Drug metabolism in older people--a key consideration in achieving optimal outcomes with medicines

Population pharmacokinetics of Ainuovirine and exposure-response analysis in human immunodeficiency virus-infected individuals

BACKGROUND

Ainuovirine (ANV) is a new generation of non-nucleoside reverse transcriptase inhibitor for the treatment of human immunodeficiency virus (HIV) type 1 infection. This study aimed to evaluate the population pharmacokinetic (PopPK) profile and exposure-response relationship of ANV among people living with HIV.

METHODS

Plasma concentration-time data from phase 1 and phase 3 clinical trials of ANV were pooled for developing the PopPK model. Exposure estimates obtained from the final model were used in exposure-response analysis for virologic responses and safety responses.

RESULTS

ANV exhibited a nonlinear pharmacokinetic profile, which was best described by a two-compartment model with first-order elimination. There were no significant covariates correlated to the pharmacokinetic parameters of ANV. The PopPK parameter estimate (relative standard error [%]) for CL/F was 6.46 (15.00) L/h, and the clearance of ANV increased after multiple doses. The exposure-response model revealed no significant correlation between the virologic response (HIV-RNA <50 copies/mL) at 48 weeks and the exposure, but the incidence of adverse events increased with the increasing exposure( P value of steady-state trough concentration and area under the steady-state curve were 0.0177 and 0.0141, respectively).

CONCLUSIONS

Our PopPK model supported ANV 150 mg once daily as the recommended dose for people living with HIV, requiring no dose adjustment for the studied factors. Optimization of ANV dose may be warranted in clinical practice due to an increasing trend in adverse reactions with increasing exposure.

TRIAL REGISTRATION

Chinese Clinical Trial Registry https://www.chictr.org.cn (Nos. ChiCTR1800018022 and ChiCTR1800019041).

Sex, race, and BMI in clinical trials of medications for obesity over the past three decades: a systematic review

Medications for obesity have been studied in various populations over the past three decades. We aimed to quantify the baseline demographic characteristics of BMI, sex, age, and race in randomised clinical trials (RCTs) across three decades to establish whether the population studied is representative of the global population affected by the disease. Clinical trials of 12 medications for obesity (ie, orlistat, naltrexone-bupropion, topiramate-phentermine, liraglutide, semaglutide, lorcaserin, sibutramine, rimonabant, taranabant, tirzepatide, retatrutide, and orforglipron) published from Jan 20, 1999, to Nov 12, 2023, were assessed through a systematic review for methodological quality and baseline demographic characteristics. 246 RCTs were included, involving 139 566 participants with or without type 2 diabetes. Most trials over-recruited White, female participants aged 40 years or older with class 1 (30·0-34·9 kg/m2) and class 2 (35·0-39·9 kg/m2) obesity; older participants, those with class 3 (≥40·0 kg/m2) obesity, non-White participants, and male participants were under-recruited. Our systematic review suggests that future trials need to recruit traditionally under-represented populations to allow for accurate measures of efficacy of medications for obesity, enabling more informed decisions by clinicians. It is also hoped that these data will help to refine trial recruitment strategies to ensure that future studies are relevant to the population affected by obesity.

Exploring clozapine pharmacokinetics in Tunisian schizophrenic patients: A population-based modelling approach investigating the impact of genetic and non-genetic variables

Clozapine is characterized by a large within- and between-patient variability in its pharmacokinetics, attributed to non-genetic and genetic factors. A cross-sectional analysis of clozapine trough concentration (Clz C0) issued from Tunisian schizophrenic patients was collected and analysed using a nonparametric modelling approach. We assessed the impact of demographic covariates (age, weight and sex), patient's habits (smoking status, alcohol and caffeine intake) and the genetic factors (CYP1A2*1C, CYP1A2*1F and CYP2C19*2 polymorphisms) on each pharmacokinetic parameter. An external validation of this pharmacokinetic model using an independent data set was performed. Fit goodness between observed- and individual-predicted data was evaluated using the mean prediction error (% MPE), the mean absolute prediction error (% MAPE) as a measure of bias, and the root mean squared error (% RMSE) as a measure of precision. Sixty-three CLz C0 values issued from 51 schizophrenic patients were assessed in this study and divided into building and validation groups. CYP1A2*1F polymorphism and smoking status were the only covariates significantly associated with clozapine clearance. Precision parameters were as follows: 1.02%, 0.95% and 22.4%, respectively, for % MPE, % MAPE and % RMSE. We developed and validated an accurate pharmacokinetic model able to predict Clz C0 in Tunisian schizophrenic patients using the two parameters CYP1A2*1F polymorphism and smoking.

A population pharmacokinetic model to guide clozapine dose selection, based on age, sex, ethnicity, body weight and smoking status

AIMS

Guidance on clozapine dosing in treatment-resistant schizophrenia is based largely on data from White young adult males. This study aimed to investigate the pharmacokinetic profiles of clozapine and N-desmethylclozapine (norclozapine) across the age range, accounting for sex, ethnicity, smoking status and body weight.

METHODS

A population pharmacokinetic model, implemented in Monolix, that linked plasma clozapine and norclozapine via a metabolic rate constant, was used to analyse data from a clozapine therapeutic drug monitoring service, 1993-2017.

RESULTS

There were 17 787 measurements from 5960 patients (4315 male) aged 18-86 years. The estimated clozapine plasma clearance was reduced from 20.2 to 12.0 L h-1 between 20 and 80 years. Model-based dose predictions to attain a predose plasma clozapine concentration of 0.35 mg L-1 was 275 (90% prediction interval 125, 625) mg day-1 in nonsmoking, White males weighing 70 kg and aged 40 years. The corresponding predicted dose was increased by 30% in smokers, decreased by 18% in females, and was 10% higher and 14% lower in otherwise analogous Afro-Caribbean and Asian patients, respectively. Overall, the predicted dose decreased by 56% between 20 and 80 years.

CONCLUSION

The large sample size and wide age range of the patients studied allowed precise estimation of dose requirements to attain predose clozapine concentration of 0.35 mg L-1 . The analysis was, however, limited by the absence of data on clinical outcome and future studies are required to determine optimal predose concentrations specifically in those aged over 65 years.

Epigenetic regulation of drug metabolism in aging: utilizing epigenetics to optimize geriatric pharmacotherapy

We explore the relationship between epigenetic aging and drug metabolism. We review current evidence for changes in drug metabolism in normal aging, followed by a description of how epigenetic modifications associated with age can regulate the expression and functionality of genes. In particular, we focus on the role of epigenome-wide studies of human and mouse liver in understanding these age-related processes with respect to xenobiotic processing. We highlight genes encoding drug metabolizing enzymes and transporters revealed to be affected by epigenetic aging in these studies. We conclude that substantial evidence exists for epigenetic aging impacting drug metabolism and transport genes, but more work is needed. We further highlight the promise of pharmacoepigenetics applied to enhancing drug safety in older adults.

Innovations, Opportunities, and Challenges for Predicting Alteration in Drug-Metabolizing Enzyme and Transporter Activity in Specific Populations

Drug-metabolizing enzymes and transporters (DMETs) are key regulators of the pharmacokinetics, efficacy, and toxicity of therapeutics. Over the past two decades, significant advancements in in vitro methodologies, targeted proteomics, in vitro to in vivo extrapolation methods, and integrated computational approaches such as physiologically based pharmacokinetic modeling have unequivocally contributed to improving our ability to quantitatively predict the role of DMETs in absorption, distribution, metabolism, and excretion and drug-drug interactions. However, the paucity of data regarding alterations in DMET activity in specific populations such as pregnant individuals, lactation, pediatrics, geriatrics, organ impairment, and disease states such as, cancer, kidney, and liver diseases and inflammation has restricted our ability to realize the full potential of these recent advancements. We envision that a series of carefully curated articles in a special supplementary issue of Drug Metabolism and Disposition will summarize the latest progress in in silico, in vitro, and in vivo approaches to characterize alteration in DMET activity and quantitatively predict drug disposition in specific populations. In addition, the supplementary issue will underscore the current scientific knowledge gaps that present formidable barriers to fully understand the clinical implications of altered DMET activity in specific populations and highlight opportunities for multistakeholder collaboration to advance our collective understanding of this rapidly emerging area. SIGNIFICANCE STATEMENT: This commentary highlights current knowledge and identifies gaps and key challenges in understanding the role of drug-metabolizing enzymes and transporters (DMETs) in drug disposition in specific populations. With this commentary for the special issue in Drug Metabolism and Disposition, the authors intend to increase interest and invite potential contributors whose research is focused or has aided in expanding the understanding around the role and impact of DMETs in drug disposition in specific populations.

