Age-related changes in liver size and hepatic blood flow. The influence on drug metabolism in the elderly

Development and Evaluation of Ontogeny Functions of the Major UDP-Glucuronosyltransferase Enzymes to Underwrite Physiologically Based Pharmacokinetic Modeling in Pediatric Populations

Uridine 5'-diphospho-glucuronosyltransferases (UGTs) demonstrate variable expression in the pediatric population. Thus, understanding of age-dependent maturation of UGTs is critical for accurate pediatric pharmacokinetics (PK) prediction of drugs that are susceptible for glucuronidation. Ontogeny functions of major UGTs have been previously developed and reported. However, those ontogeny functions are based on in vitro data (i.e., enzyme abundance, in vitro substrate activity, and so on) and therefore, may not translate to in vivo maturation of UGTs in the clinical setting. This report describes meta-analysis of the literature to develop and compare ontogeny functions for 8 primary UGTs (UGT1A1, UGT1A4, UGT1A6, UGT1A9, UGT2B7, UGT2B10, UGT2B15, and UGT2B17) based on published in vitro and in vivo studies. Once integrated with physiologically based pharmacokinetics modeling models, in vivo activity-based ontogeny functions demonstrated somewhat greater prediction accuracy (mean squared error, MSE: 0.05) compared to in vitro activity (MSE: 0.104) and in vitro abundance-based ontogeny functions (MSE: 0.129).

A Validated UHPLC-MS/MS Method for Determination of Nalbuphine in Human Plasma and Application for Pharmacokinetic Study of Patients Undergoing General Anesthesia

Nalbuphine was a semisynthetic opioid analgesic widely used in the treatment of both acute and chronic pain. We developed and validated a rapid, simple and sensitive method by ultra-performance liquid chromatography-tandem mass spectrometry (MS/MS) for the simultaneous quantitation of nalbuphine in human plasma, and we reported the pharmacokinetic features of patients during general anesthesia for abdominal surgery. Sample separation was achieved on a Kinetex Phenyl-Hexyl column (50 × 2.1 mm, 1.7 μm) after simple protein precipitation with acetonitrile. The mobile phase was composed of acetonitrile and 3 mM of ammonium acetate aqueous solution with 0.1% formic acid. Gradient elution was used in 4.5 min with a flow rate of 0.5 mL/min at 40°C. MS detection using AB Sciex QTRAP 5500 mass spectrometer was characterized by electrospray ionization for positive ions in multiple reaction monitoring mode. Quantitative ion pairs were m/z 358.4 → 340.1 for nalbuphine and m/z 340.0 → 268.3 for nalmefene, which were used as the internal standard (IS). The calibration curves showed good linearity (r2>0.99) over concentration range of 0.1-500 ng/mL. The intra-and inter-batch precisions were within 10.67%, and accuracy ranged from 94.07 to 105.34%. The IS-normalized matrix factors were 1.02-1.03 with RSD% (≤5.82%). The recoveries ranged from 101.09 to 106.30%. In conclusion, a rapid, simple, sensitive and economical analytical method was developed and validated to detect the concentration in plasma samples obtained from patients receiving nalbuphine intravenous injection and was successfully applicated to human pharmacokinetic studies of nalbuphine.

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).

Using deep learning to predict abdominal age from liver and pancreas magnetic resonance images

With age, the prevalence of diseases such as fatty liver disease, cirrhosis, and type two diabetes increases. Approaches to both predict abdominal age and identify risk factors for accelerated abdominal age may ultimately lead to advances that will delay the onset of these diseases. We build an abdominal age predictor by training convolutional neural networks to predict abdominal age (or "AbdAge") from 45,552 liver magnetic resonance images [MRIs] and 36,784 pancreas MRIs (R-Squared = 73.3 ± 0.6; mean absolute error = 2.94 ± 0.03 years). Attention maps show that the prediction is driven by both liver and pancreas anatomical features, and surrounding organs and tissue. Abdominal aging is a complex trait, partially heritable (h_g² = 26.3 ± 1.9%), and associated with 16 genetic loci (e.g. in PLEKHA1 and EFEMP1), biomarkers (e.g body impedance), clinical phenotypes (e.g, chest pain), diseases (e.g. hypertension), environmental (e.g smoking), and socioeconomic (e.g education, income) factors.

Toxicokinetics of U-47700, tramadol, and their main metabolites in pigs following intravenous administration: is a multiple species allometric scaling approach useful for the extrapolation of toxicokinetic parameters to humans?

