more efficacious retinoblastoma treatments. The key goal in the evolution of drug delivery biomaterials for retinoblastoma therapy is to resolve delivery-associated obstacles and lower nonlocal exposure while ameliorating certain adverse effects. In this review, we will first delve into the historical perspective of retinoblastoma with a focus on the classical treatments currently used in clinics to enhance patients' quality of life and survival rate. As we move along, we will discuss biomaterials for drug delivery applications. Various aspects of biomaterials for drug delivery will be dissected, including their features and recent advances. In accordance with the current advances in biomaterials, we will deliver a synopsis on the novel chemotherapeutic drug delivery strategies and evaluate these approaches to gain new insights into retinoblastoma treatment.

Detecting Reasons for Nonadherence to Medication in Adults with Epilepsy: A Review of Self-Report Measures and Key Predictors

This review presents individual reasons for self-reported nonadherence in people with epilepsy (PWE). A literature search was performed on the PubMed/Medline and Scopus databases for studies published up to March 2022. Thirty-six studies were included using the following inclusion criteria: original studies on adults with epilepsy, use of subjective self-report adherence measurement methods, and publication in English. Data were extracted using a standardized data extraction table, including the year of publication, authors, cohort size, study design, adherence measurement method, and self-reported reasons for nonadherence. Self-reported reasons for nonadherence were grouped following the WHO model with the five dimensions of nonadherence. In addition, study characteristics and sociodemographic information are reported. Of the 36 included studies, 81% were observational. The average nonadherence rate was nearly 50%. Across all studies, patient-associated, therapy-associated, and circumstance-related factors were the most frequently reported dimensions of nonadherence. These factors include forgetfulness, presence of side-effects, and history of seizures. Regarding healthcare system factors, financial problems were the most reported reason for nonadherence. Stigmatization and quality of life were the most frequently cited factors influencing nonadherence in the disease- and circumstance-related dimensions. The results suggest that interventions for improving adherence should incorporate all dimensions of nonadherence.

Age and sex determine conversion from immediate-release to extended-release tacrolimus in a multi-center cohort of Canadian pediatric renal transplant recipients

ER-Tac, taken once per day, is associated with improved adherence. This study examined the potential patient and clinical factors that influence clinicians to convert pediatric patients from immediate-release to ER-Tac. This prospective multi-center observational study followed Canadian pediatric kidney transplant recipients up to 5 years post-transplant. Cox Proportional Hazards Regression was used to examine the influence of factors on conversion to ER-Tac. Sixty-six participants were included in this analysis. For every additional year of age at the time of transplant, the likelihood of conversion was more than doubled (HR 2.54, CI 1.83, 3.54, P < 0.001). The impact of age reduced by three percent for every month after transplant (HR 0.97, CI 0.95, 0.98, P < 0.001). Girls were more likely to be converted than boys (HR 3.78, CI 1.35, 10.6, P 0.01). Adherence measures (MAM-MM and tacrolimus trough variability), individual barriers to adherence, renal function, HLA mismatch, and rejection were not significant predictors of conversion in the final regression model. ER-Tac was preferentially prescribed to older age and female patients. Female sex and adolescence are both associated with worse graft outcomes, but we found no link between individualized markers of adherence/graft risk and conversion. Clinicians appeared to be using demographic features to distinguish patients at perceived higher risk and converted accordingly, without a case-by-case evaluation of who is more susceptible to poor outcomes.

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

Poor adherence to anti-seizure medications (ASMs) is associated with breakthrough seizures and potentially increased toxicity in patients with epilepsy. Extended-release (ER) drugs and immediate-release (IR) drugs with a long half-life (t_1/2) that permit once-daily dosing (such as, perampanel, zonisamide, lamotrigine [IR, ER] and topiramate [ER]) have a number of advantages over short t_1/2 ASMs that require multiple daily dosing. These advantages include simplification of dosing regimens, reduction in pill burden, and a decrease in the peak-to-trough fluctuations in serum drug concentration that may be associated with a decreased risk of adverse effects and seizures. Such properties have wider implications in improving patient adherence to treatment. This article is intended as a practical guide for clinicians that provides an overview of the features of ER ASMs and long t_1/2 IR ASMs that are advantageous in the context of patient adherence and pharmacokinetic "forgiveness" (after missing a dose). In addition, we note that efforts to improve adherence should not depend solely on drug dosing regimens and drug pharmacokinetics, but should be part of a wider strategy that includes therapeutic drug monitoring, improved healthcare provider-patient dialogue, patient education, and the use of "reminder" technology.

Switching antiepileptic drugs to once-daily dosing regimens in epilepsy patients

BACKGROUND

Antiepileptic drug (AED) non-adherence is an important factor contributing to poor seizure control in patients with epilepsy.

AIM

The aim of this study is to investigate seizure improvement after switching AEDs to once-daily dosing regimens in patients with drug-resistant epilepsy related to AED non-adherence.

METHODS

We performed a 10-year retrospective analysis of drug-resistant epilepsy patients whom AED non-adherence attributed to drug resistance and switched AEDs to once-daily dosing regimens. Successful switching was defined by at least 70% reduction in seizure frequency without troublesome adverse events.

RESULTS

Among 401 patients with drug-resistant epilepsy, 88 patients with AED non-adherence were switched to once-daily dosing regimens. Forty-six patients (52.3%) experienced successful seizure control following the switch. A higher chance of successful switch was found in patients without MRI abnormality (16/46 vs. 24/42; P = .04) and in patients who were switched to extended-release formulations or different AEDs with longer half-lives (33/46 vs. 19/42; P = .02).

CONCLUSIONS

Our study shows that switching AEDs to once-daily dosing regimens was an effective therapeutic option in patients with poor seizure control related to AED non-adherence. Treatment with extended-release formulations or drugs with longer half-lives should be considered in these patients.

Epilepsy Treatment Outcome and Its Predictors among Ambulatory Patients with Epilepsy at Mizan-Tepi University Teaching Hospital, Southwest Ethiopia

Background

Epilepsy is among the most common neurological disorders which is highly treatable with currently available antiepileptic drugs at a reasonable price. In Ethiopia, despite a number of studies revealed high prevalence of epilepsy, little is known on predictors of poorly controlled seizures. Thus, the aim of this study was to assess epilepsy treatment outcome and its predictors among patients with epilepsy on follow-up at the ambulatory care unit of Mizan-Tepi University Teaching Hospital, Southwest Ethiopia.

Methods

A hospital-based cross-sectional study involving patient interview and chart review was conducted from March 10 to April 10, 2018. Drug use patterns and sociodemographic data of the study participants were accustomed to descriptive statistics. Backward logistic regression analysis was done to identify predictors of poor seizure control. Statistical significance was considered at p value <0.05.