CYP1A2 expression rather than genotype is associated with olanzapine concentration in psychiatric patients

Olanzapine is a commonly prescribed atypical antipsychotic agent for treatment of patients with schizophrenia and bipolar disorders. Previous in vitro studies using human liver microsomes identified CYP1A2 and CYP2D6 enzymes being responsible for CYP-mediated metabolism of olanzapine. The present work focused on the impact of CYP1A2 and CYP2D6 genetic polymorphisms as well as of CYP1A2 metabolizing capacity influenced by non-genetic factors (sex, age, smoking) on olanzapine blood concentration in patients with psychiatric disorders (N = 139). CYP2D6 genotype-based phenotype appeared to have negligible contribution to olanzapine metabolism, whereas a dominant role of CYP1A2 in olanzapine exposure was confirmed. However, CYP1A2 expression rather than CYP1A2 genetic variability was demonstrated to be associated with olanzapine concentration in patients. Significant contribution of - 163C > A (rs762551), the most common SNP (single nucleotide polymorphism) in CYP1A2 gene, to enhanced inducibility was confirmed by an increase in CYP1A2 mRNA expression in smokers carrying - 163A, and smoking was found to have appreciable impact on olanzapine concentration normalized by the dose/bodyweight. Furthermore, patients' olanzapine exposure was in strong association with CYP1A2 expression; therefore, assaying CYP1A2 mRNA level in leukocytes can be an appropriate tool for the estimation of patients' olanzapine metabolizing capacity and may be relevant in optimizing olanzapine dosage.

Development of population pharmacokinetics model and Bayesian estimation of rifampicin exposure in Indonesian patients with tuberculosis

BACKGROUND

Interindividual variability in the pharmacokinetics (PK) of anti-tuberculosis (TB) drugs is the leading cause of treatment failure. Herein, we evaluated the influence of demographic, clinical, and genetic factors that cause variability in RIF PK parameters in Indonesian TB patients.

METHODS

In total, 210 Indonesian patients with TB (300 plasma samples) were enrolled in this study. Clinical data, solute carrier organic anion transporter family member-1B1 (SLCO1B1) haplotypes *1a, *1b, and *15, and RIF concentrations were analyzed. The population PK model was developed using a non-linear mixed effect method.

RESULTS

A one-compartment model with allometric scaling adequately described the PK of RIF. Age and SLCO1B1 haplotype *15 were significantly associated with variability in apparent clearance (CL/F). For patients in their 40s, each 10-year increase in age was associated with a 10% decrease in CL/F (7.85 L/h). Patients with the SLCO1B1 haplotype *15 had a 24% lower CL/F compared to those with the wild-type. Visual predictive checks and non-parametric bootstrap analysis indicated good model performance.

CONCLUSION

Age and SLCO1B1 haplotype *15 were significant covariates of RIF CL/F. Geriatric patients with haplotype *15 had significantly greater exposure to RIF. The model could optimize TB pharmacotherapy through its application in therapeutic drug monitoring (clinical trial no. NCT05280886).

Hepatotoxicity with High-Dose Green Tea Extract: Effect of Catechol-O-Methyltransferase and Uridine 5'-Diphospho-glucuronosyltransferase 1A4 Genotypes

The predominant catechin in green tea, epigallocatechin gallate (EGCG), may be hepatotoxic in high doses. Our objective was to investigate the influence of catechol-O-methyltransferase (COMT) and uridine 5'-diphospho-glucuronosyltransferase 1A4 (UGT1A4) genotypes on changes in liver injury biomarkers in response to long-term, high-dose green tea extract (GTE) supplementation among postmenopausal women. A secondary analysis was conducted using data from the Minnesota Green Tea Trial (N = 1,075), in which participants were randomized to consume high-dose GTE (843 mg/day EGCG) or placebo capsules for 12 months. Analysis of covariance adjusting for potential confounders was performed to examine changes in aspartate aminotransferase (AST), alanine aminotransferase (ALT), AST: ALT ratio, and alkaline phosphatase from baseline to months 3, 6, 9, and 12 across COMT and UGT1A4 genotypes. Mean age and BMI within the GTE group (n = 400) were 59.8 yrs and 25.1 kg/m2, respectively, and 98% of subjects were white. From baseline to month 3, mean AST: ALT ratio change was +1.0% in the COMT (rs4680) A/G genotype versus -4.8% in the A/A genotype (p = 0.03). From baseline to months 6 and 9, respectively, mean ALT change was +78.1% and +82.1% in the UGT1A4 (rs6755571) A/C genotype versus +28.0% and +30.1% in the C/C genotype (p < 0.001 and p = 0.004, respectively). The UGT1A4 (rs6755571) A/C genotype may be an important risk factor for clinically-relevant serum transaminase elevations with 6-9 months of high-dose GTE supplementation among postmenopausal women. Understanding the genetic underpinnings of GTE-related hepatotoxicity may allow for a genetically-informed paradigm for therapeutic use of GTE.

A Risk-Factor Model for Antineoplastic Drug-Induced Serious Adverse Events in Cancer Inpatients: A Retrospective Study Based on the Global Trigger Tool and Machine Learning

The objective of this study was to apply a machine learning method to evaluate the risk factors associated with serious adverse events (SAEs) and predict the occurrence of SAEs in cancer inpatients using antineoplastic drugs. A retrospective review of the medical records of 499 patients diagnosed with cancer admitted between January 1 and December 31, 2017, was performed. First, the Global Trigger Tool (GTT) was used to actively monitor adverse drug events (ADEs) and SAEs caused by antineoplastic drugs and take the number of positive triggers as an intermediate variable. Subsequently, risk factors with statistical significance were selected by univariate analysis and least absolute shrinkage and selection operator (LASSO) analysis. Finally, using the risk factors after the LASSO analysis as covariates, a nomogram based on a logistic model, extreme gradient boosting (XGBoost), categorical boosting (CatBoost), adaptive boosting (AdaBoost), light-gradient-boosting machine (LightGBM), random forest (RF), gradient-boosting decision tree (GBDT), decision tree (DT), and ensemble model based on seven algorithms were used to establish the prediction models. A series of indicators such as the area under the ROC curve (AUROC) and the area under the PR curve (AUPR) was used to evaluate the model performance. A total of 94 SAE patients were identified in our samples. Risk factors of SAEs were the number of triggers, length of stay, age, number of combined drugs, ADEs occurred in previous chemotherapy, and sex. In the test cohort, a nomogram based on the logistic model owns the AUROC of 0.799 and owns the AUPR of 0.527. The GBDT has the best predicting abilities (AUROC = 0.832 and AUPR = 0.557) among the eight machine learning models and was better than the nomogram and was chosen to establish the prediction webpage. This study provides a novel method to accurately predict SAE occurrence in cancer inpatients.