New synthetic opioids (NSOs) pose a public health concern since their emergence on the illicit drug market and are gaining increasing importance in forensic toxicology. Like many other new psychoactive substances, NSOs are consumed without any preclinical safety data or any knowledge on toxicokinetic (TK) data. Due to ethical reasons, controlled human TK studies cannot be performed for the assessment of these relevant data. As an alternative animal experimental approach, six pigs per drug received a single intravenous dose of 100 µg/kg body weight (BW) of U-47700 or 1000 µg/kg BW of tramadol to evaluate whether this species is suitable to assess the TK of NSOs. The drugs were determined in serum and whole blood using a fully validated method based on solid-phase extraction and LC–MS/MS. The concentration–time profiles and a population (pop) TK analysis revealed that a three-compartment model best described the TK data of both opioids. Central volumes of distribution were 0.94 L/kg for U-47700 and 1.25 L/kg for tramadol and central (metabolic) clearances were estimated at 1.57 L/h/kg and 1.85 L/h/kg for U-47700 and tramadol, respectively. The final popTK model parameters for pigs were upscaled via allometric scaling techniques. In comparison to published human data, concentration–time profiles for tramadol could successfully be predicted with single species allometric scaling. Furthermore, possible profiles for U-47700 in humans were simulated. The findings of this study indicate that unlike a multiple species scaling approach, pigs in conjunction with TK modeling are a suitable tool for the assessment of TK data of NSOs and the prediction of human TK data.

Tacrolimus Dose-Conversion Ratios Based on Switching of Formulations for Patients with Solid Organ Transplants

Background

Tacrolimus may be administered during hospitalization as an IV formulation or oral suspension. However, literature suggesting appropriate ratios for conversion from these formulations to capsules is limited.

Objective

To evaluate conversion ratios after a switch in formulation of tacrolimus for solid-organ transplant recipients.

Methods

This single-centre observational longitudinal study involved hospitalized patients who underwent a switch in formulation of tacrolimus according to 1 of 3 possible scenarios: IV to oral suspension, IV to capsule, or oral suspension to capsule. Data were collected from the earliest accessible electronic file (January 2009) to January 1, 2019. Conversion ratios were calculated for each of the 3 groups using data for blood concentrations and doses before and after the switch. The calculated ratios were then compared with recommended conversion ratios: 1:5 (i.e., 1 mg of IV tacrolimus is converted to 5 mg of oral tacrolimus, expressed as "5") for either of the switches involving an IV formulation and 1:1 (i.e., same amount, expressed as "1") for the switch from oral formulation to capsules.

Results

For the group who underwent switching from the IV formulation to oral suspension, the mean calculated conversion ratio was 3.04, which was significantly different from the recommended ratio of 5. For the group who underwent switching from the IV formulation to capsules, the calculated conversion ratio was 5.18, which was not significantly different from the recommended ratio of 5. For the group who underwent switching from oral suspension to capsules, the calculated conversion ratio was 1.17, which was not significantly different from the recommended ratio of 1.

Conclusion

In this small retrospective study of tacrolimus therapy, the calculated conversion ratio was significantly different from the recommended ratio for patients who were switched from IV administration to oral suspension, but not for those switched from IV administration or oral suspension to capsules. Therapeutic drug monitoring therefore appears indispensable, regardless of conversion ratios.

Development of a physiologically based pharmacokinetic (PBPK) population model for Chinese elderly subjects

Aims

This study aims to develop and verify a physiologically based pharmacokinetic (PBPK) population model for the Chinese geriatric population in Simcyp.

Methods

Firstly, physiological information for the Chinese geriatric population was collected and later employed to develop the Chinese geriatric population model by recalibration of corresponding physiological parameters in the Chinese adult population model available in Simcyp (i.e., Chinese healthy volunteer model). Secondly, drug‐dependent parameters were collected for six drugs with different elimination pathways (i.e., metabolized by CYP1A2, CYP3A4 or renal excretion). The drug models were then developed and verified by clinical data from Chinese adults, Caucasian adults and Caucasian elderly subjects to ensure that drug‐dependent parameters are correctly inputted. Finally, the tested drug models in combination with the newly developed Chinese geriatric population model were applied to simulate drug concentration in Chinese elderly subjects. The predicted results were then compared with the observations to evaluate model prediction performance.

Results

Ninety‐eight per cent of predicted AUC, 95% of predicted C_max, and 100% of predicted CL values were within two‐fold of the observed values, indicating all drug models were properly developed. The drug models, combined with the newly developed population model, were then used to predict pharmacokinetics in Chinese elderly subjects aged 60–93. The predicted AUC, C_max, and CL values were all within two‐fold of the observed values.

Conclusion

The population model for the Chinese elderly subjects appears to adequately predict the concentration of the drug that was metabolized by CYP1A2, CYP3A4 or eliminated by renal clearance.

Population Pharmacokinetics of Esketamine Nasal Spray and its Metabolite Noresketamine in Healthy Subjects and Patients with Treatment-Resistant Depression

BACKGROUND

Esketamine nasal spray is approved for treatment-resistant depression.

OBJECTIVE

The objective of this study was to characterize the pharmacokinetics of esketamine and noresketamine in healthy subjects and patients with treatment-resistant depression.

