Drug absorption in the elderly: biopharmaceutical considerations for the antiepileptic drugs

Early versus late switch over of antiseizure medications from intravenous to the oral route in children with seizures: Single-blinded, randomized controlled trial (ELAIO trial)

INTRODUCTION

Early switch-over of anti-seizure medications (ASMs) from intravenous to oral route may reduce the duration of hospitalization, drug acquisition costs, and behavioral upset in hospitalized children with seizures.

OBJECTIVE

The primary objective was to compare short-term seizure recurrence within 1 week in hospitalized children aged 1 month to 18 years with new-onset/breakthrough seizures after an early versus late switch-over from intravenous to the oral route of ASMs. Secondary objectives were to compare the incidence of status epilepticus, duration of hospital stay, drug acquisition costs, and caregiver-reported satisfaction scores in both groups.

METHODS

In this single-blind randomized controlled trial, patients with seizures were categorized based on the number of ASMs required and the history of status epilepticus. Patients in each category were randomized in a 1:1 ratio into either early or late switch-over (ES or LS) groups. In the ES groups, ASMs were tapered one-by-one between 0 and 24 hours of seizure freedom, while in the LS groups, they were tapered one-by-one between 24 and 48 hours of seizure freedom.

RESULTS

A total of 112 children were enrolled in the study, with 56 in each arm. Seizure recurrence at 1 week and 12 weeks was comparable in ES and LS groups (3/55 vs. 1/54 at 1 week, p=0.61; 7/49 vs. 6/49 at 12 weeks, p=0.98). Drug acquisition costs were significantly lower in the ES group (393±274 vs. 658±568 INR, p=0.002). Thrombophlebitis and dysphoria were significantly more common in the LS group (p=0.008 and 0.03, respectively).

CONCLUSION

The early switch-over of ASMs from intravenous to oral route is safe without any significant increased risk of short-term seizure recurrence and also associated with a reduction in the incidence of thrombophlebitis and ASM acquisition costs.

TRIAL REGISTRATION NO

CTRI/2021/03/032145.

New Drug Delivery Systems for Stable Oral Absorption: Theory, Strategies, and Applications

The oral dosage route still remains the most common and preferred route for drug administration due to convenient handling, high patient compliance, and cost-effectiveness. However, the oral absorption of drugs can be a complex process depending upon: (i) physicochemical properties of the drug (e.g., pKa, lipophilicity, solubility), (ii) pharmaceutical factors (e.g., dosage form), and (iii) physiological factors (e.g., gastrointestinal pH values, gastric emptying rate, gastric and intestinal pH, metabolism). Oral administration of drugs sometimes leads to poor and/or variable oral bioavailability, possible leading to unstable clinical outcomes. To offer stable and improved pharmacokinetic behavior of drugs, a number of formulation approaches have been developed with a focus on enhancement of the solubility, dissolution rate, and oral bioavailability of drugs. To provide new formulation platforms for better and safe medication, it is considered essential to understand the physicochemical, biochemical, metabolic, and biological barriers which limit overall drug bioavailability in more detail. The review article considers several crucial factors affecting oral absorption of drug substances. This article also describes the recent progress in formulation approaches to achieve stable and improved biopharmaceutical properties of orally-taken drugs.

Alteration of sphingosine-1-phosphate with aging induces contractile dysfunction of colonic smooth muscle cells via Ca2+ -activated K+ channel (BKCa ) upregulation

BACKGROUND

Age-associated changes alter calcium-activated potassium channel (BK_Ca ) expression of colon. Sphingolipids (SLs) are important cell membrane structural components; altered composition of SLs may affect BK_Ca expression. This study investigated the mechanism by which sphingosine-1-phosphate (S1P) contributes to age-associated contractile dysfunction.