Clinical standards for the dosing and management of TB drugs

BACKGROUND: Optimal drug dosing is important to ensure adequate response to treatment, prevent development of drug resistance and reduce drug toxicity. The aim of these clinical standards is to provide guidance on 'best practice´ for dosing and management of TB drugs.METHODS: A panel of 57 global experts in the fields of microbiology, pharmacology and TB care were identified; 51 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all participants.RESULTS: Six clinical standards were defined: Standard 1, defining the most appropriate initial dose for TB treatment; Standard 2, identifying patients who may be at risk of sub-optimal drug exposure; Standard 3, identifying patients at risk of developing drug-related toxicity and how best to manage this risk; Standard 4, identifying patients who can benefit from therapeutic drug monitoring (TDM); Standard 5, highlighting education and counselling that should be provided to people initiating TB treatment; and Standard 6, providing essential education for healthcare professionals. In addition, consensus research priorities were identified.CONCLUSION: This is the first consensus-based Clinical Standards for the dosing and management of TB drugs to guide clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment to improve patient care.

Population Pharmacokinetic Models for Direct Oral Anticoagulants: A Systematic Review and Clinical Appraisal Using Exposure Simulation

Available data have shown an association between direct oral anticoagulant (DOAC) plasma concentration and clinical, particularly bleeding, events. Factors that may influence DOAC plasma concentration are therefore the focus of particular attention. Population pharmacokinetic (PopPK) analyses can help in identifying such factors while providing predictive models. The main aim of the present study was to identify all the PopPK models to date for the four most frequently used DOACs (dabigatran, apixaban, rivaroxaban, and edoxaban). The secondary aim was to use these models to simulate different DOAC plasma concentration–time profiles in relevant clinical scenarios. The results of our model‐based simulations confirm the clinical relevance of the known major factors influencing DOAC exposure and support the current approved dose adaptation, at least for atrial fibrillation. They also highlight how the accumulation of covariates, not currently considered for dose adaptation due to their seemingly minor influence on DOAC exposure, lead to supratherapeutic blood concentrations and could thus enhance the risk of major bleeding. The present results therefore question DOAC dose adaptation in the presence of these covariates, such as drug–drug interaction or genotypes, alongside the known existing covariates. As the overall effect of accumulation of several covariates could be difficult to apprehend for the clinicians, PopPK modeling could represent an interesting approach for informed precision dosing and to improve personalized prescription of DOACs.

Hepatic drug metabolism in older people with body composition changes

AIM

Dosage adjustment is essential in older individuals because they are prone to experience a decline in liver function and changes in body composition. However, quantitative tests or equations for evaluating the activity of hepatic drug metabolism have not yet been clearly established. We examined hepatic drug metabolism activities in older individuals, focusing on changes in body composition parameters.

METHODS

Lansoprazole and nifedipine, substrates of the metabolic enzymes cytochrome P450 (CYP) 2C19 and 3A4, respectively, were selected to study hepatic drug metabolism. Residual samples from blood test for older patients were evaluated to determine drug metabolism. The body composition of relevant patients was determined by analyzing characteristic parameters of skeletal muscle mass index (SMI), handgrip strength (HGS) and hepatic steatosis index (HSI). The differences in hepatic drug metabolism were studied statistically among categories in terms of the cut-off value of these parameters.

RESULTS

Older male patients receiving lansoprazole and nifedipine in the low SMI (<7.0 kg/m² ) category showed an 85-90% reduction in respective CYP2C19 and CYP3A4 metabolic activities compared with the normal SMI category. For the female patients, CYP2C19 and CYP3A4 metabolic activities showed no significant correlation with SMI and HGS. Fatty liver disease (HSI ≥36) was found to reduce CYP2C19 metabolic activity particularly in older female patients.

CONCLUSIONS

Low CYP2C19 metabolic activity was statistically correlated with low SMI in male patients and high HSI in female patients, whereas low CYP3A4 metabolic activity was statistically correlated with low HGS in male patients. Geriatr Gerontol Int 2022; 22: 449-454.

Incidence, patterns, risk factors and clinical outcomes of intravenous acyclovir induced nephrotoxicity

Objectives

Acyclovir is approved to treat herpes simplex virus (HSV) type 1, type 2 and varicella-zoster virus. It is mainly eliminated via the kidneys, for which drug crystals accumulation might lead to nephrotoxicity. This study aimed to determine the incidence, risk factors, preventive measures, and clinical outcomes of acyclovir induced-nephrotoxicity.

Methods

This is a retrospective cohort study of patients >12 years of age at Sultan Qaboos University Hospital (SQUH) receiving IV acyclovir therapy between January 2016 and December 2020.

Results

Out of 191 included patients, 40 (20.1%) developed acyclovir induced-nephrotoxicity. Age (per year older: OR 1.04, 95 %CI 1.01–1.07), total duration of treatment (per day OR1.19, 95 %CI 1.06–1.33), and concomitant use of vancomycin (OR 5.96, 95 %CI 1.87–19.01) were significant independent risk factors for acyclovir induced-nephrotoxicity development. Nine patients (4.5%) died during the same hospitalization, including those three patients who required renal replacement therapy (1.5%).

Conclusion

Frequent monitoring of kidney function for older patients with concurrent use of vancomycin and IV hydration is essential to prevent IV acyclovir induced-nephrotoxicity. Antimicrobial stewardship is a crucial method to reduce the duration of treatment with IV acyclovir as appropriate.

Histone acetylation at the sulfotransferase 1a1 gene is associated with its hepatic expression in normal aging

OBJECTIVES

Phase II drug metabolism is poorly studied in advanced age and older adults may exhibit significant variability in their expression of phase II enzymes. We hypothesized that age-related changes to epigenetic regulation of genes involved in phase II drug metabolism may contribute to these effects.

METHODS

We examined published epigenome-wide studies of human blood and identified the SULT1A1 and UGT1A6 genes as the top loci showing epigenetic changes with age. To assess possible functional alterations with age in the liver, we assayed DNA methylation (5mC) and histone acetylation changes around the mouse homologs Sult1a1 and Ugt1a6 in liver tissue from mice aged 4-32 months.

RESULTS

Our sample shows a significant loss of 5mC at Sult1a1 (β = -1.08, 95% CI [-1.8, -0.2], SE = 0.38, P = 0.011), mirroring the loss of 5mC with age observed in human blood DNA at the same locus. We also detected increased histone 3 lysine 9 acetylation (H3K9ac) with age at Sult1a1 (β = 0.11, 95% CI [0.002, 0.22], SE = 0.05, P = 0.04), but no change to histone 3 lysine 27 acetylation (H3K27ac). Sult1a1 gene expression is significantly positively associated with H3K9ac levels, accounting for 23% of the variation in expression. We did not detect any significant effects at Ugt1a6.

CONCLUSIONS

Sult1a1 expression is under epigenetic influence in normal aging and this influence is more pronounced for H3K9ac than DNA methylation or H3K27ac in this study. More generally, our findings support the relevance of epigenetics in regulating key drug-metabolizing pathways. In the future, epigenetic biomarkers could prove useful to inform dosing in older adults.

Tuberculosis treatment incompletion in patients with lung cancer: occurrence and predictors

BACKGROUND

Lung cancer patients are high-risk for active tuberculosis (TB); however, fragility and drug-drug interaction might lead to TB treatment interruption. TB treatment incompletion occurrence and predictors among lung cancer patients remain unclear.

METHODS

We recruited lung cancer patients with new-onset TB from Taiwan Cancer Registry and Taiwanese National Health Insurance 2007-2015 databases. TB treatment incompletion was the identified primary outcome, and associated risk factors were analyzed.

RESULTS

A total of 1155 lung cancer patients with new-onset TB were identified and classified as treatment incompletion (n=706, 61.13%) or completion (n=449). Gender and age distribution was similar in both groups. Under multivariable logistic regression, advanced cancer (stage III and IV) and no first-line TB drugs use were independent factors for treatment incompletion; but older age was not significant. For patients surviving >1 year since TB diagnosis, independent factors for treatment incompletion included no first-line TB drugs use (except pyrazinamide) and absence of hypertension. Cancer stage had borderline significance.

