Age‐Related Changes in Pharmacokinetics: Predictability and Assessment Methods

Spontaneous Spinal Hematoma in Patients Using Antiplatelets and Anticoagulants: A Systematic Review

BACKGROUND

Spontaneous spinal hematoma (SSH) is a debilitating complication in patients taking either antiplatelet (AP) or anticoagulation (AC) medications. SSH is rare and, therefore, a systematic review is warranted to re-examine and outline trends, clinical characteristics, and outcomes associated with SSH formation.

METHODS

PubMed, EMBASE, Scopus, and Web-of-Science were searched. Studies reporting clinical data of patients with SSH using AC medications were included. In addition, clinical studies meeting our a priori inclusion criteria limited to SSH were further defined in quality through risk bias assessment.

RESULTS

We included 10 studies with 259 patients' pooled data post-screening 3083 abstracts. Within the cohort (n = 259), the prevalence of idiopathic, nontraumatic SSH with concomitant treatment with AC medications was greater 191 (73.75%) compared with AP treatment (27%). The lumbar spine was the most common site of hematoma (41.70%), followed by the cervical (22.01%) and thoracic (8.49%) spine. Most patients had surgical intervention (70.27%), and 29.73% had conservative management. The pooled data suggest that immediate diagnosis and intervention are the best prognostic factors in clinical outcomes. American Spinal Injury Association grading at initial symptom onset and post-treatment showed the greatest efficacy in symptomatic relief (87.64%) and return of motor and sensory symptoms (39.19%).

CONCLUSIONS

Our review suggested that AC medications were related to SSH in most patients (74%), followed by APs (27%) and combined ACs + APs (1.9%). We recommend prompt intervention, a high suspicion for patients with neurologic deficits and diagnostic imaging before intervention to determine a case-specific treatment plan.

Recent advances in dosage form design for the elderly: a review

INTRODUCTION

With the increase in the elderly population and the prevalence of multiple medical conditions, medication adherence, and efficacy have become crucial for the effective management of their health. The aging population faces unique challenges that need to be addressed through advancements in drug delivery systems and formulation technologies.

AREAS COVERED

The current review highlights the recent advances in dosage form design for older individuals, with consideration of their specific physiological and cognitive changes. Various dosage forms, such as modified-release tablets/capsules, chewable tablets, and transdermal patches, can be tailored to meet the specific needs of elderly patients. Advancements in drug delivery systems, such as nanotherapeutics, additive manufacturing (three-dimensional printing), and drug-food combinations, improve drug delivery and efficacy and overcome challenges, such as dysphagia and medication adherence.

EXPERT OPINION

Regulatory guidelines and considerations are crucial in ensuring the safe utilization of medications among older adults. Important factors to consider include geriatric-specific guidelines, safety considerations, labeling requirements, clinical trial considerations, and adherence and accessibility considerations.

Pharmacological targeting of cognitive impairment in depression: recent developments and challenges in human clinical research

Impaired cognition is often overlooked in the clinical management of depression, despite its association with poor psychosocial functioning and reduced clinical engagement. There is an outstanding need for new treatments to address this unmet clinical need, highlighted by our consultations with individuals with lived experience of depression. Here we consider the evidence to support different pharmacological approaches for the treatment of impaired cognition in individuals with depression, including treatments that influence primary neurotransmission directly as well as novel targets such as neurosteroid modulation. We also consider potential methodological challenges in establishing a strong evidence base in this area, including the need to disentangle direct effects of treatment on cognition from more generalised symptomatic improvement and the identification of sensitive, reliable and objective measures of cognition.

Antiepileptic drugs patterns in elderly inpatients in a Brazilian tertiary center, Salvador, Brazil

Epilepsy is very prevalent among elderly inpatients and treatment is far from ideal. Objective To analyze prescribing patterns of antiepileptic drugs (AEDs) for hospitalized elderly with epilepsy, their relations with comorbidities and comedications. Method We assessed prescription regimen of elderly patients that were under AED use for treatment of epileptic seizures, during hospitalization. One hundred and nine patients were enrolled. AED regimen was categorized into two groups: Group 1 defined as appropriate (carbamazepine, oxcarbazepine, valproic acid, gabapentin, clobazan and lamotrigine) and Group 2 as inappropriate (phenytoin and phenobarbital). Results We found 73.4% of patients used inappropriate AEDs (p<0.001). Monotherapy was prescribed for 71.6% of patients. The most common comorbidity was hypertension. Potentially proconvulsant drugs as comedications were used for nearly half of patients. Conclusion Inappropriate AED therapy was commonly prescribed regimen for elderly inpatients. Some recommendations are discussed for a better care of elderly inpatients with epilepsy.