METHODS

Fifty male Sprague Dawley rats of different ages were randomly assigned to five age-groups, namely 3, 6, 12, 18, and 24 months. BK_Ca expression, S1P levels, and phosphorylated myosin light chain (p-MLC) levels were tested in colonic tissues. In the absence and presence of S1P treatment, BK_Ca expression, p-MLC levels, and intracellular calcium mobilization were tested in vitro. BK_Ca small interfering RNA (siRNA) was used to investigate whether p-MLC expression and calcium mobilization were affected by BK_Ca in colonic smooth muscle cells (SMCs). The expressions of phosphorylated protein kinase B, c-Jun N-terminal kinases (JNKs), extracellular-regulated protein kinases, nuclear factor kappa-B (NF-κB), and protein kinase C_ζ (PKC_ζ ) were examined to investigate the correlation between S1P and BK_Ca .

KEY RESULTS

Sphingosine-1-phosphate levels and sphingosine-1-phosphate receptor 2 (S1PR2) and BK_Ca expressions were upregulated and p-MLC expression was downregulated in the colonic tissues, age dependently. In the cultured SMCs, S1P treatment increased BK_Ca expression and reduced calcium concentration and p-MLC was observed. BK_Ca siRNA increased calcium concentration, and p-MLC levels significantly compared with control. We also showed that S1P upregulated BK_Ca through PKC_ζ , JNK, and NF-κB pathways.

CONCLUSIONS AND INFERENCES

In conclusion, S1P and S1PR2 participate in age-associated contractile dysfunction via BK_Ca upregulation through PKC_ζ , JNK, and NF-κB pathways.

Psychopharmacology and pharmacokinetics

The overall physiologic changes associated with aging lead to changes in both pharmacokinetic and pharmacodynamic actions of many medications. This, in turn, leads to changes in the impact that a wide variety of medications have on older adults when compared to younger, healthy individuals. These pharmacokinetic and pharmacodynamic variations can cause either lesser or greater than expected responses to medication. Knowledge of the physiologic changes that are expected to occur in the elderly can help to identify medications that may require dose adjustments or that should be avoided, due to increased risk in this population. As a general principle, medications should be started at lower doses in the elderly with slow titration schedules to reduce the risk of adverse effects.

Lamotrigine pharmacokinetics following oral and stable-labeled intravenous administration in young and elderly adult epilepsy patients: Effect of age

OBJECTIVE

The objectives of this study were to investigate the effect of age on pharmacokinetic parameters of lamotrigine (LTG) and estimate parameter variability.

METHODS

Patients (>18 years old) who were already on a steady-state dose of LTG therapy with no interacting comedications were enrolled. Patients with significant cardiac disease, severe kidney dysfunction, or moderate-to-severe liver dysfunction were excluded. Fifty milligrams of a stable-labeled intravenous LTG formulation (SL-LTG) replaced 50 mg of a patient's normal daily oral LTG dose. Thirteen blood samples were collected in each person over 96 hours. SL-LTG and unlabeled LTG concentrations were measured simultaneously by gas chromatography-mass spectrometry. Concentration-time data were analyzed by nonlinear mixed-effects modeling (NONMEM version 7.3).

RESULTS

Twenty-eight patients representing 16 young (18-48 years old) and 12 elderly (63-87 years old) patients were included, yielding 382 unlabeled and 351 SL-LTG concentrations. A two-compartment model with first-order absorption and elimination adequately described the plasma concentration-time data. Bioavailability of oral LTG was approximately 74% and did not differ by age. LTG clearance was 27.2% lower in elderly than in young patients (1.80 L/h for a 70-kg patient).

SIGNIFICANCE

Although LTG bioavailability was not affected by age, LTG clearance was 27.2% lower in elderly versus young patients of comparable body weight, possibly indicating lower dosages being needed in this population.