CONCLUSIONS

TB treatment incompletion occurred in 61.13% of lung cancer patients. Clinicians should carefully titrate anti-TB medications and monitor side effects in lung cancer patients, especially those with treatment incompletion risk factors, to avoid treatment interruption due to fragility and/or drug intolerance.

Influence of CYP2C19 Polymorphisms on the Pharmacokinetics of Omeprazole in Elderly Subjects

Omeprazole blocks the gastric H⁺ /K⁺  adenosine triphosphatase, thus inhibiting gastric acid secretion, and is metabolized by cytochrome P450 (CYP) 2C19. Due to the physiological changes in the elderly, there are different pharmacokinetic consequences compared to young people. The aim of this study was to evaluate the pharmacokinetic profiles of omeprazole in 15 elderly participants according to the CYP2C19 genotype. The concentration-time profiles of omeprazole and its metabolites, 5-hydroxy (5-OH) omeprazole and omeprazole sulfone, were similar between the CYP2C19 extensive metabolizer (EM) and intermediate metabolizer groups. In contrast, when comparing the EM group and CYP2C19 poor metabolizer (PM) group, the EM/PM geometric mean ratio (95% confidence interval) of area under the plasma concentration-time curve from time of dosing to the last measurable concentration was 0.52 (0.27-1.01) and that of the IM group was 0.71 (0.32-1.59), indicating that the exposure of omeprazole in the PM group was increased. The exposure of 5-OH omeprazole was significantly decreased in the PM group when compared to the EM group, with an EM/PM geometric mean ratio (95% confidence interval) of 2.20 (1.50-3.22). In conclusion, the tendency of drug exposure according to the CYP2C19 genotype in the elderly and young adults was similar in that the exposure level was highest in the PM group. However, when compared to young adults, the difference between the genotype groups was smaller in the elderly.

Marie B, Milavetz G, Herr K. Cannabidiol (CBD) Use by Older Adults for Acute and Chronic Pain

Legalization of cannabidiol (CBD) products has ignited interest in clinical practice and research. One desired indication includes possible pain-relieving effects of CBD. The purposes of the current article are to (1) clarify terminology relevant to cannabinoids; (2) explain and understand the pharmacotherapeutics of CBD; (3) examine research of the current use of CBD by older adults for treating pain; (4) discuss safety considerations with using CBD products; and (5) provide best practice recommendations for clinicians as they advise their older adult patients. A review of the literature demonstrated mixed results on the efficacy of CBD in relieving pain in older adults. There is inconsistency in the labeling of over-the-counter CBD products that can result in safety issues and will require more federal quality control. Likewise, gaps in knowledge regarding safety and efficacy of CBD use in older adults are vast and require further research. [Journal of Gerontological Nursing, 47(7), 6-15.].

Effectiveness of first-line abiraterone versus enzalutamide among patients ≥80 years of age with metastatic castration-resistant prostate cancer: A retrospective propensity score-weighted comparative cohort study

BACKGROUND

Metastatic castration-resistant prostate cancer (mCRPC) disproportionately affects the elderly. There is limited data assessing the efficacy and tolerability of abiraterone acetate (AA) versus enzalutamide in this population.

OBJECTIVE

To compare the clinical efficacy and tolerability of AA versus enzalutamide in patients ≥ 80 years with mCRPC.

DESIGN, SETTING AND PARTICIPANTS

A retrospective propensity-weighted comparative cohort study of first-line AA versus enzalutamide among patients with mCRPC aged ≥80 years.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Inverse probability treatment weights based on propensity scores were generated to assess the treatment effect of AA versus enzalutamide on time to PSA progression (TTPP), time to progression (TTP) (first of PSA/radiographic/clinical progression) and overall survival using a weighted Cox proportional hazards model. PSA response rate (PSA RR) was compared between groups using Χ².

RESULTS AND LIMITATIONS

One hundred fifty-three patients received AA, and 125 received enzalutamide. Enzalutamide was associated with higher PSA RR (61.6% vs 43.8%, P < 0.004), and TTP (hazard ratio [HR] 0.66, 95% confidence interval [CI] 0.50-0.88, P = 0.01) but not TTPP (HR 0.73, 95% CI 0.53-1.01, P = 0.06). There were significantly more dose reductions with enzalutamide (22.9% vs 44.8%, P > 0.001) but there was no interaction between median proportion of full dose received and TTPP or TTP for either drug. Rates of treatment discontinuation (for reasons other than progression) were also significantly different between AA and enzalutamide (28.8% vs 40.8%, respectively, P = 0.04). The most common reason for dose reductions and discontinuation of enzalutamide was fatigue (30.4% and 5.6%, respectively).

CONCLUSIONS

Despite more dose reductions and a higher treatment discontinuation rate, enzalutamide was associated with a higher PSA RR and longer time to progression, than AA. Given that clinical outcomes were not adversely impacted by decreased treatment exposure, dose modification may be a useful treatment strategy to balance toxicity and tolerance.

Functional CYP3A variants affecting tacrolimus trough blood concentrations in Chinese renal transplant recipients

The aim of this study was to identify novel genetic variants affecting tacrolimus trough blood concentrations. We analyzed the association between 58 single nucleotide polymorphisms (SNPs) across the CYP3A gene cluster and the log-transformed tacrolimus concentration/dose ratio (log (C₀/D)) in 819 renal transplant recipients (Discovery cohort). Multivariate linear regression was used to test for associations between tacrolimus log (C₀/D) and clinical factors. Luciferase reporter gene assays were used to evaluate the functions of select SNPs. Associations of putative functional SNPs with log (C₀/D) were further tested in 631 renal transplant recipients (Replication cohort). Nine SNPs were significantly associated with tacrolimus log (C₀/D) after adjustment for CYP3A5*3 and clinical factors. Dual luciferase reporter assays indicated that the rs4646450 G allele and rs3823812 T allele were significantly associated with increased normalized luciferase activity ratios (p < 0.01). Moreover, CYP3A7*2 was associated with higher TAC log(C₀/D) in the group of CYP3A5 expressers. Age, serum creatinine and hematocrit were significantly associated with tacrolimus log (C₀/D). CYP3A7*2, rs4646450, and rs3823812 are proposed as functional SNPs affecting tacrolimus trough blood concentrations in Chinese renal transplant recipients. Clinical factors also significantly affect tacrolimus metabolism.

Can Habitual Exercise Help Reduce Serum Concentrations of Lipophilic Chemical Mixtures? Association between Physical Activity and Persistent Organic Pollutants

BACKGROUND

Low-dose persistent organic pollutants (POPs), especially organochlorine pesticides (OCPs), have emerged as a new risk factor of many chronic diseases. As serum concentrations of POPs in humans are mainly determined by both their release from adipose tissue to circulation and their elimination from circulation, management of these internal pathways may be important in controlling the serum concentrations of POPs. As habitual physical activity can increase the elimination of POPs from circulation, we evaluated whether chronic physical activity is related to low serum POP concentrations.

METHODS

A cross-sectional study of 1,850 healthy adults (age ≥20 years) without cardio-metabolic diseases who participated in the U.S. National Health and Nutrition Examination Survey 1999 to 2004 was conducted. Information on moderate or vigorous leisure-time physical activity was obtained based on questionnaires. Serum concentrations of OCPs and polychlorinated biphenyls were investigated as typical POPs.

RESULTS

Serum concentrations of OCPs among physically active subjects were significantly lower than those among physically inactive subjects (312.8 ng/g lipid vs. 538.0 ng/g lipid, P<0.001). This difference was maintained after adjustment for potential confounders. When analyses were restricted to physically active subjects, there were small decreases in the serum concentrations of OCPs with increasing duration of physical activity, showing a curvilinear relationship over the whole range of physical activity (Pquadratic <0.001). In analyses stratified by age, sex, body mass index, and smoking status, a strong inverse association was similarly observed among all subgroups.