Results

From a total of 143 studied patients with epilepsy, 60.8% had uncontrolled seizures. Monotherapy (79%) was commonly used for the treatment of seizures, of which phenobarbital was the most commonly utilized single anticonvulsant drug (62.9%). The majority (72.7%) of the patients had developed one or more antiepileptic-related adverse effects. Medium medication adherence (adjusted odds ratio (AOR) = 5.4; 95% CI = 1.52–19.23; p=0.009), poor medication adherence (AOR = 8.16; 95% CI = 3.04–21.90; p=0.001), head injury before seizure occurrence (AOR = 4.9; 95% CI = 1.25–19.27; p=0.02), and seizure attacks ≥4 episodes/week before AEDs initiation (AOR = 8.52; % CI = 2.41–13.45; p=0.001) were the predictors of uncontrolled seizure.

Conclusions

Based on our findings, more than half of the patients with epilepsy had poorly controlled seizures. Nonadherence to antiepileptic drugs, high frequency of seizure attack before AEDs initiation, and history of a head injury before the occurrence of seizure were predictors of uncontrolled seizure. Patient medication adherence should be increased by the free access of antiepileptic drugs and attention should be given for the patients with a history of head injury and high frequency of seizure attacks before AEDs initiation.

Medication Belief and Adherence among Patients with Epilepsy

BACKGROUND

Medication adherence and belief are crucial to achieving the desired goal of therapy in epileptic patients. However, there is a lack of study regarding medication adherence and belief in our setting. Therefore, the purpose of this study was to investigate medication adherence and belief and associated factors among ambulatory patients with epilepsy.

METHOD

A cross-sectional study was conducted on randomly selected epileptic patients at the neurologic clinic of Ayder Comprehensive Specialized Hospital, Ethiopia. Medication adherence and belief were assessed using self-reported questionnaires which were developed based on the review of different literatures. Data were analyzed using binary logistic regression analysis.

RESULT

We included a total of 292 patients. Almost two-thirds (65.4%) of the patients were nonadherent to their medications. The most common cause of nonadherence was forgetfulness (48.7%) followed by inability to get medicine (28.8) and safety concern (23.5%). The majority (78.4%) of the patients had high medication necessity belief while 44.1% had high concern belief about the potential adverse effect of their medications. Overall, 39.4% of the patients had a negative belief toward their medications. Comorbidity (AOR: 3.51, 95% CI: 1.20-10.31), seizure encounter within the last 3 months (AOR: 5.45, 95% CI: 2.48-12.00), low medication necessity belief (AOR: 3.38, 95% CI: 1.14-10.00), high medication concern belief (AOR: 4.23, 95% CI: 2.07-8.63), and negative medication belief (AOR: 4.17, 95% CI: 1.74-10.02) were predictors of medication nonadherence.

CONCLUSION

Majority of the epileptic patients were nonadherent to their medications, and more than one-third of the patients had a negative medication belief. Low medication necessity belief, high medication concern belief, negative medication belief, comorbidity, and seizure encounter were predictors of medication nonadherence. Therefore, healthcare providers should design educational programs to enhance the patients' believe about their medication in order to improve medication adherence and overall treatment outcome.

The clinical characteristics and related factors of tremor in patients with epilepsy

PURPOSE

Tremor is frequently observed in patients with epilepsy (PWE), which is generally attributed to the side-effect of antiepileptic drugs (AEDs) particularly valproate (VPA) with largely unknown mechanisms. The study aimed to assess the clinical features and related factors of tremor in PWE with tremor.

METHODS

PWE with tremor and a control group of age- and sex-matched PWE without tremor were enrolled. Detailed demographic and clinical information for each individual was recorded. PWE with tremor were evaluated by The Clinical Rating Scale for Tremor (CRST) and Tremor Related Activities of Daily Living (TRADL) questionnaire.

RESULTS

132 individuals were enrolled, which including sixty-six (36 males) PWE with tremor with mean age of 33 years and epilepsy duration of 12.5 years. Tremor was postural in all, with median duration of four and one year from diagnosis and AED treatment to the onset of tremor respectively. The upper limbs were predominantly affected. VPA had been used in 62 (93.9%) PWE with tremor compared to 31 (47.0%) PWE without tremor (P < 0.001). The total CRST score was significantly associated with epilepsy duration and maximum VPA dosage (B = 0.30, p < 0.001; B = 0.32, p = 0.013). Patients with VPA dosage over 17.05 mg/kg/d might be more vulnerable to develop tremor.

CONCLUSIONS

PWE with tremor were more frequently treated with VPA, however, tremor was mild in most without any functional impairment. Epilepsy duration and maximum VPA dosage were important factors of tremor severity, suggesting mechanisms underlying tremor in PWE may be an elaborate interplay of AEDs and disease itself.

A Clinician's Guide to Oral Extended-Release Drug Delivery Systems in Epilepsy

Epilepsy is one of the most common chronic neurologic disorders that affects individuals of all ages. It is primarily managed with antiepileptic drugs (AEDs), with the goal of maintaining complete seizure control combined with minimal or no adverse effects. Oral administration is the mainstay of AED delivery for patients with chronic epilepsy and consists essentially of immediate-release (IR) and modified-release (delayed-release and extended-release [ER]) dosage formulations. Extended-release formulations (hydrophilic or hydrophobic matrix systems, reservoir systems, and osmotic-release systems) release a drug in a controlled manner during an extended period of time following administration. Extended-release formulations have many advantages compared with IR formulations, including simplification of dosing regimens, reduction in pill burden, and reduction in the peak-to-trough fluctuations in serum drug concentration that may be associated with a decreased risk of adverse effects and of seizures. These advantages have the potential to increase adherence to antiepileptic therapy, improve the quality of life of patients, and reduce health care costs. This article, which is intended as a practical guide for clinicians, reviews the properties of the different ER AED formulations currently available and discusses the advantages of ER over IR formulations. Subsequently, an explanation of the technologic basis of the different oral ER formulations, the critical attributes that differentiate ER products, and their individual strengths and weaknesses is provided. Specific recommendations to practitioners on treating patients with ER formulations are included.

Antiepileptic drug treatment of generalized tonic-clonic seizures: An evaluation of regulatory data and five criteria for drug selection

BACKGROUND

A generalized tonic-clonic seizure (GTCS) is the most severe form of common epileptic seizure and carries the greatest risk of harm. The aim of this review is to provide an evidence-based guide for the selection of antiepileptic drugs (AEDs) for patients with GTCSs. Eight AEDs are approved in Europe and the USA for the treatment of both primarily GTCSs (PGTCSs) and secondarily GTCSs (SGTCSs) and are considered in this paper.

METHODS

Each AED is evaluated using five criteria: (1) efficacy, by seizure type (a: PGTCSs and b: SGTCSs); (2) adverse effects; (3) interactions; (4) adherence and dosing; and (5) mechanism of action (MOA). To ensure the inclusions of robust data, only efficacy data accepted by regulatory authorities were considered, and data related to adverse effects, interactions, adherence, and MOA were all extracted from UK Summaries of Product Characteristics (SPCs).