Review of antimicrobial use and considerations in the elderly population

Pharmacologic management of infections in elderly patients presents multiple challenges to health care professionals due to variable pharmacokinetics, pharmacodynamics, and immune function. Age is a well-established risk factor for infection, but furthermore is a risk factor for prolonged length of hospital stay, increased incidence of complications, and significant and sustained decline in baseline functional status. In 2014, 46.2 million Americans were aged ≥65 years, accounting for 14.5% of the total population. By 2033, for the first time, the population of persons aged ≥65 years is projected to outnumber the people <18 years of age. According to the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey, 154 million prescriptions for antimicrobials were estimated to have been written in doctors’ offices and emergency departments during a 1-year time period. In 2014, 266.1 million courses of antimicrobials were dispensed to outpatients by US community pharmacies. A study that evaluated 2007–2009 Medicare Part D data found that patients aged ≥65 years used more antimicrobials, at 1.10 per person per year, compared to 0.88 antimicrobials used per person per year in patients aged 0–64 years. With the abundance of antimicrobial prescriptions and the current growth in the number and proportion of older adults in the US, it is essential that health care providers understand appropriate antimicrobial pharmacotherapy in the elderly patient. This review focuses on the use and implications of antimicrobial agents in the elderly population.

Euro-Esli: a European audit of real-world use of eslicarbazepine acetate as a treatment for partial-onset seizures

The Euro-Esli study was an exploratory pooled analysis of data from 14 European clinical practice studies, which was conducted to audit the real-world effectiveness, safety, and tolerability of eslicarbazepine acetate (ESL) as an adjunctive treatment for partial-onset seizures. Retention and effectiveness were assessed after 3, 6, and 12 months of ESL treatment, and at the final visit. Safety and tolerability were assessed throughout ESL treatment by evaluating adverse events (AEs) and ESL discontinuation due to AEs. Data from 2058 patients (52.1% male; mean age 44.0 years) were included. All 2058 patients were assessed for safety and 1975 (96.0%) patients were assessed for effectiveness. After 12 months, retention, responder (≥50% seizure frequency reduction), and seizure freedom rates were 73.4, 75.6, and 41.3%, respectively. AEs were reported for 34.0% of patients and led to discontinuation in 13.6% of patients. The most frequently reported AEs were dizziness (6.7% of patients), fatigue (5.4%), and somnolence (5.1%). No unexpected safety signals emerged over a median duration of follow-up of >5 years. Subgroup analyses revealed that ESL was significantly more effective in patients aged ≥65 versus <65 years, in patients who were not receiving treatment with other sodium channel blockers versus those who were receiving treatment with other sodium channel blockers, and in patients who were receiving <2 versus ≥2 concomitant antiepileptic drugs at baseline. Euro-Esli is the largest ESL clinical practice study conducted to date. This study provides strong and reassuring evidence of ESL’s safety profile, and complements the data from clinical trials.

Effect of age on the pharmacokinetics of polymorphic nimodipine in rats after oral administration

The previous investigation has proved that their existed pharmacokinetic difference between the different crystal forms of the polymorphic drugs after oral administration. However, no systemic investigations have been made on the change of this pharmacokinetic difference, resulted either from the physiological or from the pathological factors. In this paper, we used polymorphic nimodipine (Nim) as a model drug and investigated the effect of age difference (2- and 9-month old) on the pharmacokinetics after oral delivery in rats. As the results shown, for L-form of Nim (L-Nim), the AUC_0-24 h in 2-month-old rats was 343.68±47.15 ng·h/mL, which is 23.36% higher than that in 9-month-old rats. For H-form of Nim (H-Nim), the AUC_0-24 h in 2-month-old rats was 140.91±19.47 ng·h/mL, which is 54.64% higher than that in 9-month-old rats. The AUC_0-24 h ratio between H-Nim and L-Nim was 2.44 in 2-month-old rats and 3.06 in 9-month-old rats. Since age difference could result in unparallelled change of the absorption and bioavailability of the polymorphic drugs, the results in this experiment are of value for further investigation of crystal form selection in clinical trials and rational clinical application of the polymorphic drugs.