CONCLUSION

Physical activity may assist in decreasing serum concentrations of lipophilic chemical mixtures such as OCPs.

Sex Differences in Antipsychotic and Benzodiazepine Prescribing Patterns: A Cohort Study of Newly Admitted Nursing Home Residents with Dementia in Ontario, Canada

BACKGROUND

In nursing homes, residents with dementia frequently receive potentially inappropriate medications that are associated with an increased risk of adverse events. Despite known sex differences in clinical presentation and sociodemographic characteristics among persons with dementia, few studies have examined sex differences in patterns and predictors of potentially inappropriate medication use.

OBJECTIVES

The objectives of this study were to examine sex differences in the patterns of antipsychotic and benzodiazepine use in the 180 days following admission to a nursing home, estimate clinical and sociodemographic predictors of antipsychotic and benzodiazepine use in male and female residents, and explore the effects of modification by sex on the predictors of using these drug therapies.

METHODS

We conducted a retrospective cohort study of 35,169 adults aged 66 years and older with dementia who were newly admitted to nursing homes in Ontario, Canada between 2011 and 2014. Health administrative databases were linked to detailed clinical assessment data collected using the Resident Assessment Instrument (RAI-MDS 2.0). Cox proportional hazards models were adjusted for clinical and sociodemographic covariates to estimate the rate of antipsychotic and benzodiazepine initiation and discontinuation in the 180 days following nursing home admission in the total sample and stratified by sex. Sex-covariate interaction terms were used to assess whether sex modified the association between covariates and the rate of drug therapy initiation or discontinuation following nursing home entry.

RESULTS

Across 638 nursing homes, our analytical sample included 22,847 females and 12,322 males. At admission, male residents were more likely to be prevalent antipsychotic users than female residents (33.8% vs 28.3%; p < 0.001), and female residents were more likely to be prevalent benzodiazepine users than male residents (17.2% vs 15.3%, p < 0.001). In adjusted models, female residents were less likely to initiate an antipsychotic after admission (hazard ratio [HR] 0.79, 95% confidence interval [CI] 0.73-0.86); however, no sex difference was observed in the rate of benzodiazepine initiation (HR 1.04, 95% CI 0.96-1.12). Female residents were less likely than males to discontinue antipsychotics (HR 0.89, 95% CI 0.81-0.98) and benzodiazepines (HR 0.82, 95% CI 0.75-0.89). Sex modified the association between some covariates and the rate of changes in drug use (e.g., widowed males exhibited an increased rate of antipsychotic discontinuation (p-interaction = 0.03) compared with married males), but these associations were not statistically significant among females. Sex did not modify the effect of frailty on the rates of initiation and discontinuation.

CONCLUSIONS

Males and females with dementia differed in their exposure to antipsychotics and benzodiazepines at nursing home admission and their patterns of use following admission. A greater understanding of factors driving sex differences in potentially inappropriate medication use may help tailor interventions to reduce exposure in this vulnerable population.

Recent Advances in the Management of Migraine in Older Patients

Although the prevalence of migraine tends to decrease in the fifth to sixth decades of life, there are still a significant number of patients > 65 years of age who experience migraine or have new-onset migraine. Because these older patients are often excluded from clinical trials, there are fewer evidence-based treatment guidelines for them. Migraine treatment in the older population requires careful consideration of changes in medication metabolism and increased medical comorbidities. Furthermore, older patients can present with an atypical migraine phenotype and have a higher rate of secondary headache, which may lead to a delay in diagnosis and subsequent treatment. Classic preventive treatments for migraine, including tricyclic antidepressants, antiepileptic drugs, and beta blockers, often have intolerable side effects. In addition, the presence of coronary artery disease, stroke, and peripheral arterial disease precludes the use of typical rescue medications such as triptans. As such, there has been a dire need for novel acute and preventive treatments for older adults. The purpose of this review is to provide an update on novel acute and preventive treatments for migraine in the older population. The advantages of these therapies include their efficacy, favorable side-effect profile, particularly in patients with atherosclerotic disease, as well as their tolerability.

DNA methylation and histone acetylation changes to cytochrome P450 2E1 regulation in normal aging and impact on rates of drug metabolism in the liver

Aging is associated with reduced liver function that may increase the risk for adverse drug reactions in older adults. We hypothesized that age-related changes to epigenetic regulation of genes involved in drug metabolism may contribute to this effect. We reviewed published epigenome-wide studies of human blood and identified the cytochrome P450 2E1 (CYP2E1) gene as a top locus exhibiting epigenetic changes with age. To investigate potential functional changes with age in the liver, the primary organ of drug metabolism, we obtained liver tissue from mice aged 4-32 months from the National Institute on Aging. We assayed global DNA methylation (5-methylcytosine, 5mC), hydroxymethylation (5-hydroxymethylcytosine, 5hmC), and locus-specific 5mC and histone acetylation changes around mouse Cyp2e1. The mouse livers exhibit significant global decreases in 5mC and 5hmC with age. Furthermore, 5mC significantly increased with age at two regulatory regions of Cyp2e1 in tandem with decreases in its gene and protein expressions. H3K9ac levels also changed with age at both regulatory regions of Cyp2e1 investigated, while H3K27ac did not. To test if these epigenetic changes are associated with varying rates of drug metabolism, we assayed clearance of the CYP2E1-specific probe drug chlorzoxazone in microsome extracts from the same livers. CYP2E1 intrinsic clearance is associated with DNA methylation and H3K9ac levels at the Cyp2e1 locus but not with chronological age. This suggests that age-related epigenetic changes may influence rates of hepatic drug metabolism. In the future, epigenetic biomarkers could prove useful to guide dosing regimens in older adults.

Intensive weight loss and cognition: The dynamics of persistent organic pollutants in adipose tissue can explain the unexpected results from the Action for Health in Diabetes (Look AHEAD) study

OBJECTIVE

The aim of this paper is to propose a new hypothesis for the role of lipophilic chemical mixtures stored in adipose tissue in the development of dementia. Specifically, we present how the dynamics of these chemicals can explain the unexpected findings from the Action for Health in Diabetes (Look AHEAD) study, which failed to show long-term benefits of intentional weight loss on cognition, despite substantial improvements in many known risk factors for dementia. Moreover, we discuss how the role of obesity in the risk of dementia can change depending on the dynamics of these chemicals in adipose tissue.

NEW HYPOTHESIS

Human adipose tissue is widely contaminated with various neurotoxic chemicals. Typical examples are persistent organic pollutants (POPs), strong lipophilic chemicals with long half-lives. Both unintentional and intentional weight loss increases the release of POPs from adipocytes into the circulation. As POPs in the blood can easily reach the brain, the intentional weight-loss group of the Look AHEAD study may have experienced an unappreciated and long-term disadvantage on their cognition. Additionally, POPs may be involved in the link between obesity and dementia, as dysfunctional hypertrophic adipocytes enhance the release of POPs from adipocytes to the circulation through uncontrolled lipolysis. In contrast, metabolically healthy obese people may have a low risk of dementia because the safe storage of POPs in adipose tissue would decrease the amount of POPs reaching the brain.

MAJOR CHALLENGES FOR THE HYPOTHESIS

In human studies, there are practical difficulties involved with measuring POPs in the blood, including high costs and complex assays. As the serum concentrations of POPs are continuously affected by weight loss and gain, prospective studies may require serial measurements of POPs. In in-vitro and in-vivo experimental studies, how to simulate the exposure dose, duration, and mixture patterns in humans would be critical.

LINKAGE TO OTHER MAJOR THEORIES

Even though POPs are direct neurotoxins at a high dosage, low-dose POPs are mitochondrial toxins. Therefore, chronic exposure to low-dose POPs is linked to known key interrelated mechanisms in the pathogenesis of dementia, such as mitochondrial dysfunction and neuroinflammation.