RESULTS

(1a) There is class 1 evidence of the efficacy of only four AEDs in controlling PGTCSs (lamotrigine, levetiracetam, perampanel, and topiramate). (1b) There is no class 1 evidence of the efficacy of any AED in SGTCSs although some evidence from pooled/subgroup analyses or meta-analyses supports the use of the four AEDs (levetiracetam, perampanel, topiramate, and with less robust data for lamotrigine). (2) AEDs are associated with different, but to some extent overlapping, common adverse effect profiles but have differing idiosyncratic adverse effects. (3) Pharmacokinetic interactions are seen with most, but not all, AEDs and are most common with carbamazepine and phenytoin. (4) Good adherence is important for seizure control and is influenced by frequency of dosing, among other factors. (5) Mechanism of action is also a consideration in rationalising AED selection when switching or combining AEDs.

CONCLUSION

Ultimately, the choice of AED depends on all these factors but particularly on efficacy and adverse effects. Different patients will weigh the various factors differently, and the role of the treating physician is to provide accurate information to allow patients to make informed choices.

Patients' perspectives on management and barriers of regular antiepileptic drug intake

PURPOSE

The aim of our study was to assess the management of drug intake and potential barriers to adherence reported by two different patient groups.

METHODS

The study was performed in cooperation with the Regional Chamber of Pharmacists of Rhineland-Palatinate and three neurologists in private practice specialized in epileptology. In total, 108 patients surveyed in 43 pharmacies (Group P) and 118 patients treated by the specialized neurologists (Group N) completed anonymously a questionnaire on intake of antiepileptic drugs (AEDs). The statistical evaluation was performed using nonparametric tests and logistic regression analyses.

RESULTS

Group N more often used adherence aids, compared with Group P (68.6% vs. 46.3%, p<0.01), and the number of doses per day was significantly lower in Group N (Mann-Whitney test, p=0.046), but the percentage of patients who reported problems with the regular intake of their medication did not differ significantly between groups (Group N vs. P: 47.0% vs. 40.0%). If patients noticed that they missed a dose, 45.3% completely skipped the missed dose (Group N vs. P: 43.0% vs. 48.1%, n.s.). In a multivariate analysis, significant risk factors of problems with regular drug intake were age<25yrs. (p<0.01) and patient-reported adverse effect of AED (p<0.01), followed by the number of AED doses per day (p<0.05), while gender, intake habits, usage of adherence aids, and patient-rated efficacy of AEDs were not significant.

CONCLUSION

Patients treated by neurologists specialized in epileptology did not report less problems with adherence than patients surveyed in pharmacies. Since barriers for a regular intake are diverse, the use of a short questionnaire on management of drug intake may lead to an individually tailored counseling of patients to improve adherence.

A review of medication adherence in people with epilepsy

People with epilepsy (PWE) have a higher risk of mortality in comparison with the general population. This in part reflects intrinsic factors or associated comorbidities, but poor adherence to anti-epileptic drugs (AED) has also been shown to contribute to increased risk of death and increased utilization of unscheduled care. The aim of this review was to determine the prevalence of non-adherence to AED in PWE, evaluate whether specific clinical and demographic features can allow clinicians to identify those at highest risk and identify the methods and techniques that can be used to improve adherence in clinical settings. We identified relevant studies for the prevalence of medication non-adherence in PWE by searching MEDLINE (1946-7 Dec 2015), EMBASE (1947-7 Dec 2015) and Cochrane Library (1946-7 Dec 2015) as per predefined inclusion and exclusion criteria. We included 17 research studies from our review of the medical literature to determine the prevalence of medication non-adherence in epilepsy. The prevalence of significant medication non-adherence in epilepsy has been reported to vary between 26% and 79%. This variation partly reflects the differences in defining what clinically significant medication adherence is, the methods used to estimate the scale of the problem and the underlying population heterogeneity. A number of clinical and demographic features have been associated with poor adherence allowing clinicians to identify those at greatest risk. Educating patients and their carers about the risks associated with poor adherence, certain behavioural interventions and simplifying their drug regimens have been shown to improve adherence.

Identifying the barriers to antiepileptic drug adherence among adults with epilepsy

PURPOSE

To identify the barriers to antiepileptic drug (AED) adherence among adults with epilepsy (AWE). The impact of AED non-adherence on quality of life (QoL) was also examined.

METHOD

Systematic design (SR) study. A search strategy was undertaken with no time limits, for articles published in English, in MEDLINE, CINANL, PsycINFO, EMBASE, Cochrane databases and grey literature sources. Eligibility criteria included participants with epilepsy over 18 years, who were prescribed AEDs. Adherence had to be defined and adherence assessment measurements identified. A screening process was undertaken to select eligible studies. Eight studies met the inclusion criteria and were included in a quantitative synthesis. Quality of evidence was conducted using the EBL critical appraisal checklist and assessing risk of bias within individual studies.

RESULTS

Across the included studies a high prevalence of non-adherence was identified. AED non-adherence was associated with specific beliefs about medications, being depressed or anxious, poor medication self-administration management, uncontrolled recent seizures, frequent medication dosage times, poor physician-patient relationship and perceived social support. Additionally, AED non-adherence impacted negatively on QoL as a result of poor seizure control.

CONCLUSION

Although included studies were of good quality, risk of biases reduced the generalisability of results. Findings suggested that comprehensive adherence assessments should routinely be performed. Recommendations for future research include the use of longitudinal research designs and a follow up SR to include the 16-18-year-old population.

Comparative Absorption Profiles of Divalproex Sodium Delayed-Release Versus Extended-Release Tablets—Clinical Implications

Background:

The distinct absorption characteristics of the conventional enteric-coated, delayed-release (DR) and the novel extended-release (ER) divalproex sodium formulations are not well recognized.

Objective:

To quantitatively and qualitatively differentiate the absorption characteristics of divalproex-DR and -ER formulations.

Methods:

Healthy volunteers (N = 28) received single 1000 mg doses of divalproex-DR and divalproex-ER tablets in a crossover fashion. Noncompartmental and compartmental analyses were used to estimate valproic acid (VPA) pharmacokinetics from the plasma concentration–time profiles determined from intensive blood sampling over 48 hours.

Results:

VPA was not absorbed from divalproex-DR in the first 2 hours (absorption lag-time) after dosing. After VPA release in the intestine, approximately 63% of the dose was absorbed in less than 1 hour, that is, 2.9 hours (mean absorption time) from dosing. Maximum concentration (Cmax) was achieved approximately 4 hours after dosing. VPA absorption was complete (~93% of dose) within 3 absorption half-lives (~4.5 h) post-absorption lag-time, that is, 6–7 hours from dosing. In contrast, VPA absorption from divalproex-ER starts immediately after administration, initially at a modest rate, followed by slow and extended absorption at a constant rate for more than 20 hours; VPA concentrations at 1 and 2 hours were 28% and 40% of Cmax. Approximately 53% of the dose was absorbed within 12 hours (mean absorption time); complete absorption occurred over more than 20 hours without any dose dumping.