Age related differences in the plasma kinetics of flavanols in rats

Dietary flavanols produce beneficial health effects; once absorbed, they are recognized as xenobiotics and undergo Phase-II enzymatic detoxification. However, flavanols with a degree of polymerization greater than 2 reach the colon, where they are subjected to microbial metabolism and can be further absorbed and undergo Phase-II reactions. In this sense, flavanols' health-promoting properties are mainly attributed to their metabolic products. Several age-related physiological changes have been evidenced, and it is known that flavanols' bioavailability is affected by internal factors. Therefore, this study aimed to elucidate whether animals of different ages, specifically young and adult rats, exhibit differences in their flavanol metabolism and plasma bioavailability. To accomplish this, an acute dose of a grape seed polyphenol extract was administered to male rats; after 2, 4, 7, 24 and 48 h, flavanols and their Phase-II and microbial metabolites were quantified by HPLC-ESI-MS/MS in plasma. The results indicated important age-related quantitative differences in plasma flavanol metabolites. Interestingly, adult rats presented a remarkable reduction in flavanol absorption and Phase-II flavanol metabolism. Consequently, microbial-derived flavanol metabolism is triggered by higher flavanol affluence in the colonic tract. Furthermore, young rats presented a faster metabolic profile than adult rats. Hence, our results indicate that the physiological bioactivities of flavanols may depend on age.

Hookworm infection among patients with pulmonary tuberculosis: Impact of co-infection on the therapeutic failure of pulmonary tuberculosis

OBJECTIVE/BACKGROUND

The aim of this study is to determine the rate of hookworm infection among patients with pulmonary tuberculosis (TB) and to find out if there is a relation between hookworm infection and the therapeutic failure of pulmonary TB.

METHODS

We carried out a prospective, hospital-based study. The study included 231 naïve patients with pulmonary TB, consecutively. Patients were evaluated at the 4th month of therapy for persistence of Mycobacterium tuberculosis infection. All patients had clinical evaluation, laboratory investigations (including sputum culture and stool microscopic examination), and imaging studies (abdominal ultrasonography and chest radiography).

RESULTS

The study population mean age was 42.7±13.9 years old with 26.8% of them 40 years old or more. Out of 231 patients, 133 (57.6%) were men. Therapeutic failure rate of pulmonary TB was 29.4%. Hookworm infection was diagnosed among 16.5% of patients and 27.7% had diabetes mellitus (DM). Using multivariate analysis, it was found that age of 40 years or more (odds ratio [OR] 8.4; 95% confidence interval [CI] 1.7-41.3; p=.009), hookworm infection (OR 7.6; 95% CI 1.2-49.9; p=.034), and DM (OR 5.9; 1.2-28; p=.027) were independently associated with therapeutic failure of pulmonary TB among the study population with pulmonary TB.

CONCLUSION

In conclusion, the rate of therapeutic failure of pulmonary TB is high. Besides older age and DM, hookworm infection can reduce the therapeutic response of pulmonary TB. Screening for and control of DM and hookworm infection among patients with pulmonary TB may improve their therapeutic response.

Special population considerations and regulatory affairs for clinical research

Special populations, including women (non-pregnant and pregnant), pediatrics, and the elderly, require additional consideration with regard to clinical research. There are very specific regulatory laws, which protect these special populations, that need to be understood and adhered to in order to perform clinical research. This review provides a broad overview of some of the physiological differences in special populations and discusses how these differences may affect study design and regulatory considerations. These various special populations, with respect to regulatory affairs, are clearly defined within the Code of Federal Regulations. The definition of "special population" exists to provide enhanced awareness of their vulnerabilities, thereby allowing the creation of regulatory guidance aimed to decrease injury or outright harm. Currently, progress is being made to be more inclusive of special populations in clinical trials. This reflects changing attitudes towards drug information, with it being more representative of those patients that will ultimately be prescribed or exposed to the therapy. However, all research undertaken in these populations should be performed in a manner that ensures all protections of each participant are upheld.