Methicillin-resistant staphylococcus aureus pneumonia in older people: a diagnostic and therapeutic challenge

Pneumonia is one of the leading causes of death in older people, with high mortality rates (> 80%). One of the bacterial pathogens causing pneumonia is Staphylococcus aureus. The unique adaptive ability of S. aureus to a broad range of antibiotics has led to the emergence of methicillin-resistant S. aureus (MRSA) strain. MRSA pneumonia remains a relatively uncommon infection in older people, but it is associated with a very high mortality rate. We report two cases of MRSA pneumonia that highlight the severe clinical presentation and virulence of MRSA infections in geriatric population. MRSA pneumonia can present with mostly an uncontrollable clinical evolution and an infaust prognosis. Therefore, clinicians should be aware of MRSA pneumonia in patients with comorbidities, recent hospitalization with antibiotic treatment, previous MRSA infections and also in patients residing in nursing homes/revalidation centers. Low prevalence of MRSA combined with a lack of highly distinctive clinical features makes accurate targeting of empirical treatment with antibiotics very difficult. Currently, monotherapy with linezolid or vancomycin remain the first choice, in adult patients with proven MRSA infection. Despite the higher age related mortality rates, there are no specific treatment guidelines for older patients.

Special Topics in the Care of Older People with HIV

PURPOSE OF REVIEW

Antiretroviral therapy has enabled many people with HIV to live long lives with their infection, but the literature suggests that long term survivors are developing comorbidities and aging-related syndromes at earlier ages than their non-infected counterparts. In addition, there is evidence or sex-based differences in comorbidity risk.

RECENT FINDINGS

How to best care for people aging with HIV is not known, but the tools of comprehensive geriatric assessment can identify people at risk for decline. Newer antiretroviral therapies offer promise of fewer side effects and drug interactions. We will also discuss special needs of women aging with HIV.

SUMMARY

People with HIV and their providers are often unprepared to confront issues of aging, and each clinical program must develop methods to assess older patient and manage age-related complications and syndromes.

Decision-Making Preferences and Deprescribing: Perspectives of Older Adults and Companions About Their Medicines

Objectives

Polypharmacy in the older population is increasing-and can be harmful. It can be safe to reduce or carefully cease medicines (deprescribing) but a collaborative approach between patient and doctor is required. This study explores decision-making about polypharmacy with older adults and their companions.

Method

Semi-structured interviews were conducted with 30 older people (aged 75+ years, taking multiple medicines) and 15 companions. Framework analysis was used to identify qualitative themes.

Results

Participants varied considerably in attitudes towards medicines, preferences for involvement in decision-making, and openness to deprescribing. Three types were identified. Type 1 held positive attitudes towards medicines, and preferred to leave decisions to their doctor. Type 2 voiced ambivalent attitudes towards medicines, preferred a proactive role, and were open to deprescribing. Type 3 were frail, perceived they lacked knowledge about medicines, and deferred most decisions to their doctor or companion.

Discussion

This study provides a novel typology to describe differences between older people who are happy to take multiple medicines, and those who are open to deprescribing. To enable shared decision-making, prescribers need to adapt their communication about polypharmacy based on their patients' attitudes to medicines and preferences for involvement in decisions.

Neurotoxic chemicals in adipose tissue: A role in puzzling findings on obesity and dementia

Midlife obesity is associated with increased risk of dementia, whereas late-life obesity is commonly associated with a lower risk of dementia. Although methodologic issues are often discussed in this apparent risk reversal, chronic exposure to low-dose organochlorine pesticides (OCPs), an emerging risk factor for dementia in general populations, may contribute to a direct explanation for these differences. OCPs are strong lipophilic chemicals with very long half-lives (several years), primarily stored in adipose tissue and very slowly released and metabolized over years. As serum concentrations of neurotoxic OCPs strongly correlate with brain OCPs (r = 0.95), any condition enhancing the release of OCPs from the adipose tissue into circulation would increase the risk of dementia. Increased release of OCPs from adipose tissue typically occurs in (1) dysfunctional adipocytes accompanied by uncontrolled lipolysis and (2) weight loss. Weight gain may help sequester circulating OCPs in adipose tissue. As obesity is the most common reason that adipocytes become dysfunctional, midlife obesity can increase dementia risk through the chronic release of OCPs into circulation. However, late-life obesity potentially decreases dementia risk because weight loss after midlife will increase the release of OCPs while weight gain may actually decrease the release. These countervailing forces may underlie paradoxical associations with dementia of obesity in midlife vs late life which is influenced by weight change after midlife. This hypothesis should be tested in future experimental and human studies on obesity and dementia.

Geriatric Pharmacology: An Update

An aging worldwide population demands that anesthesiologists consider geriatrics a unique subset of patients requiring customization of practice. This article reviews the current literature investigating physiologic changes of the elderly that affect pharmacokinetics and pharmacodynamics. Changes in drug absorption, distribution, metabolism, and excretion are discussed as well as the ultimate effects of medications. Implications for practice regarding specific anesthetic and analgesic drugs are addressed. Despite the immense body of research that contributes to understanding of geriatric pharmacology, elderly patients often are excluded from rigorous research trials, and further scientific investigation to inform best practices for this group of patients is needed.

Characterizing the pharmacokinetics and pharmacodynamics of immunosuppressant medicines and patient outcomes in elderly renal transplant patients

This review examines what is currently known about the pharmacokinetics and pharmacodynamics of commonly prescribed immunosuppressant medicines, tacrolimus, cyclosporine, mycophenolate and prednisolone, in elderly renal transplant recipients, and reported patient outcomes in this cohort. Renal transplantation is increasing rapidly in the elderly, however, currently, long-term patient outcomes are relatively poor compared to younger adults. Some studies have suggested that elderly recipients may have higher dose-adjusted exposure and/or lower clearance of the calcineurin inhibitors tacrolimus and cyclosporine; with one study reporting up to 50% reduction in tacrolimus exposure in the elderly. Elderly transplant recipients do not appear to have higher dosage-adjusted exposure to mycophenolic acid (MPA). The effects of ageing on the pharmacokinetics of prednisolone are unknown. Only one study has examined how aging effects drug target enzymes, reporting no difference in baseline inosine 5'-monophosphate dehydrogenase (IMPDH) activity and MPA-induced IMPDH activity in elderly compared to younger adult renal transplant recipients. In elderly transplant recipients, immunosenescence likely lowers the risk of acute rejection, but increases the risk of drug-related adverse effects. Currently, the three main causes of death in elderly renal transplant recipients are cardiovascular disease, infection and malignancy. One study has showed that renal transplant recipients aged over 65 years are seven times more likely to die with a functioning graft compared with young adults (aged 18-29 years). This suggests that an optimal balance between immunosuppressant medicine efficacy and toxicity is not achieved in elderly recipients, and further studies are needed to foster long-term graft and patient survival. Lower maintenance immunosuppressant targets in elderly recipients may decrease patient susceptibility to drug side effects, however, further studies are required and appropriate targets need to be established.

Older HIV-infected adults: complex patients- geriatric syndromes (II)

With the widespread adoption of highly active antiretroviral therapy (HAART), HIV infection starts to be considered one of the many chronic illnesses of advanced age. A growing proportion of the affected patients is presently older than 50. It has been suggested that HIV infection may today represent a model of accelerated and accentuated ageing. The need for a closer collaboration between geriatricians and HIV physicians is being growingly recognised to better address the priorities and needs of HIV patients. The final aim behind the generation of such synergies resides in the design of personalised plans of interventions. These plans should stem from the results of a comprehensive assessment of the individual spanning clinical, environmental, and psychosocial domains. Through the early identification of stressors and risk factors potentially disrupting the homeostatic balance of frail patients (including those living with HIV), it might be possible to protect the "biologically old" (but not necessarily "chronologically old") HIV-infected people from developing detrimental geriatric syndromes. In this article, specific features making the ageing HIV population of special interest for geriatric medicine, and the importance of a multidisciplinary model of care are described. The final objective is to stress how the only way for adequately tackling the multifaceted frailty condition of people with HIV is to implement novel models of care based on the comprehensive geriatric assessment.