Conclusions:

When antihypertensive treatment options are clinically equivalent, prescribers may first consider using a verapamil SR–based strategy, especially in patients with CAD who have no history of depression. VPA absorption from enteric-coated divalproex-DR is rapid following a lag-time of approximately 2 hours and is complete within 6–7 hours of dosing. In contrast, VPA absorption from divalproex-ER starts immediately after administration, but occurs at a slow, approximately constant rate over more than 20 hours.

Effect of solvent on retarding the release of diltiazem HCl from Polyox-based liquisolid tablets

Objectives

The aim of this work was to investigate the use of liquisolid technique to sustain the release of a model highly soluble drug, diltiazem HCl, from liquisolid matrices containing Polyox, a recently proposed matrix-forming hydrophilic polymer as an alternative to hypromellose.

Methods

Polyox-based liquisolid formulations prepared using several non-volatile solvents (i.e. polysorbate 80, polyethylene glycol, polyethylene glycol 200 and polyethylene glycol 600) and then characterised using differential scanning calorimetry and powder X-ray diffraction. The influence of solvent on retarding the release of diltiazem HCl from Polyox-based liquisolid tablets compared to conventional physical mixture tablets was studied.

Key findings

Liquisolid tablets exhibited greater retarding properties compared to conventional tablets. The use of polysorbate produced a slower release pattern of the drug from diltiazem hydrochloride (DTZ) liquisolid tablets compared to propylene glycol and polyethylene glycol (200 and 600). The release retardation was decreased with the increase in the concentration of the drug within drug:solvent liquid medication used. Solid-state analysis suggested the presence of a fraction of the drug mass in a solubilised state within polysorbate in liquisolid powders.

Conclusion

Polyox-based matrix tablets prepared using liquisolid technique in the presence of a carefully selected non-volatile solvent could produce desirable, more sustained release profiles of highly water-soluble drugs compared to conventional physical mixture tablets.

Evaluation of self-reported medication adherence and its associated factors among epilepsy patients in Hospital Kuala Lumpur

INTRODUCTION

Reports on medication adherence and its associated factors in patients with epilepsy in South East Asian countries are lacking. The primary purpose of this study was to assess the degree of medication adherence and its relationship with patient's satisfaction, psychosocial factors, quality of life and mental health in a sample of Malaysian epilepsy patients.

METHODOLOGY

It is a cross-sectional study and was carried out in the outpatient Neurology Department of Hospital Kuala Lumpur, Malaysia (n=272). Data was collected by administering the structured questionnaire.

RESULTS AND DISCUSSION

Results showed that 49.3% of the epilepsy patients were non-adherent to their prescribed regimen. Univariate analysis showed significant associations between medication adherence and the following factors: race, seizure frequency, overall patient satisfaction, medication taste and smell, medication cost and physical appearance, medication effectiveness, complexity of medication regimen, patient barrier, patient understanding, patient role functioning, patient positivity, vitality and general interest. Multiple regression analysis indicated that factors that are influencing medication adherence are seizure frequency (P = 0.048), overall patient satisfaction (P = 0.043) and patient understanding about their illness (P = 0.001). The model chosen for testing the relationship between medication adherence and its associated factors give an R2 value of 25.2% with an adjusted R2 of 21.4%. The F value was also significant (P = 0.000). Based on the research findings, the researchers recommends that clinicians need to play a vital role in educating the patients on their disease conditions. By educating the patients on nature of epilepsy, different modalities of treatment and benefits of adherence to treatment will help in the better adherence and management.

Patient perceptions of physician-documented quality care in epilepsy

OBJECTIVE

The aim of this study was to compare physician encounter documentation with patient perceptions of quality of epilepsy care and examine the association between quality and patient assessment of provider communication.

METHODS

We identified 505 adult patients with epilepsy aged 18years or older over a 3-year period in two large academic medical centers. We abstracted individual, clinical, and care measures from 2723 electronic clinical notes written by physicians. We then randomly selected 245 patients for a phone interview. We compared patient perceptions of care with the documented care for several established epilepsy quality measures. We also explored the association of patient's perception of provider communication with provider documentation of key encounter interventions.

RESULTS

There were 88 patients (36%) who completed the interviews. Fifty-seven (24%) refused to participate, and 100 (40%) could not be contacted. Participants and nonparticipants were comparable in their demographic and clinical characteristics; however, participants were more often seen by epilepsy specialists than nonparticipants (75% vs. 61.9%, p<0.01). Quality scores based on patient perceptions differed from those determined by assessing the documentation in the medical record for several quality measures, e.g., documentation of side effects of antiseizure therapy (p=0.05), safety counseling (p<0.01), and counseling for women of childbearing potential with epilepsy (McNemar's p=0.03; intraclass correlation coefficient, ICC=0.07). There was a significant, positive association between patient-reported counseling during the encounter (e.g., personalized safety counseling) and patient-reported scores of provider communication (p=0.05).

CONCLUSIONS

The association between the patient's recollection of counseling during the visit and his/her positive perception of the provider's communication skills highlights the importance of spending time counseling patients about their epilepsy and not just determining if seizures are controlled.

Factors associated with treatment non-adherence in patients with epilepsy in Brazil

PURPOSE

To investigate factors associated with treatment non-adherence in Brazilian patients with epilepsy.

METHODS

Prospective cross-sectional study. We evaluated 385 epilepsy outpatients in a tertiary referral center, 18 years or older, literate, without cognitive impairment or active psychiatric disorders, who were independent in daily living activities. Data were analyzed with correlation tests and conjoint analysis using multivariate logistic regression.

RESULTS

Non-adherence rate, measured by the Morisky-Green Test, was 66.2%, a moderate-to-low adherence level. Non-adherence was higher in men, in younger patients and in patients with uncontrolled seizures. Increasing treatment complexity was also associated with decreased treatment adherence.

CONCLUSION

Strategies designed to improve treatment adherence should address peculiarities associated with younger ages and male gender. Physicians should be made aware that prescription of less complex treatment regimens may result in better treatment adherence, and, therefore, better seizure control. The challenge in adjusting AED treatment in this population is to minimize treatment complexity, thus increasing chances for treatment adherence.

Dosing frequency and adherence in chronic psychiatric disease: systematic review and meta-analysis

BACKGROUND

The purpose of this study was to investigate the impact of dosing frequency on adherence in severe chronic psychiatric and neurological diseases.

METHODS

A systematic literature review was conducted for articles in English from medical databases. Diseases were schizophrenia, psychosis, epilepsy, bipolar disorder, and major depressive disorder.

RESULTS

Of 1420 abstracts screened, 12 studies were included. Adherence measures included Medication Event Monitoring System (MEMS(®)), medication possession ratio, medication persistence, and refill adherence. Three schizophrenia and one epilepsy study used MEMS, and all showed a trend towards higher adherence rates with less frequent dosing regimens. Three depression and one schizophrenia study used the medication possession ratio; the pooled odds ratio of being adherent was 89% higher (ie, 1.89, 95% credibility limits 1.71-2.09) on once-daily versus twice-daily dosing. Two studies in depression and one in all bupropion patients assessed medication persistence and refill adherence. The pooled odds ratio for the two depression studies using medication persistence was 2.10 (95% credibility limits 1.86-2.37) for once-daily versus twice-daily dosing. For refill adherence after 9 months, 65%-75% of patients on once-daily versus 56% on twice-daily dosing had at least one refill. In all but one of the studies using other measures of adherence, adherence rates were higher with once-daily dosing compared with more frequent dosing regimens. No relevant studies were identified for bipolar disorder or psychosis.