Steady-state pharmacokinetics and bioavailability of immediate-release and extended-release formulations of lamotrigine in elderly epilepsy patients: Use of stable isotope methodology

A classic 2-period crossover bioavailability study was conducted to evaluate the relative and absolute bioavailability of immediate-release (IR) and extended-release (XR) lamotrigine formulations under steady-state conditions in elderly patients with epilepsy. On treatment days, each subject's morning dose (IR or XR lamotrigine) was replaced with an intravenous 50-mg dose of stable-labeled lamotrigine. Lamotrigine concentrations were measured at 13 points between 0 and 96 hours. XR and IR lamotrigine formulations were similar with respect to steady-state area under the concentration-time curve from 0 to 24 hours (AUC0-24 h ss), average concentration (Cavg, ss), and trough concentration (Cτ, ss). A 33% lower fluctuation in concentrations with XR was observed relative to IR lamotrigine. The time to peak concentration (Tmax, ss) was delayed for XR lamotrigine (3.0 vs 1.3 hours) with lower peak concentration (15% lower). The absolute bioavailability for IR and XR formulations was 73% and 92%, respectively. The formulations were bioequivalent with respect to AUC0-24 h ss, Cτ, ss, and Cavg, ss indicating that it may be possible to switch directly from IR to XR lamotrigine without changes in the total daily dose.

Advances in epilepsy treatment: lacosamide pharmacokinetic profile

Lacosamide (LCM) is a functionalized amino acid specifically developed for use as an antiepileptic drug (AED) and is currently indicated as adjunctive treatment for partial-onset seizures in adults with focal epilepsy (maximum approved dose 400 mg/day). Characterization of the pharmacokinetic profile is an important aspect in the development of LCM. Studies in healthy subjects and in patients with focal epilepsy have established that LCM has several favorable pharmacokinetic characteristics, including rapid absorption and high oral bioavailability not affected by food, linear and dose-proportional pharmacokinetics, low inter- and intraindividual variability, low plasma protein binding, renal elimination, and a low potential for clinically relevant pharmacokinetic drug-drug interactions both with AEDs and other common medications. Studies have demonstrated bioequivalence among the three LCM formulations (oral tablets, oral solution, and solution for intravenous (IV) infusion), allowing direct conversion to or from oral and IV administration without titration. Thus, the favorable and predictable pharmacokinetic profile and bioequivalence of LCM formulations, coupled with the low potential for clinically relevant pharmacokinetic drug-drug interactions, make LCM an easy-to-use adjunctive treatment for the management of patients with focal epilepsy.

Influence of ageing on the gastrointestinal environment of the rat and its implications for drug delivery

Age-mediated changes in gut physiology are considerations central to the elucidation of drug performance from oral formulations. Using rats of different age groups we measured the pH, buffer capacity, fluid volume, osmolality, and surface tension of gastrointestinal (GI) fluids, and therein explored the impact of these variables on prednisolone and mesalazine solubility in luminal fluids. We also studied the distribution of gut associated lymphoid tissue (GALT) and mucus layer thickness across the GI tract in rats of different age groups. At a mucosal level, there was an increase in GALT from young to adult rat. Gastrointestinal pH and buffer capacity remained mostly unchanged with age, except some pH differences in stomach and distal small intestine and a higher buffer capacity in the large intestinal fluids of young rats. Osmolality and surface tension also remained unaffected with the exception of a lower osmolality in elderly stomach and a lower surface tension in the small intestine of young rats. The difference in luminal environment on ageing influenced the solubility of studied drugs, for instance prednisolone solubility was shown to be higher in adult rats (mid small intestine and caecum) and solubility of mesalazine was significantly higher in the elderly distal small intestine.

Lack of effect of lacosamide on the pharmacokinetic and pharmacodynamic profiles of warfarin

PURPOSE

The aim of this study was to evaluate the effect of the antiepileptic drug lacosamide on the pharmacokinetics and pharmacodynamics of the anticoagulant warfarin.