Pharmacokinetic of antiepileptic drugs in patients with hepatic or renal impairment

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

Individualization of drug therapy in older people

Older people are high consumers of prescription drugs and are at increasing risk of polypharmacy and adverse reactions. Pharmacokinetic and pharmacodynamic modifications due to age and co-morbidities are an important consideration, but pharmacological background evidence to guide safe and effective therapeutic approaches are often inadequate since the older population is under-represented in clinical trials. We review the pharmacokinetic and pharmacodynamic changes that are characteristic in old age and consider evidence regarding potentially safer prescription and monitoring of drugs commonly used in older patients. We also introduce the possible role of pharmacogenomics and therapeutic drug monitoring as tools to guide the individualization of drug therapy.

Epilepsy in the elderly: Special considerations and challenges

The elderly are generally defined as those over 60 or 65 years old, but they are a heterogeneous group and may be subdivided into categories based on age and health status. The incidence of epilepsy is highest in the elderly. With a progressive increase in life expectancy, this is the fastest growing segment of patients with epilepsy. Older patients most often have focal seizures, with less prominent auras and automatisms, and longer duration of postictal confusion compared to younger patients. Status epilepticus is common and has a high mortality. The most common specific etiology is cerebrovascular disease, but the cause remains unknown in many patients. Diagnosis can be challenging because of several patient-related, physician-related and investigation-related factors. Over-diagnosis and under-diagnosis are common. Treatment is complicated by the presence of physiological changes related to aging, co-morbidities and cognitive problems as well as concerns regarding drug interactions and medication adherence. Seizures can be controlled in most patients with low doses of a single anti-epileptic drug (AED). Tolerability is an important factor in selection of an AED, as elderly patients tend to be highly sensitive to side effects. Drug-resistant epilepsy is uncommon. Epilepsy surgery, especially temporal lobectomy, can be performed in older patients with good results. More studies addressing the pathophysiological mechanisms of epilepsy in this age group, and greater inclusion of the elderly in clinical trials, as well as development of comprehensive care models are needed to provide optimal care to these patients.

Clinical pharmacokinetics of new-generation antiepileptic drugs at the extremes of age: an update

Epilepsies occur across the entire age range, and their incidence peaks in the first years of life and in the elderly. Therefore, antiepileptic drugs (AEDs) are commonly used at the extremes of age. Rational prescribing in these age groups requires not only an understanding of the drugs' pharmacodynamic properties, but also careful consideration of potential age-related changes in their pharmacokinetic profile. The present article, which updates a review published in 2006 in this journal, focuses on recent findings on the pharmacokinetics of new-generation AEDs in neonates, infants, children, and the elderly. Significant new information on the pharmacokinetics of new AEDs in the perinatal period has been acquired, particularly for lamotrigine and levetiracetam. As a result of slow maturation of the enzymes involved in glucuronide conjugation, lamotrigine elimination occurs at a particularly slow rate in neonates, and becomes gradually more efficient during the first months of life. In the case of levetiracetam, elimination occurs primarily by renal excretion and is also slow at birth, but drug clearance increases rapidly thereafter and can even double within 1 week. In general, infants older than 2-3 months and children show higher drug clearance (normalized for body weight) than adults. This pattern was confirmed in recent studies that investigated the pediatric pharmacokinetics of several new AEDs, including levetiracetam, rufinamide, stiripentol, and eslicarbazepine acetate. At the other extreme of age, in the elderly, drug clearance is generally reduced compared with younger adults because of less efficient drug-metabolizing activity, decreased renal function, or both. This general pattern, described previously for several AEDs, was confirmed in recent studies on the effect of old age on the clearance of felbamate, levetiracetam, pregabalin, lacosamide, and retigabine. For those drugs which are predominantly eliminated by renal excretion, aging-related pharmacokinetic changes could be predicted by measuring creatinine clearance (CLCR). Overall, most recent findings confirm that age is a major factor influencing the pharmacokinetic profile of AEDs. However, pharmacokinetic variability at any age can be considerable, and the importance of other factors should not be disregarded. These include genetic factors, co-morbidities, and drug interactions, particularly those caused by concomitantly administered AEDs which induce or inhibit drug-metabolizing enzymes.

Apparent clearance of valproic acid in elderly epileptic patients: estimation of the confounding effect of albumin concentration

BACKGROUND

Valproic acid (VPA) apparent clearance (CL) estimated from total serum concentrations is analogous in elderly and non-elderly adult patients. As drug-protein binding decreases in old age, the aim of our study was to evaluate the confounding effect of the serum albumin concentration on the VPA apparent CL in elderly patients.

METHODS

In 102 epileptic out-patients treated with VPA in monotherapy, serum total steady-state trough concentrations (Css) were determined. Css concentrations were normalized for a 42 g/L albumin concentration (Css(N)), and the apparent CL and normalized apparent CL(N) were calculated.