CONCLUSION

Differences in study design and adherence measures used across the studies were too large to allow pooling of all results. Despite these differences, there was a consistent trend of better adherence with less frequent dosing.

Adherence to antiepilepsy drug therapy

Adherence to antiepilepsy drug (AED) therapy is critical for effective disease management, yet adherence and persistence rates are low due to several barriers. The definitions of adherence (80% rate of total pills taken, medication possession ratio, and days covered by prescriptions filled) and methods of measurement (patient self-reports, serum drug levels, pill counts, electronic bottle tops, and reviews of pharmacy records) are not without limitations, and their applicability to epilepsy is not clear. The use of simple adherence scales during office visits can provide an overall impression of a patient's adherence and can serve as a basis for practitioner-patient dialog. Efforts to improve adherence should focus on provider and healthcare system determinants versus those focused only on the patient. These interventions include non-judgmental communication, patient education, simplification of the dosage regimen with once-daily therapies, and the use of patient reminders.

Impact of dose frequency on compliance and health outcomes: a literature review (1966-2006)

In order for treatments to be effective, patients must be compliant with their medication regimens. Currently, patient compliance is seen as one of the most challenging issues in treating patients with chronic diseases. Studies in which dose frequency has been changed have been reviewed across several different diseases to examine the impact of a change in dose frequency on compliance and health outcomes, as well as efficacy and tolerability. In general, reducing dose frequency may improve medication compliance and effectiveness, and reduce adverse events, while possibly reducing healthcare costs. Suggestions for future research have been presented, including a need to measure compliance with injectable formulations and a standardized definition of compliance.

Effects of the abrupt switch from solution to modified-release granule formulation of valproate

BACKGROUND

A new modified-release (MR) granule formulation of valproate (VPA) has been recently developed for the treatment of children with epilepsy. It consists of tasteless microspheres that can be sprinkled on soft foods and easily swallowed. There are no data on the effectiveness of this formulation in pediatric age.

AIM OF THE STUDY

To evaluate the effects of the abrupt switch from solution to VPA MR granules in children undergoing chronic treatment.

METHODS

We enrolled children receiving VPA solution as sole or adjunctive therapy and switched them to MR granules at identical dosages. VPA blood level, treatment efficacy (clinical and EEG data), tolerability (adverse reactions), palatability, ease of administration, and compliance were evaluated before switching (T0) and after 4 weeks (T1).

RESULTS

Out of 112 enrolled children, 108 (96.4%) completed the evaluation. We observed no significant differences between the patients at T0 and T1 in VPA blood levels, treatment efficacy, tolerability, and compliance. MR granules were judged more palatable (P < 0.05) and easier to administer (P < 0.05) than solution by children and parents. At 6-month follow-up, all patients continued to use MR granules.

CONCLUSION

Modified-release granule formulation of VPA may be a reliable alternative to solution for its convenience of use.

Preparation of Coated Valproic Acid and Sodium Valproate Sustained-release Matrix Tablets

The aim of this research was to investigate the technique for preparation of coated valproic acid and sodium valproate sustained-release matrix tablets. Different diluents were tested and selected as the effective absorbent for oily valproic acid. Effect of the amount of absorbent and hydroxypropylmethylcellulose on drug release from valproic acid-sodium valproate matrix tablets prepared with wet granulation technique was evaluated in pH change system. Colloidal silicon dioxide effectively adsorbed liquid valproic acid during wet granulation and granule preparation. The amounts of colloidal silicon dioxide and hydroxypropylmethylcellulose employed in tablet formulations affected drug release from the tablets. The drug release was prominently sustained for over 12 h using hydroxypropylmethylcellulose-based hydrophilic matrix system. The mechanism of drug release through the matrix polymer was a diffusion control. The drug release profile of the developed matrix tablet was similar to Depakine Chrono^®, providing the values of similarity factor (f2) and difference factor (f1) of 85.56 and 2.37, respectively. Eudragit^® L 30 D-55 was used as effective subcoating material for core matrix tablets before over coating with hydroxypropylmethylcellulose film with organic base solvent. Drug release profile of coated matrix tablet was almost similar to that of Depakine Chrono^®.

Self-reported medication adherence and treatment satisfaction in patients with epilepsy

OBJECTIVE

Reports about medication adherence and satisfaction in patients with epilepsy in Arab countries are lacking. The objective of this study was to assess medication adherence and its relationship with treatment satisfaction, number of antiepileptic drugs (AEDs) taken, and epilepsy control in a sample of Palestinian patients.

METHODS

This cross-sectional descriptive study was carried out at Al-Makhfya Governmental Outpatient Center in Nablus, Palestine, during the summer of 2010. A convenience sampling method was used to select patients over the study period. Medication adherence was measured using the eight-item Morisky Medication Adherence Scale (MMAS); treatment satisfaction was measured using the Treatment Satisfaction Questionnaire for Medication (TSQM 1.4). Epilepsy was arbitrarily defined as "well controlled" if the patient had had no seizures in the last 3 months and was defined as "poorly controlled" if he or she had had at least one seizure in the last 3 months.

RESULTS

A convenience sample of 75 patients was studied. On the basis of the MMAS, 11 patients (14.7%) had a low rate, 37 (49.3%) had a medium rate, and 27 (36%) had a high rate of adherence. Adherence was positively and significantly correlated with age (P=0.02) and duration of illness (P=0.01). No significant difference in adherence was found between patients with well-controlled and those with poorly controlled epilepsy. Similarly, there was no significant difference in adherence between patients on monotherapy and those on polytherapy. Mean satisfaction with respect to effectiveness, side effects, convenience, and global satisfaction were 73.6±20.7, 82.4±29.8, 69.5±15.5, and 68.4±18.3, respectively. There were significant differences in mean values in the effectiveness (P<0.01) and convenience (P<0.01) domains, but not the side effect (P=0.1) and global satisfaction (P=0.08) domains among patients with different levels of adherence. Patients on monotherapy had significantly higher satisfaction in the effectiveness domain (P=0.04) than patients on polytherapy. Similarly, patients with well-controlled epilepsy scored significantly higher in the Effectiveness (P=0.01) and Global Satisfaction (P=0.01) domains than those with poorly controlled epilepsy.

CONCLUSION

In our convenience sample, we found that adherence to and satisfaction with AEDs were moderate and were not associated with seizure control or number of AEDs.