METHODS

In this open-label, two-treatment crossover study, 16 healthy adult male volunteers were randomized to receive a single 25-mg dose of warfarin alone in one period and lacosamide 200 mg twice daily on days 1-9 with a single 25 mg dose of warfarin coadministered on day 3 in the other period. There was a 2-week washout between treatments. Pharmacokinetic end points were area under the plasma concentration-time curve (AUC(0,last) and AUC(0,∞) ) and maximum plasma concentration (Cmax ) for S- and R-warfarin. Pharmacodynamic end points were area under the international normalized ratio (INR)-time curve (AUCINR ), maximum INR (INRmax ), maximum prothrombin time (PTmax ) and area under the PT-time curve (AUCPT ).

KEY FINDINGS

Following warfarin and lacosamide coadministration, Cmax and AUC of S- and R-warfarin, as well as peak value and AUC of PT and INR, were equivalent to those after warfarin alone. In particular, the AUC(0,∞) ratio (90% confidence interval) for coadministration of warfarin and lacosamide versus warfarin alone was 0.97 (0.94-1.00) for S-warfarin and 1.05 (1.02-1.09) for R-warfarin, and the AUCINR ratio was 1.04 (1.01-1.06). All participants completed the study.

SIGNIFICANCE

Coadministration of lacosamide 400 mg/day did not alter the pharmacokinetics of warfarin 25 mg or the anticoagulation level. These results suggest that there is no need for dose adjustment of warfarin when coadministered with lacosamide.

Tuberculosis in ageing: high rates, complex diagnosis and poor clinical outcomes

BACKGROUND

worldwide, the frequency of tuberculosis among older people almost triples that observed among young adults.

OBJECTIVE

to describe clinical and epidemiological consequences of pulmonary tuberculosis among older people.

METHODS

we screened persons with a cough lasting more than 2 weeks in Southern Mexico from March 1995 to February 2007. We collected clinical and mycobacteriological information (isolation, identification, drug-susceptibility testing and IS6110-based genotyping and spoligotyping) from individuals with bacteriologically confirmed pulmonary tuberculosis. Patients were treated in accordance with official norms and followed to ascertain treatment outcomes, retreatment, and vital status.

RESULTS

eight hundred ninety-three tuberculosis patients were older than 15 years of age; of these, 147 (16.5%) were 65 years of age or older. Individuals ≥ 65 years had significantly higher rates of recently transmitted and reactivated tuberculosis. Older age was associated with treatment failure (OR=5.37; 95% CI: 1.06-27.23; P=0.042), and death due to tuberculosis (HR=3.52; 95% CI: 1.78-6.96; P<0.001) adjusting for sociodemographic and clinical variables.

CONCLUSIONS

community-dwelling older individuals participate in chains of transmission indicating that tuberculosis is not solely due to the reactivation of latent disease. Untimely and difficult diagnosis and a higher risk of poor outcomes even after treatment completion emphasise the need for specific strategies for this vulnerable group.

Geriatric drug therapy: neglecting the inevitable majority

Demographic evolution will considerably increase the number of people aged 65 years and beyond in the coming decades. The elderly not only represent the most heterogeneous population, but also are a major user group for prescribed medicines, a predominance that will continue to further increase. Medicines and medication management are much more complex and challenging in the elderly and can only be addressed through a multidisciplinary approach. There is strong evidence that the elderly are able to properly manage their medication; however, their medications require different features than the standard medications used by adults. The elderly are exposed to several chronic disease conditions and their treatments, as well as experience age-related changes and limitations that need to be reflected in their medication management strategies. Geriatric drug therapy remains a multidisciplinary task. The health care industry, physicians, pharmacists, nurses and care givers provide and guide the patient's therapy according to individual needs, while the health care system and regulatory authorities build the necessary framework of support and resources.Any realistic and significant enhancement to the elderly patients' medicines and medication management needs to be addressed by all disciplines and stakeholders involved since the absence of any of the stakeholders in the overall process negatively impacts the achievable enhancement in geriatric drug therapy.

