The elderly—a challenge for appropriate drug treatment

Is Therapeutic Drug Monitoring of Lacosamide Needed in Patients with Seizures and Epilepsy?

Lacosamide is an antiepileptic drug (AED) that has linear pharmacokinetics, predictable blood concentrations, and few drug interactions, setting it apart from other AEDs that require vigorous therapeutic drug monitoring (TDM) such as phenytoin and carbamazepine. However, there have been reports of altered lacosamide pharmacokinetics in some populations. The purpose of this review is to determine whether lacosamide pharmacokinetics are altered in certain patient populations, suggesting the need for TDM. A literature search of Medline, Scopus, Embase, and Cochrane trials was conducted on January 3, 2019 (and then updated on September 2, 2019) to search for articles relevant to the TDM or pharmacokinetics of lacosamide. A total of 56 relevant articles were found and included in this review. Dose of lacosamide is linearly correlated with plasma concentrations and efficacy. However, currently there is no well-established reference range. Overall, the recommended reference ranges varied from 2.2 to 20 mg/L. Lacosamide has very few clinically relevant drug-drug interactions; however, there seems to be a significant drug interaction between lacosamide and enzyme-inducer AEDs. Based on available literature, it appears that lacosamide pharmacokinetics may be altered in severe renal dysfunction, in patients on dialysis and with extremes of age. More evidence is currently needed on lacosamide pharmacokinetics in pregnancy and critical illness. While it is not practical to utilize TDM for all patients, TDM may be useful in patients taking enzyme-inducer AEDs, in patients with decreased renal function or on dialysis, and older adults.

Willingness to Change Medications Linked to Increased Fall Risk: A Comparison between Age Groups

OBJECTIVE

To describe and compare two age groups' knowledge of medications linked to falls and willingness to change these medications to reduce their fall risk.

METHOD

We analyzed data from community-dwelling adults age 55 and older (n = 1812): 855 adults aged 55 to 64 years and 957 older adults (65 and older) who participated in the 2016 summer wave of the ConsumerStyles survey, an annual Web-based survey. The data are weighted to match the US Current Population Survey proportions on nine US Census Bureau demographic characteristics.

MEASUREMENTS

Survey respondents were asked about medication use, knowledge of side effects, their willingness to change their medications to reduce fall risk, communication in the previous year about fall risk with their healthcare provider, and their comfort in discussing fall risk with their healthcare provider. All data were weighted to match the 2016 population estimates. Descriptive statistics and χ² (p ≤ .05) were used to identify differences between the two age groups.

RESULTS

About one-fifth of all respondents reported using at least one class of medication that increases fall risk. Older adults were less likely to report using medications for mood or sadness, less likely to report knowing the side effects of pain medications, and more willing to change their sleep medications compared with their younger counterparts. Among all respondents using these medication classes, less than one-third knew the potential fall-related side effects. However, most of them expressed willingness to change their medication if advised by their healthcare provider.

CONCLUSION

Most older adults were unaware of potential fall risks associated with medications prescribed to address pain, difficulty sleeping, mood or sadness, and anxiety- or nervousness-related health issues. However, most were willing to change their medication if recommended by a healthcare provider. J Am Geriatr Soc 67:527-533, 2019.

3D-Printed Network Structures as Controlled-Release Drug Delivery Systems: Dose Adjustment, API Release Analysis and Prediction

3D printing evolved as a promising technique to improve individualization of drug therapy. In particular, when printing sustained release solid dosage forms, as for instance implants, inserts, and also tablets, estimation of the drug release profile in vivo is necessary. In most cases, corresponding analyses cannot be performed at hospital or community pharmacies. Therefore, the present study aimed to develop a sustained release drug delivery system produced via 3D printing, which allows dose adaption and estimation of drug release at the same time. Filaments as feedstock for the printer were produced via hot-melt extrusion and consisted of Eudragit® RL as sustained release polymer, 30% theophylline as model active pharmaceutical ingredient, and stearic acid as solid plasticizer. Assuming that the surface/mass ratio was constant, network structures of different densities were printed as novel solid dosage form. Their weight (263 to 668 mg), thereby their dose, and surface area, determined using X-ray microcomputed tomography, showed a linear correlation with the fill density. The specific surface area of the network hardly varied with changing fill density. Dissolution studies showed a slower drug release for dosage forms with a denser network. Higuchi's model was used for prediction of drug release and showed limited applicability due to different release kinetics for different fill densities. However, using linear interpolation for the prediction resulted in good RMSEP values between 1.4 and 3.7%. These findings might be useful to enable customized production of sustained release solid dosage forms via 3D printing in hospital and community pharmacies in the future.