The relationships among medicine symptom distress, self-efficacy, patient-provider relationship, and medication compliance in patients with epilepsy

The purpose of this study was to investigate the relationships among medicine symptom distress, self-efficacy, patient-provider relationship, and medication compliance in patients with epilepsy. Patients with epilepsy (n=357) were recruited using convenience sampling from three medical centers in northern Taiwan. Results showed significant differences in relationships between medication compliance and the following factors: gender, employment status, comorbid chronic diseases, self-driving, daily drug dosing frequency, seizure after a missed dose, and self-efficacy. Logistic regression analysis indicated that comorbid chronic disease, self-driving, seizure after a missed dose, and self-efficacy were significantly associated with medication compliance. These data suggest that health care providers of patients with epilepsy pay more attention to treatment of comorbid chronic diseases, the safety issues of self-driving, seizures occurring after missed doses, and awareness of self-efficacy.

Extended-release formulations of antiepileptic drugs: rationale and comparative value

Extended-release products are designed to prolong the absorption of drugs with short half-lives, thereby allowing longer dosing intervals while minimizing fluctuations in serum drug levels. The relationship between serum drug concentration and clinical effects of antiepileptic drugs (AEDs) can be complex and reducing fluctuations in serum drug levels is not equally advantageous for all AEDs. Extended-release formulations have been shown to be particularly valuable for carbamazepine, whereas for other AEDs advantages, other than prolongation of the dosing interval, have not been clearly demonstrated. Differences in bioavailability may exist between extended-release and immediate-release formulations and among different brands of extended-release products. Therefore, when switching from one formulation to another, careful monitoring of clinical response and attention to the need for dose adjustment are warranted.

Once-daily dosing is appropriate for extended-release divalproex over a wide dose range, but not for enteric-coated, delayed-release divalproex: evidence via computer simulations and implications for epilepsy therapy

Divalproex sodium extended-release (divalproex-ER), administered once-daily, maintains plasma valproic acid (VPA) concentrations for 24h, whereas enteric-coated, delayed-release divalproex sodium (divalproex) requires multiple-daily doses to do the same. We hypothesize that a once-daily divalproex regimen should not be administered to epilepsy patients requiring high total daily doses, e.g., 35.6-56 mg/kg/day, due to the potential for high (>125 mg/L) maximum VPA concentrations (C(max)). We examined the impact of once-daily dosing, divalproex vs. divalproex-ER, on steady-state plasma VPA concentration-time profiles at commonly used doses in monotherapy (uninduced) and polytherapy (hepatic enzyme-induced) virtual adult patients. Only the 1125 mg once-daily divalproex dose had mean C(max)<100mg/L; >or=2000 mg produced mean C(max)>or=125 mg/L. Mean divalproex C(min) was approximately 50 mg/L at two of four doses tested, whereas mean ER C(min) was >73 mg/L at all doses tested. Once-daily divalproex peak-trough fluctuation was 4.4-6.2-fold greater than once-daily divalproex-ER. We predict that excursions beyond the conventional recommended VPA plasma concentration range will commonly occur with high total mg daily doses (>or=2000 mg) of enteric-coated divalproex, if dosed once-daily, potentially producing clinical toxicity. This divalproex formulation should not be dosed once-daily at high total mg daily doses due to this risk. Divalproex-ER is the appropriate formulation for administration on a once-daily basis, especially if large total mg/day doses are required for the control of seizure activity.

Difficult to swallow: patient preferences for alternative valproate pharmaceutical formulations

OBJECTIVE

To determine the degree to which swallowing valproate (VP) tablets is an issue, the proportion of patients who would prefer an alternative formulation, and the predictors of preference.

METHODS

A quantitative telephone survey of eligible adults (n = 400, >/=18 years old) who currently take (n = 236) or previously took (n = 164) VP tablets within the past 6 months was conducted.

RESULTS

More than half of the patients indicated that VP tablets were 'uncomfortable to swallow' (68.5%, n = 274) and were 'very interested' (65.8%, n = 263) in medications that were easier to swallow. When choosing conceptually between taking VP tablet once/day or an equally safe and effective but significantly smaller soft gel capsule twice per day, the 82.8%, (n = 331) preferred the soft gel capsule. In the multivariate regression analysis, perceiving soft gel capsules to be easier to swallow (OR = 73.54; 95% CI = 15.01 to 360.40) and taking VP more frequently (OR = 2.02; 95% CI = 1.13 to 3.61) were significant predictors of soft gel capsule treatment preference.

CONCLUSION

VP users would prefer a formulation that is easier to swallow, even if it is needed to be taken twice per day. When choosing between medications with similar efficacy and safety, physicians can consider patient preferences to optimize conditions for medication adherence.

Overnight versus progressive conversion of multiple daily-dose divalproex to once-daily divalproex extended release: which strategy is better tolerated by adults with intellectual disabilities?

Divalproex (DVP) delayed release and DVP extended release (DVP ER) are approved by the Food and Drug Administration for bipolar disorder, epilepsy, and migraine prophylaxis. Divalproex ER is given once daily, improving compliance and reducing adverse events. Overnight switch to DVP ER is advised in the package insert but could produce more adverse events in this susceptible population. In this pilot study, we compared tolerability of overnight versus gradual switching to DVP ER in 16 adults with intellectual and developmental disabilities receiving DVP, in 9 for epilepsy and in all 16 for comorbid bipolar disorder. The study design was open with parallel groups. Sixteen subjects with intellectual and developmental disabilities were randomized to overnight or gradual conversion for 4 to 6 days. A blinded rater completed the Multidimensional Observation Scale for Elderly Subjects on days +1, +4, and +8 after the switch began. We found no major differences between the 2 groups at each time point. Neither group of subjects, except for 1 subject in the overnight group, manifested sedation, seizures, worsening of tremor, or gastrointestinal adverse events. One subject in the overnight group manifested acute diarrhea and vomiting, followed by a very brief tonic leg seizure 6 days later. Larger studies are warranted.

Best clinical and research practice in epilepsy of older people: Focus on antiepileptic drug adherence

Few studies have examined the issues that are specific to the older person with epilepsy, a population of increasing prominence in epilepsy management. Our understanding of the impact of epilepsy in the older person is based predominantly on what is inferred from studies of younger adults. Consequently, there is relatively little documented about the impact of epilepsy on the everyday lives of older people. In this article, we focus on adherence and its consequences for the physical, social, and psychological well-being of the older person. A number of strategies are proposed to improve adherence, including patient education through better communication between physician and patient; simplification of the medical regime; and use of extended-release formulations. This issue highlights that to ameliorate the impact of epilepsy for the older person with epilepsy, a greater understanding is required so that appropriate interventions can be tailored.

Comparative in vivo bioequivalence and in vitro dissolution of two valproic acid sustained-release formulations

Objective

A study was conducted to establish the bioequivalence between different sustained-release formulations of valproic acid (Depakene R and Selenica R), which were developed in Japan.

Materials and methods

The clinical investigation was designed in a randomized, crossover fashion with a single dose given to 12 healthy subjects. The subjects were administered a single 600 mg dose of valproic acid in one of two formulations. Serial venous blood samples were obtained over 72 hours after each administration to measure valproic acid in serum by enzyme immunoassay (EIA). In addition, a dissolution test was performed. Each sample was analyzed by an high-performance liquid chromatography to determine the dissolution rate of valproic acid.