Treatment of epilepsy in postmenopausal women

Menopausal women represent a rapidly growing proportion of the population. Epidemiologic evidence for the increased incidence of epilepsy in elderly patients suggests that with global aging of the population, there is likely to be a growing need for healthcare workers to manage seizures in older women. Unfortunately, there has been relatively little scientific investigation into the unique concerns of postmenopausal woman with epilepsy. There is some evidence that women may experience increased seizure activity during the menopausal transition owing to the effects of estrogen and progesterone on neuronal excitability. During perimenopause and menopause, use of hormone-replacement therapy can also worsen seizure control. Menopausal women are particularly vulnerable to osteoporosis and fragility fractures, both of which demonstrate increased risk following exposure to antiepileptic drugs. Optimization of epilepsy therapy to avoid both seizures and falls caused by antiepileptic drug-induced imbalance is crucial in order to minimize fracture risk in this group of women. Elderly patients are more susceptible to adverse medication side effects owing to drug interactions and the physiologic changes of aging that result in altered drug pharmacokinetics.

Bioequivalence of antiepileptic drugs: how close is close enough?

During the past few years, the use and substitution of generic antiepileptic drug products has been increasing both in the United States as well as globally. Although these less expensive products may represent an important alternative for many patients, there may be reasons for concern. Despite well-controlled regulatory studies, concerns persist regarding potential therapeutic inequivalence in some patients with epilepsy. These concerns have prompted some in the US neurology community as well as patient advocacy groups to question the current regulatory requirements for both establishing bioequivalence as well as product substitution. In addition, recent data have questioned the actual cost savings associated with generic substitution in this unique patient population. This article reviews current regulatory requirements and pharmacokinetic, biopharmaceutical, and clinical outcome issues that clinicians, pharmacists, and policymakers should consider regarding generic substitution of these complicated agents.

Topiramate in older patients with partial-onset seizures: a pilot double-blind, dose-comparison study

PURPOSE

Pharmacokinetics of antiepileptic drugs (AEDs) can be altered by age-related changes in physiology, thereby altering clinical effects, especially tolerability, in older adults. We compared two dosages of topiramate (TPM) in a pilot study of patients >or=60 years of age with partial-onset seizures.

METHODS

In this 24-week, double-blind, randomized, parallel-group study, patients with one or more seizures in previous 6 months were randomized to treatment with 50 or 200 mg/day TPM. TPM was initiated as monotherapy or added to one AED and titrated by 25 mg/day per week to target or maximum tolerated dose as the concomitant AED, if any, was withdrawn.

RESULTS

Thirty-eight patients were randomized to the 50 mg/day TPM (mean age, 68 years) and 39-200 mg/day TPM (69 years). Seizure control was similar with the two dosages when TPM could be used as monotherapy, whereas 200 mg TPM was more effective than 50 mg in patients requiring adjunctive therapy. The overall incidence of adverse events was similar for the two dosages--66% with 50 mg and 62% with 200 mg TPM. Most common adverse events were somnolence (TPM 50, 13%; TPM 200, 8%), dizziness (13% vs. 8%), and headache (13% vs. 5%). Of 10 (13%) patients reporting a cognitive-related adverse event, six patients were assigned to the 50-mg group. A total of 14 patients (18%; seven in each group) discontinued TPM due to adverse events.

CONCLUSIONS

This pilot study supports the practice of using low-to-moderate dosages of AEDs in older adults.