Population Pharmacokinetics of Doravirine and Exposure-Response Analysis in Individuals with HIV-1

Doravirine is a novel nonnucleoside reverse transcriptase inhibitor for the treatment of human immunodeficiency virus 1 (HIV-1) infection. A population pharmacokinetic (PK) model was developed for doravirine using pooled data from densely sampled phase 1 trials and from sparsely sampled phase 2b and phase 3 trials evaluating doravirine administered orally as a single entity or as part of a fixed-dose combination of doravirine-lamivudine-tenofovir disoproxil fumarate. A one-compartment model with linear clearance from the central compartment adequately described the clinical PK of doravirine. While weight, age, and healthy versus HIV-1 status were identified as statistically significant covariates affecting doravirine PK, the magnitude of their effects was not clinically meaningful. Other intrinsic factors (gender, body mass index, race, ethnicity, and renal function) did not have statistically significant or clinically meaningful effects on doravirine PK. Individual exposure estimates for individuals in the phase 2b and 3 trials obtained from the final model were used for subsequent exposure-response analyses for virologic response (proportion of individuals achieving <50 copies/ml) and virologic failure. The exposure-response relationships between these efficacy endpoints and doravirine PK were generally flat over the range of exposures achieved for the 100 mg once-daily regimen in the phase 3 trials, with a minimal decrease in efficacy in individuals in the lowest 10th percentile of steady-state doravirine concentration at 24 h values. These findings support 100 mg once daily as the selected dose of doravirine, with no dose adjustment warranted for the studied intrinsic factors.

Chemical pharmacotherapy for hospital-acquired pneumonia in the elderly

INTRODUCTION

Hospital-acquired pneumonia (HAP) is a potentially serious infection that primarily affects older patients. The number of patients affected by multidrug-resistant (MDR) bacteria is increasing, including infection from strains of Staphylococcus aureus, Enterobacteriaceae, and Pseudomonas aeruginosa.

AREAS COVERED

This article focuses specifically on HAP, excluding patients afflicted by ventilator-associated pneumonia (VAP). The pathogenesis and clinical features of HAP in the elderly are discussed as well as specific drug pharmacokinetic and pharmacodynamic considerations in elderly patients. The current recommended guidelines for the management of HAP are also discussed. Finally, the authors provide evidence on the empirical therapy used for the treatment of HAP and widely consider specific-pathogen treatment of HAP in elderly patients.

EXPERT OPINION

In patients not at risk of MDR organism infection, antibiotics including piperacillin-tazobactam, cefepime, carbapenems or fluorquinolones are recommended. However, the emergence of MDR organisms as causal agents of HAP makes it necessary to accurately assess risk factors to these pathogens and revise our knowledge on specific antimicrobial susceptibility patterns from each institution. The authors believe that broader-spectrum empiric antibiotic therapies that target P. aeruginosa and methicillin-resistant S. aureus are best recommended in elderly patients at risk of HAP infection by MDR strains.

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.

Invasive Candidiasis in the Elderly: Considerations for Drug Therapy

Candida infections in the elderly are an important and expanding clinical problem, with significantly higher mortality in this group than in younger patients. The increasing problem of invasive Candida infections may be related to higher prevalence of immunocompromised older people and the emergence of treatment resistance. Older people, especially the frail and critically ill, are at higher risk of medication-related harmful effects due to changes in pharmacokinetics and pharmacodynamics, which may be further complicated by organ dysfunction, diminished homeostatic control, co-morbidities and polypharmacy. Here, we review the available options for the treatment of Candida infections and provide insights into the challenges surrounding the optimal use of antifungal drugs in the elderly.

Impact of UGT2B7 and ABCC2 genetic polymorphisms on mycophenolic acid metabolism in Chinese renal transplant recipients

AIM

To evaluate genetic variants affecting mycophenolic acid (MPA) metabolism in Chinese renal transplant recipients.

METHODS

Total 11 SNPs of UGT1A9, UGT1A8, UGT2B7, ABCC2, ABCG2 and SLCO1B3 were genotyped in 408 Chinese renal transplant recipients. Associations between SNPs and MPA concentration/dose ratio (C₀/D) were analyzed using different genetic models. Multivariate linear regression was used to analyze associations between log (C₀/D) and clinical factors. Results: After adjustment by clinical factors, UGT2B7 rs7662029 was associated with log (C₀/D) using a dominant (p = 0.041) and an additive (p = 0.038) model, ABCC2 rs717620 was associated with log (C₀/D) using a recessive model (p = 0.019). Using additive model, SNP-SNP interactions were identified (p = 0.002) between ABCC2 rs717620 and UGT1A9 rs2741049, with interactions (p = 0.002) between ABCC2 rs717620 and UGT1A8 rs1042597. Age, albumin and serum creatinine were associated with log (C₀/D).

CONCLUSION

rs7662029 and rs717620 may affect MPA pharmacokinetics. SNP-SNP interactions and clinical factors may have significant effects on MPA metabolism.

Challenges and innovations of drug delivery in older age

Both drug delivery performance and various age-related physical, mental and physiological changes can affect drug effectiveness and safety in elderly patients. The many drug delivery systems developed over the years include recent novel transdermal, nasal, pulmonary and orally disintegrating tablets that provide consistent, precise, timely and more targeted drug delivery. Certain drug delivery systems may be associated with suboptimal outcomes in the elderly because of the nature of drug present, a lack of appreciation of the impact of age-related changes in drug absorption, distribution and clearance, the limited availability of pharmacokinetic, safety and clinical data. Polypharmacy, patient morbidity and poor adherence can also contribute to sub-optimal drug delivery systems outcomes in the elderly. The development of drug delivery systems for the elderly is a poorly realised opportunity, with each system having specific advantages and limitations. A key challenge is to provide the innovation that best meets the specific physiological, psychological and multiple drug requirements of individual elderly patients.

Drug therapy, potential interactions and iatrogenesis as factors related to frailty in the elderly

Abstract Objective: to investigate the use of drugs, potential drug interactions and iatrogenesis, as factors associated with frailty. Method: an observational, cross-sectional, population-based study of elderly persons registered with the Family Health Strategies of the urban area of a municipal region in the south of Brazil was carried out. The sample was probabilistic and involved 554 elderly persons; and the proportional stratified sampling technique by FHS and gender was used. Data collection was performed in the home, with the gathering of information regarding sociodemographic characteristics and pharmacotherapeutic profile and the evaluation of frailty based on Fried et al. (2001). Results: medications were taken by 86.3% of the elderly and there was a prevalence of frailty of 63.0%. A total of 39.4% of the elderly were exposed to polypharmacy, 49.1% used potentially inappropriate medications and 52.2% were exposed to potential drug interactions, the most frequent being enalapril and metformin. An association between increased risk of frailty and the variables: polypharmacy; use of potentially inappropriate medications; potential drug interactions; more than two potential drug interactions with the presence or absence of potentially inappropriate medication was identified. Conclusion: an association was found between frailty and polypharmacy, the use of potentially inappropriate medication and the presence of drug interactions. The findings underscore the importance of the monitoring of drug therapy in this population group with a view to the early detection, prevention and resolution of iatrogenesis arising from the use of medicines.