Results

No difference in maximum concentration or area under the curve was found between the two formulations. The time to maximum concentration of the new formation was significantly delayed compared with the conventional formulation (10.8 ± 1.7 versus 17.6 ± 1.8 hours, p < 0.001). Apparent clearance or elimination half-life did not differ between the two formulations. An in vitro dissolution study showed that Depakene R was significantly more dissoluble than Selenica R.

Conclusion

Based on the results, the present study demonstrated a significant difference between the two sustained-release formulations in the absorption profile, and also demonstrated that the bioavailability of valproic acid in the two formulations was similar but absorption speed (lag time) was very different.

Association of non-adherence to antiepileptic drugs and seizures, quality of life, and productivity: survey of patients with epilepsy and physicians

Non-adherence to epilepsy medications can interfere with treatment and may adversely affect clinical outcomes, although few studies have examined this relationship. This study assessed barriers and drivers to adherence, its impact on quality of life, and the importance of the patient-physician relationship to adherence. Two cross-sectional online surveys were conducted among 408 adult patients with epilepsy and 175 neurologists who treat epilepsy patients. Twenty-nine percent of patients self-reported being non-adherent to antiepileptic medications in the prior month. Non-adherence was found to be associated with reduced seizure control, lowered quality of life, decreased productivity, seizure-related job loss, and seizure-related motor vehicle accidents. Patient-oriented epilepsy treatment programs and clear communication strategies to promote self-management and patients' understanding of epilepsy are essential to maximizing treatment and quality of life outcomes while also minimizing economic costs.

Extended-release formulations for the treatment of epilepsy

This review analyses the concept of extended-release (ER) formulations in epilepsy and evaluates ER formulations of carbamazepine, valproic acid and a modified-release (MR) formulation of oxcarbazepine. ER formulations are usually designed to reduce dose frequency and maintain relatively constant or flat plasma drug concentration. It is questionable whether flat plasma concentrations of an antiepileptic drug (AED) improve antiepileptic efficacy compared with fluctuating plasma concentrations. More certainly, they minimise concentration-related adverse effects, and the dosing flexibility and consistency of plasma concentrations may simplify the management of antiepileptic drug therapy. Neurologists would like ER formulations that can be administered once- and/or twice-daily to tailor therapy for the individual patient; however, switching dosage schedules from multiple dosages per day to once daily, although more convenient, will not generally improve therapeutic coverage (maintenance of effective drug concentration in biological fluids and tissue). Pharmacokinetically, the impact of a missed dose is greater the larger the dose and the less frequent the administration. Therefore, the risk of breakthrough seizure is higher during AED once-daily administration than twice-daily administration. Consequently, the increased compliance observed with fewer dosages per day should be weighed against the impact or forgiveness of omitted dose(s) and the shorter 'forgiveness' period associated with once-daily administration. Currently, the trend is to treat patients with epilepsy with ER formulations because of the better compliance, convenience and flat plasma concentration versus time curve. Thus, it seems that the term 'flatter is better' for AED plasma profiles has precipitated in the last 10-15 years among neurologists and epilepsy caregivers, and is being promoted by marketing forces of pharmaceutical companies. Data from the literature support the trend to treat epileptic patients with twice-daily administration of the existing ER formulations of valproic acid and carbamazepine, and oxcarbazepine-MR; however, the author of this article is not convinced that these ER formulations can guarantee a complete therapeutic coverage throughout the 24-hour dosing interval following once-daily administration. Epilepsy is a single-episode disease, and the convenience and possible better compliance associated with once-daily administration must be weighed against the shorter 'forgiveness' period and possible higher risk of breakthrough seizure due to sub-therapeutic plasma levels and/or omitted doses. Data suggest just a small difference in compliance between once- and twice-daily administration, with no significant difference in efficacy. Therefore, the increased compliance following once-daily administration may be counter-productive in minimising the occurrence of sub-therapeutic drug concentrations. Weighing up the advantages and disadvantages for once- versus twice-daily administration of ER formulations in epilepsy leads to a conclusion in favour of twice-daily administration.

Comparative retention rates and long-term tolerability of new antiepileptic drugs

OBJECTIVE

Retention rates of five new anti-epileptic medications (AEDs) were compared in order to evaluate their long-term tolerability and efficacy.

METHOD

We acquired the retention data on levetiracetam (LEV), lamotrigine (LTG), oxcarbazepine (OXC), topiramate (TPM), and zonisamide (ZNS) from the electronic database. The data included patient's age, gender, seizure type, current and previous medications, dosage, main reasons for discontinuation, and duration of therapy. The retention rates of these AEDs were evaluated at 4, 12, 24, 52, and 104 weeks.

RESULTS

A total of 828 new AED exposures were obtained (LEV=196, LTG=251, OXC=97, TPM=156, ZNS=128) from patients with partial or generalized epilepsy. At 2 years, retention rate was highest with LTG (74.1%), followed by ZNS (60.2%), OXC (58.8%), LEV (53.6%), and TPM (44.2%). When these AEDs were discontinued, it was mainly due to inefficacy (29.5%) and sedating side-effects (20.5%), and commonly within 6 months into therapy. Several important AED specific side-effects leading to discontinuation were identified, including behavioral or irritability from LEV, rash from LTG and OXC, nausea from OXC and ZNS, hyponatremia from OXC, and kidney stones from TPM and ZNS.

CONCLUSION

Comparing retention rates of new AEDs can provide useful insight into their tolerability and efficacy. This study showed highest retention rate with LTG, which was significantly different from ZNS (p=0.0025), LEV (p<0.0001), OXC (p=0.0024), and TPM (p<0.0001). Beside ineffectiveness, other leading causes of discontinuation were adverse behavioral effects with LEV, rash with LTG and OXC, and sedation for TPM and ZNS.

Different serum concentrations of steady-state valproic acid in two sustained-release formulations

Recently a new sustained-release formulation of valproic acid has been developed in Japan. The sustained-release mechanism of the new formulation was different from the conventional formulation. The aim of the present study was to compare the pharmacokinetic characteristics of valproic acid in two sustained-release formulations. Different sustained-release formulations of valproic acid (Depakene R and Selenica R) were administered in a randomized cross-over fashion in repeated doses in 24 psychiatric patients. After > or = 4 weeks administration of valproic acid once daily, blood samples were taken just before (0 h) and 8, 12, 24 h after the morning dose. Blood sampling was performed in the same manner in the same patients 4 weeks after switching from one to the other formulation of valproic acid. Serum concentrations of valproic acid at 0 h (50.7 +/- 19.4 vs 44.9 +/- 21.8 microg/mL, P < 0.05) and 24 h (52.3 +/- 19.54 vs 6.2 +/- 22.2 microg/mL, P < 0.05) were significantly higher during Selenica R than during Depakene R treatment, whereas the serum concentration of valproic acid at 8 h (49.7 +/- 19.2 vs 62.4 +/- 25.6 microg/mL, P < 0.01) was significantly lower during Selenica R treatment than during Depakene R treatment. Serum concentrations of valproic acid at 12 h were not different. The present study demonstrated that steady-state serum concentrations were different because of the different dissolution profiles. When a prescription for valproic acid is switched from one drug to the other, prescribers should be aware that the therapeutic drug monitoring data are not consistent.