Epileptic fits and epilepsy in the elderly: general reflections, specific issues and therapeutic implications

Seizures and epilepsy are commonly encountered in the elderly. Diagnosis is not always straightforward as reliable history is often difficult to obtain and EEG findings can be non-specific. When to treat and how may be difficult choices as adequate studies in elderly are rather scarce. Treatment should be based on careful assessment and comparison of risk/benefit profiles of various anti-epileptic drugs (AEDs) in this specific elderly population. Since most AEDs are effective in terms of seizure control in the elderly, the choice of treatment is often determined by tolerability, pharmacokinetic profile and drug interactions of AEDs. As recently introduced AEDs have a better safety profile compared to older agents it seems logical to initiate treatment in the frail elderly patient with those more modern AEDs. In this review some distinctive clinical features of epilepsy in the elderly are discussed in three sections (general issues, special issues and selected treatment options with special reference to medicinal treatment).

Drug-nutrient interactions in elderly people

PURPOSE OF REVIEW

The presence of multiple diseases, polypharmacy, malnutrition, and impaired metabolism in elderly individuals increases the risks of adverse events related to drug-food interactions. Some considerations for elderly people influenced by drug-food interactions are reviewed.

RECENT FINDINGS

When investigating pharmacokinetic and pharmacodynamic modifications in the elderly, other factors have to be considered, such as anorexia, dementia, depression, intolerance, gastrointestinal-tract disorders, social and economic factors, reduced abilities (visual and manual) and difficulties in chewing or swallowing. Specific reference is made herein to the health status of the elderly Brazilian population based on the observations of our research group. In addition, the most common diseases (such as cancer, coronary heart disease, dementia, diabetes mellitus, hypertension and osteoporosis), the drugs usually prescribed to treat them, and the adverse nutritional reactions that occur in older patients are summarized.

SUMMARY

In order to develop a correct drug prescription plan and nutritional intervention to avoid any kind of undesirable drug-food interaction effect, it is necessary to adequately diagnose the disease and often re-evaluate the chosen treatment, identify disease stages and the necessary therapies to minimize the number of drugs administered, and select a reasonable nutritional assessment.

Epilepsy in the older patient

The world population is aging rapidly. The post World War II ‘baby boomers’ have benefited from improved medical science, sanitation, political freedom, and social and economic development, resulting in the knock-on demographic trend of an aging population. From a health-economic perspective, this places increasing demands on society and on health services to meet evolving medical and social needs. By 2025, over 30% of the populations of developed countries will be aged over 60 years (US Bureau of Census 2004).

Antiepileptic Drug Formulation and Treatment in the Elderly: Biopharmaceutical Considerations

The pharmacokinetics of antiepileptic drugs (AEDs) determine their effectiveness in the treatment of patients with epilepsy. Given the likelihood of comorbid medical conditions that require polytherapy, as well as the normal physiological changes associated with aging, an understanding of AED pharmacokinetics and pharmacodynamics in the elderly patient is critical. There is a relative sparsity of data regarding changes in the oral absorption patterns of AEDs that may accompany aging. Therefore, the objective of this chapter is to discuss fundamental principles related to oral drug absorption, and to discuss their potential impact on AED treatment in the older patient. Although most drugs are absorbed via the diffusion process, active transport also plays a role in absorption. While the gastrointestinal tract shows remarkable resilience during aging, physiological changes that influence oral and esophageal function, gastric pH, gastric emptying rates, and intestinal transit times do occur. Oral administration of AEDs may be affected by changes associated with aging, including altered oral protective reflexes, xerostomia, thickening of the esophageal smooth muscle layer, reduced contraction velocity and duration, altered esophageal emptying rates, and enteric plexus neuron reduction. Gastric acid secretion is similar between older and younger patients, but older patients require more time to return to baseline gastric pH values and have prolonged gastric emptying rates compared to younger patients. Elderly patients may similarly have reduced numbers of myenteric neurons, decreased postprandial contractions, reduced frequency of migrating motor complex, and diminished rectal compliance as well as reduced sphincter tones. All of these effects observed in the aging patient, in turn, produce numerous opportunities for changes in AED absorption, particularly for those agents demonstrating poor water solubility or variable absorption patterns.