Potentially Inappropriate Prescribing in Older Patients Discharged From Acute Care Hospitals to Residential Aged Care Facilities

Background: The frequency of prescribing potentially inappropriate medications (PIMs) in older patients remains high despite evidence of adverse outcomes from their use. Little is known about whether admission to hospital has any effect on appropriateness of prescribing. Objectives: This study aimed to identify the prevalence and nature of PIMs and explore the association of risk factors for receiving a PIM. Methods: This was a prospective study of 206 patients discharged to residential aged care facilities from acute care. All patients were at least 70 years old and were admitted between July 2005 and May 2010; their admission and discharge medications were evaluated. Results: Mean patient age was 84.8 ± 6.7 years; the majority (57%) were older than 85 years, and mean (SD) Frailty Index was 0.42 (0.15). At least 1 PIM was identified in 112 (54.4%) patients on admission and 102 (49.5%) patients on discharge. Of all medications prescribed at admission (1728), 10.8% were PIMs, and at discharge, of 1759 medications, 9.6% were PIMs. Of the total 187 PIMs on admission, 56 (30%) were stopped and 131 were continued; 32 new PIMs were introduced. Of the potential risk factors considered, in-hospital cognitive decline and frailty status were the only significant predictors of PIMs. Conclusions: Although admission to hospital is an opportunity to review the indications for specific medications, a high prevalence of inappropriate drug use was observed. The only associations with PIM use were the frailty status and in-hospital cognitive decline. Additional studies are needed to further evaluate this association.

Discovery of Multi-Target Agents for Neurological Diseases via Ligand Design

The incidence of neurological disorders in the developed world is rising in concert with an increase in human life expectancy, due in large part to better nutrition and health care. Even as drug discovery efforts are refocused on these disorders, there has been a dearth in the introduction of new disease-modifying therapies to prevent or delay their onset, or reverse their progression. Mounting evidence points to complex and heterogeneous etiopathologies that underlie these diseases. Therefore, it is unlikely that disorders in this class will be mitigated by any single drug that acts exclusively on a single pathway or target. The rational design of novel drug entities with the ability to simultaneously address multiple drug targets of a complex pathophysiology has recently emerged as a new paradigm in drug discovery. Similarly to the concept of multi-target agents within the psychopharmacology field, ligand design has gained an increasing prominence within the medicinal chemistry community. In this chapter we discuss several examples of select chemical scaffolds (polyamines, alkylxanthines, and propargyl carbamates) wherein these concepts were applied to develop novel drug candidates for Alzheimer's disease and Parkinson's disease.

Pharmacoeconomics and aging

The aging of the general population in industrialized countries has brought to public attention the increasing incidence of age-related clinical conditions, because the long-term impact of diseases on functional status and on costs are greater in older people than in any other age group. With the aging of the population, it is becoming increasingly important to quantify the burden of illness in the elderly; this will be vital not only in planning for the necessary health services that will be required in coming years, but also in order to measure the benefit to be expected from interventions to prevent disability in older people. The management of multiple and chronic disorders has become a more important issue for healthcare authorities because of increasing requests for medical assistance and healthcare interventions. Among these, pharmacological treatments and drug utilization in older people are pressing issues for healthcare managers and politicians; indeed, a relatively small proportion of the population accounts for a substantial part of public drug costs. Two key sources of pressure are well known: the growing number of elderly persons, who are the highest per-capita users of medicines, and the introduction of new, often more expensive, medicines. On the other hand, the development of strategies for controlling costs, while providing the elderly with equitable access to needed pharmaceuticals, should be based on an evaluation of the economic impact of pharmacological care in older people, taking into account the burden of illness, drug utilization data, drug technology assessment evidence and results. Furthermore, there are major factors affecting pharmacological care in older people: for example inappropriate prescribing, lack of adherence and compliance, and the burden of adverse drug events. The assessment of these factors should be considered a priority in pharmacoeconomic evaluations in the aging population, and the most relevant evidence will be reviewed in this paper with examples referring to particular settings or conditions and diseases, such as the presence of cardiovascular risk factors, diabetes and chronic pain.

Pharmacokinetics and drug metabolism in the elderly

Aging involves progressive impairments in the functional reserve of multiple organs, which might also affect drug metabolism and pharmacokinetics. In addition, the elderly population will develop multiple diseases and, consequently, often has to take several drugs. As the hepatic first-pass effect of highly cleared drugs could be reduced (due to decreases in liver mass and perfusion), the bioavailability of some drugs can be increased in the elderly. Significant changes in body composition occur with advancing age. Lipophilic drugs may have an increased volume of distribution (Vd) with a prolonged half-life, and water-soluble drugs tend to have a smaller Vd. In the elderly, hepatic drug clearance of some drugs can be reduced by up to 30% and CYP-mediated phase I reactions are more likely to be impaired than phase II metabolism, which is relatively preserved in the elderly. Concerning the most important CYP3A4 studies with human liver microsomes and clinical studies with the validated probe, midazolam, it is indicated that there are no significant differences in CYP3A4 activity between young and old populations. Finally, renal excretion is decreased (up to 50%) in about two thirds of elderly subjects, but confounding factors such as hypertension and coronary heart disease account also for a decline in kidney function. In conclusion, age-related physiological and pharmacokinetic changes as well as the presence of comorbidity and polypharmacy will complicate drug therapy in the elderly.