Managing patient adherence and quality of life in epilepsy

Patient adherence to medication continues to be a cause of concern within the medical profession. This review examines the various methods of quantifying the level of patient adherence, progress in predicting causes of non-adherence, and the implications for its management. Contributions from the medical, health belief, and psychosocial models are discussed in order to highlight how the concept of adherence has changed over time. The impact of epilepsy, seizures, and taking antiepileptic drugs (AEDs) on both adherence and quality of life are also explored. The volume and quality of previous research conducted has enabled a number of predictive factors to be identified, from which various strategies have been developed. While this review concentrates on potential strategies in managing treatment adherence within epilepsy, findings can equally be applied to other chronic conditions.

Conventional and sustained-release valproate in children with newly diagnosed epilepsy: a randomized and crossover study comparing clinical effects, patient preference and pharmacokinetics

OBJECTIVE

It has been suggested that sustained-release valproate (VPA) formulations may be more effective and better tolerated than conventional VPA due to better compliance and lower fluctuations in VPA serum concentrations, but comparative trials with conventional VPA in children are scarce. This randomized and crossover trial compared the efficacy (complete control of seizures), the tolerability, and the patient (or parents) preference of conventional VPA twice daily (CVbid) with those of sustained-release chrono VPA twice daily (ChVbid), once daily in the morning (ChVom) or once daily in the evening (ChVoe) in monotherapy.

METHODS

The study was carried out in 48 children (29 girls), aged 5-14 years, with newly diagnosed partial epilepsy (n=26), or idiopathic generalized epilepsy (n=22). The study duration was 16 months (four phases of 4 months each). VPA pharmacokinetics data were also compared in the different regimens. Mean VPA dosage was of approximately 870 mg/day (approximately 22 mg/kg/day) and mean VPA concentration was of approximately 89 mg/l at 12 h post-dose and of 54 mg/l at 24 h post-dose.

RESULTS

By intention in treatment there were no significant differences in efficacy (73%, 83%, 77% and 75%, respectively) or in adverse reaction frequency (56%, 58%, 67% and 46%, respectively). There were significant differences, however, in patient (or parents) preference, the order being ChVoe (31%) > ChVom (25%) > CVbid (17%) > ChVbid (8%). The mean VPA serum concentration fluctuation between 4 h and 0 h post-morning-dose was nonsignificantly lower after CVbid than after ChVbid. Fluctuation was significantly higher after ChVom than after CVbid or ChVbid. The mean VPA serum concentration difference between 12 h and 24 h post-dose was approximately 40 mg/l.

CONCLUSION

Although our results should be confirmed by a larger study, they suggest that the efficacy and tolerability of chrono valproate is similar to that of conventional valproate, and that the main advantage is the once-daily administration.

Does It Really Matter When a Blood Sample for Valproic Acid Concentration is Taken Following Once-Daily Administration of Divalproex-ER?

Divalproex sodium extended-release (divalproex-ER) is a novel formulation intended for once-daily oral administration, either morning or evening. Questions have risen concerning the optimal time for obtaining a blood sample for valproic acid (VPA) concentration in relation to the dose. Trough sampling is easily achieved just before a morning daily dose, but the best time to sample after an evening daily dose is unclear, because collecting a blood sample 21 to 24 hours later may be limited by the operational hours of the laboratory. This investigation provides practical guidance regarding blood sample timing. Steady-state plasma VPA concentration-time profiles from 5 published divalproex-ER studies (healthy subjects and epilepsy patients) were analyzed. The concentration-time profile for each subject/patient was expressed as a percentage of his/her trough concentration and summary statistics computed. Typically, when taking divalproex-ER once daily in the morning, a blood sample collected 21 to 24 hours later is expected to have a concentration within 3% of the trough value. Conversely, for divalproex-ER dosed once-daily in the evening, for example 8 PM, a blood draw 12 to 15 hours later (ie, 8 to 11 AM) will give a plasma VPA concentration value that is 18% to 25% higher, on average, than the trough value. However, waiting longer, (for example 18 to 21 hours, ie 2 to 5 PM) will result in concentration values that are merely 3% to 13% higher than trough values, which may provide acceptable information for monitoring purposes. The greatest deviation from trough VPA concentration occurs around the peak, that is 3 to 15 hours after a once-daily divalproex-ER dose; sampling during this time period is recommended only if a clinical need exists to test for a higher VPA concentration. Despite the apparent smoothness of the VPA concentration-time profile after a once-daily divalproex-ER dose, the timing of the blood sample does matter and impacts the proper interpretation of the VPA concentration.

Optimizing epilepsy management in teenagers

Optimal epilepsy management in teenage patients represents a particular challenge. These patients are often likely to respond more positively to a regimen that least disrupts their activities. In addition, as a patient group, they are more sensitive to peer perception. Current perceptions of older antiepilepsy drugs do not take into account frequent undesirable side effects or potential adverse interactions with other drugs. Furthermore, they often do not completely control seizures. Recent data suggest that not only do the newer antiepileptic drugs appear to be as efficacious as the older drugs, they also often have more favorable cognitive, cosmetic, and teratogenic side-effect profiles. In addition, newer antiepileptic drugs are being used more often in monotherapy. Successful management of epilepsy in teenagers requires that physicians not only understand the advantages that the newer antiepileptic drugs appear to provide but also consider the social impact of treatment on their patients.

Every-12-hour administration of extended-release divalproex in patients with epilepsy: impact on plasma valproic acid concentrations

Extended-release divalproex sodium (divalproex-ER) biopharmaceutics after every-12-hour (q12h) administration was compared with that of once-daily divalproex-ER and conventional divalproex given every 6 hours (q6h) in a multiple-dose (14-day), randomized, three-period crossover design study in 24 patients with epilepsy concomitantly receiving enzyme-inducing antiepileptic medication(s). Plasma valproic acid (VPA) minimum concentration (Cmin) for divalproex-ER q12h was higher than the once-daily divalproex-ER Cmin (P=0.043). Once-daily divalproex-ER Cmin values were not different from those for divalproex q6h, suggesting that adequate trough steady-state concentrations are maintained with once daily dosing, despite enzyme-inducing comedication. The degree of peak-trough fluctuation (DFL, calculated as (Cmax-Cmin)/Cavg) in VPA concentration was less with both q12h (35.2% less) and once-daily (16.9% less) divalproex-ER regimens compared with q6h divalproex (P0.024). The DFL for divalproex-ER dosed as a q12h regimen was 22% less than that for once-daily divalproex-ER (P=0.02). The DFL in VPA concentration with divalproex-ER can be minimized with once-daily administration and more so with q12h administration, compared with conventional enteric-coated divalproex taken q6h.