RESULTS

A poor concordance of 53% was found in the classification of Css and Css(N) levels of VPA as subtherapeutic, therapeutic, or supratherapeutic dose. In the elderly (≥65 years) and non-elderly adult patients, the VPA apparent CL was similar; however, normalized apparent CL(N) was significantly lower in older patients (P < 0.01), with a 40% median decrease.

CONCLUSIONS

Total VPA concentrations should be interpreted with caution, mainly in older patients, in which determination of unbound or normalized total drug concentrations may be clinically useful. Normalization of total concentrations permits an estimation of the masking effect of serum albumin concentrations on the VPA apparent CL in elderly patients.

Development and validation of an analytical method based on high performance thin layer chromatography for the simultaneous determination of lamotrigine, zonisamide and levetiracetam in human plasma

Methods based on HPLC technology are the most frequently adopted for monitoring blood levels of novel antiepileptics. Here a rapid method based on HPTLC was developed for quantitative determination of lamotrigine (LTG), zonisamide (ZNS) and levetiracetam (LVT) in human plasma and compared with HPLC and LC-MS/MS methods. Chromatographic separation was achieved on silical gel 60F(254) plates using ethylacetate:methanol:ammonia (91:10:15v/v/v) as mobile phase. Quantitative analysis was carried out by densitometry at a wavelength of 312, 240 and 210nm for LTG, ZNS and LVT, respectively. Calibration curves were linear over range of 0-200ng for LTG and ZNS and 0-400ng for and LVT. The limit of quantification of LTG, ZNS and LTV was found to be 3.69, 3.7 and 6.85μg/ml, respectively. Intra and inter-assay precision provided relative standard deviations lower than 10% for all three analytes. Correlation and Bland-Altman plot showed general agreement between HPTLC and LC-MS/MS quantification, with a mean bias of -0.25, -0.46 and 0.5μg/ml for LTG ZNS and LVT, respectively. Likewise, comparison between HPLC-UV and LC-MS/MS showed good agreement for all the three compounds analyzed. In conclusion, the proposed HPTLC method is simple, rapid, precise and accurate. It therefore is appropriate for the routine quantification of therapeutic levels of LTG, ZNS and LVT in human plasma.

Review on pharmacokinetics and pharmacodynamics and the aging kidney

In people who are aged >65 years, pharmacokinetics are influenced more by the loss of kidney function than by the aging process of any other organ. A GFR of 30 to 60 ml/min, suggestive of stage 3 kidney disease, is observed in 15 to 30% of elderly people. Drug dosing must be adjusted to both changing pharmacokinetics and pharmacodynamics; the pharmacodynamics might be influenced by the aging of other organs, too. Using our NEPharm database, we extracted abstracts with pharmacokinetic parameters since 1999 from a weekly PubMed search. The recorded data were analyzed and compared with published recommendations on drug dosage and use in the elderly. Purely age-related changes in pharmacokinetic parameters were recorded from publications on 127 drugs. The analysis of our NEPharm records revealed an average (mean +/- SD) age-related prolongation of half-life of 1.39-fold (corresponding to +39 +/- 61%). Contrasting to common opinion, mean changes in clearance (-1 +/- 54%) and volume of distribution (+24 +/- 56%) were even less. The modest changes in pharmacokinetics do not suggest general dosage modifications in the elderly for most drugs. Changes in pharmacodynamics justify the common medication rule in the elderly-"start low + go slow"-especially for drugs that act on the central nervous system; however, in the case of anti-infective and anticancer therapy, the rule should be "hit hard = start high + go fast" to produce the target effect also in the elderly.

The International Society for Bipolar Disorders (ISBD) consensus guidelines for the safety monitoring of bipolar disorder treatments

OBJECTIVES

Safety monitoring is an important aspect of bipolar disorder treatment, as mood-stabilising medications have potentially serious side effects, some of which may also aggravate existing medical comorbidities. This paper sets out the International Society for Bipolar Disorders (ISBD) guidelines for the safety monitoring of widely used agents in the treatment of bipolar disorder. These guidelines aim to provide recommendations that take into consideration the balance between safety and cost-effectiveness, to highlight iatrogenic and preventive clinical issues, and to facilitate the broad implementation of therapeutic safety monitoring as a standard component of treatment for bipolar disorder.

METHODS

These guidelines were developed by an ISBD workgroup, headed by the senior author (MB), through an iterative process of serial consensus-based revisions. After this, feedback from a multidisciplinary group of health professionals on the applicability of these guidelines was sought to develop the final recommendations.

RESULTS

General safety monitoring recommendations for all bipolar disorder patients receiving treatment and specific monitoring recommendations for individual agents are outlined.

CONCLUSIONS

These guidelines are derived from evolving and often indirect data, with minimal empirical cost-effectiveness data available to provide guidance. These guidelines will therefore need to be modified to adapt to different clinical settings and health resources. Clinical acumen and vigilance remain critical ingredients for safe treatment practice.