Sugammadex Rescue in Avoiding Intensive Care Unit Admission in an Octogenarian Undergoing Emergency Laparotomy

Postlaparotomy management for elderly patients with underlying comorbidities is always a challenge because of poor cardiorespiratory reserves and prolonged effect of anesthetic drugs. For these reasons, such patients usually require intensive care unit (ICU) admission in the postoperative period. We report a case of an 85-year-old chronic smoker with controlled diabetes mellitus who needed an emergency laparotomy for a perforated gastric ulcer. Unfortunately, there was a shortage of ICU backup. With the successful conduct of an early surgery using combined general and regional anesthesia, the use of sugammadex (Bridion, Merck Sharp & Dohme Corp, Oss, the Netherlands) as a reversal agent, a skilled surgeon, and good postanesthesia care, the patient did not require ICU admission. He recovered fast and was discharged home 4 days after surgery. This case study aims to contribute to the literature on experience of a successful conduct of anesthesia in a high-risk geriatric patient when ICU facilities are limited.

Deprescribing Benzodiazepines in Older Patients: Impact of Interventions Targeting Physicians, Pharmacists, and Patients

Benzodiazepines (BZDs; including the related Z-drugs) are frequently targets for deprescribing; long-term use in older people is harmful and often not beneficial. BZDs can result in significant harms, including falls, fractures, cognitive impairment, car crashes and a significant financial and legal burden to society. Deprescribing BZDs is problematic due to a complex interaction of drug, patient, physician and systematic barriers, including concern about a potentially distressing but rarely fatal withdrawal syndrome. Multiple studies have trialled interventions to deprescribe BZDs in older people and are discussed in this narrative review. Reported success rates of deprescribing BZD interventions range between 27 and 80%, and this variability can be attributed to heterogeneity of methodological approaches and limited generalisability to cognitively impaired patients. Interventions targeting the patient and/or carer include raising awareness (direct-to-consumer education, minimal interventions, and 'one-off' geriatrician counselling) and resourcing the patient (gradual dose reduction [GDR] with or without cognitive behavioural therapy, teaching relaxation techniques, and sleep hygiene). These are effective if the patient is motivated to cease and is not significantly cognitively impaired. Interventions targeted to physicians include prescribing interventions by audit, algorithm or medication review, and providing supervised GDR in combination with medication substitution. Pharmacists have less frequently been the targets for studies, but have key roles in several multifaceted interventions. Interventions are evaluated according to the Behaviour Change Wheel. Research supports trialling a stepwise approach in the cognitively intact older person, but having a low threshold to use less-consultative methods in patients with dementia. Several resources are available to support deprescribing of BZDs in clinical practice, including online protocols.

Antiretroviral therapy in geriatric HIV patients: the GEPPO cohort study

Background

GEPPO is a prospective observational multi-centric cohort including HIV-infected geriatric patients. We hypothesized that the GEPPO cohort may help characterize antiretroviral (ARV) prescribing criteria used in real life by Italian infectious disease (ID) physicians.

Methods

This was a cross-sectional study describing the current ARV regimen in a geriatric HIV population (≥65 years). Antiretroviral strategies were categorized as follows: (i) multidrug regimens (MDRs), which comprised triple or mega ART combinations; (ii) less drug regimens (LDRs), which comprised fewer than three ART compounds. Multi-morbidity (MM) was defined as the presence of three or more non-communicable diseases, and polypharmacy (PP) as the use of five or more medications in chronic use. Four alternative combinations (MM+PP+, MM+PP-, MM-PP+, MM-PP-) were used in logistic regression analyses.

Results

A total of 1222 HIV-positive patients were included (median age 70 years). Females composed 16% of the cohort. Median duration of HIV infection was 17 years; 335 population members had been infected for >20 years. MM was present in 64% and PP in 37% of the patients. Treatment consisted of triple therapy in 66.4%, dual therapy in 25.3%, monotherapy in 6.5% and 'mega-ART' with more than three drugs in 1.64% of the patients. In multivariate logistic regression MM and PP were predictive for mono-dual, NRTI-sparing and tenofovir disoproxil fumarate (TDF)-sparing combinations. Female gender and age were predictors of unboosted ARV regimens.

Conclusions

High prevalence of non-conventional ARV regimens in elderly HIV patients suggests that clinicians try to tailor ARV regimens according to age, HIV duration, MM and PP.

DR, Lee DH. Persistent Organic Pollutants and Type 2 Diabetes: A Critical Review of Review Articles

Low dose persistent organic pollutants (POPs) have emerged as a new risk for type 2 diabetes (T2D). Despite substantial evidence from human and experimental studies, there are several critical issues which have not been properly addressed by POPs researchers. First, as POPs exist as mixtures, findings about POPs from human studies should be interpreted from the viewpoint of lipophilic chemical mixtures which include both measured and unmeasured POPs. Second, as POPs can directly reduce insulin secretion of beta cells, the role of POPs may be more prominent in the development of beta-cell dysfunction-dominant T2D rather than insulin resistance-dominant T2D. Third, there are multidimensional interrelationships between POPs and adipose tissue. Even though POPs are now considered as a new risk factor for T2D, independent of obesity, POPs and obesity are mechanistically linked to each other. POPs are involved in key mechanisms linking obesity and T2D, such as chronic inflammation of adipose tissue and lipotoxicity with ectopic fat accumulation. Also, POPs can explain puzzling human findings which suggest benefits of obesity because healthy adipose tissue can be protective by reducing the amount of POPs reaching other organs. Fourth, non-linear dose-response relationships between POPs and T2D are biologically possible. Although POPs are well-known endocrine disrupting chemicals (EDCs), mitochondrial dysfunction may be a more plausible mechanism due to unpredictability of EDC mixtures. As adipose tissue plays a role as an internal exposure source of POPs, how to manage POPs inside us may be essential to protect against harms of POPs.

Severe recurrent hypothermia in an elderly patient with refractory mania associated with atypical antipsychotic, valproic acid and oxcarbazepine therapy

Hypothermia is a rare but serious condition that has been associated with various psychiatric medications. We present a 76-year-old woman with refractory mania who developed multiple episodes of severe hypothermia associated with several psychiatric medications including olanzapine, quetiapine, valproic acid and oxcarbazepine. These episodes resolved following discontinuation of the agents. The patient had never experienced hypothermia before, despite having been on these or similar agents for many years. With traditional treatments for mania not feasible, other medications were used to treat her including lithium, clonazepam, gabapentin and the novel protein kinase c inhibitor tamoxifen. The regimen resulted in some success and importantly, without triggering hypothermia. This case alerts clinicians to the rare side effect of hypothermia in response to various psychiatric medications, the fact that patients can suddenly develop this intolerance and suggests possible medications that may be used safely without triggering hypothermia.

A role of low dose chemical mixtures in adipose tissue in carcinogenesis

The Halifax project recently hypothesized a composite carcinogenic potential of the mixture of low dose chemicals which are commonly encountered environmentally, yet which are not classified as human carcinogens. A long neglected but important fact is that adipose tissue is an important exposure source for chemical mixtures. In fact, findings from human studies based on several persistent organic pollutants in general populations with only background exposure should be interpreted from the viewpoint of chemical mixtures because serum concentrations of these chemicals can be seen as surrogates for chemical mixtures in adipose tissue. Furthermore, in conditions such as obesity with dysfunctional adipocytes or weight loss in which lipolysis is increased, the amount of the chemical mixture released from adipose tissue to circulation is increased. Thus, both obesity and weight loss can enhance the chance of chemical mixtures reaching critical organs, however paradoxical this idea may be when fat mass is the only factor considered. The complicated, interrelated dynamics of adipocytes and chemical mixtures can explain puzzling findings related to body weight among cancer patients, including the obesity paradox. The contamination of fat in human diet with chemical mixtures, occurring for reasons similar to contamination of human adipose tissue, may be a missing factor which affects the association between dietary fat intake and cancer. The presence of chemical mixtures in adipose tissue should be considered in future cancer research, including clinical trials on weight management among cancer survivors.