METHODS

Esketamine and noresketamine were measured in > 9000 plasma samples collected from 820 individuals who received esketamine by the intranasal, intravenous, and oral routes. An open linear model for esketamine (three compartments) and noresketamine (two compartments) that included a hepato-portal compartment was developed using NONMEM^® VII. The effects of covariates on esketamine pharmacokinetics and a model evaluation were performed using conventional methods.

RESULTS

The fraction of a 28-mg intranasal dose absorbed through the nasal cavity (FR_n) is 54% (100% of this fraction is completely absorbed); the remaining 46% is swallowed and undergoes intestinal and first-pass metabolism and 18.6% of the swallowed dose reaches the systemic circulation. The absolute bioavailability of 56 and 84 mg of intranasal esketamine is 54 and 51%, respectively. Esketamine volume at steady state and clearance were 752 L and 114 L/h, respectively. Noresketamine volume at steady state and apparent clearance were 185 L and 38 L/h, respectively. Relative to non-Asian subjects, Asian subjects showed a 64.0 and 19.4% decrease in the esketamine elimination rate constant and noresketamine apparent clearance, respectively. Japanese subjects exhibited a 34% increase in FR_n vs other races. Hepatic blood flow decreased by 21.9 L/h for each decade in age in subjects aged > 60 years. These changes resulted in esketamine and noresketamine maximum concentration and area under the concentration-time curve after 24 h post-dose values that were up to 36% higher than those observed in other races or in younger adult subjects.

CONCLUSIONS

Esketamine and noresketamine pharmacokinetics was successfully characterized in healthy subjects and patients with treatment-resistant depression. The model quantified esketamine absolute nasal and oral bioavailability, its hepatic flow-limited clearance and biotransformation to the major metabolite noresketamine, and the influence of intrinsic and extrinsic factors on esketamine pharmacokinetics. Clinical trials registration numbers of the studies included in the analysis: ESKETINTRD1001 (NCT01780259), ESKETINTRD1002 (NCT01980303), ESKETINTRD1003 (NCT02129088), ESKETINTRD1008 (NCT02846519), ESKETINTRD1009 (NCT02343289), ESKETINTRD1010 (NCT02568176), ESKETINTRD1012 (NCT02345148), 54135419TRD1015 (NCT02682225), ESKETINTRD2003 (NCT01998958), ESKETINSUI2001 (NCT02133001), ESKETINTRD3001 (NCT02417064), ESKETINTRD3002 (NCT02418585), and ESKETINTRD3005 (NCT02422186).

Avoidability of drug-induced liver injury (DILI) in an elderly hospital cohort with cases assessed for causality by the updated RUCAM score

Background

Drug-induced liver injury (DILI) represents an increasing morbidity in the general population, but more so in the elderly cohort of patients. Despite this, the concept of its prevention through prospective analysis has largely remained unexamined. We evaluated the utility of recently validated adverse drug reactions (ADR) avoidability tool in a cohort of elderly patients with DILI.

Methods

We examined 38 DILI-drug pairs from n=38 patients in a prospective cohort of patients presenting with adverse drug reactions to a Weill Cornell-affiliated tertiary hospital between February 2019 and January 2020. DILI outcomes were adjudicated by the updated Roussel Uclaf Causality Assessment Method (RUCAM). Two clinical pharmacologists and two general physicians utilized the Liverpool adverse drug reactions avoidability tool (LAAT) and the modified Hallas tools to rate the preventability of DILI-drug pairs. Inter-rater, exact agreement proportions, as well as intraclass correlation coefficients were generated and expressed as ordinal outcomes.

Results

The cases examined for the determination of DILI avoidability had probability likelihood of “probable” or “highly probable” by the updated RUCAM scale. Examination of the 38 DILI-drug pairs (n= 38 patients) resulted in a total of 152 ordinal outcome decisions. We found about 32.3% (50/152) and 34.2% (52/152) of DILI-drug pairs were rated as “avoidable” (“probable” or “definite”) by the LAAT and the modified Hallas tools respectively. The overall median Krippendorf’s kappa with the LAAT was 0.61 (SE 0.12, CI 0.36, 0.85) and for modified Hallas tool was 0.53 (SE 0.18; CI 0.16, 0.89). The inter-rater correlation coefficient (ICC) for the LAAT and modified Hallas were 0.50 [0.32, 0.65] and 0.63 [0.48, 0.76] respectively. Exact pairwise agreement was present in 30/38 (IQR 29.5, 34.5), and 28/38 (IQR 27.5-35.5) of DILI-ADR pairs using the LAAT and modified Hallas tools respectively.

Conclusion

We found a significant proportion of drug-induced liver injury adjudicated by the updated RUCAM scale in elderly hospitalized cohort of patients were avoidable with significant implication for therapeutic commissioning as well as cost effectiveness interventions in this cohort of patients.

Updates on the Pharmacology of Chloroquine against Coronavirus Disease 2019 (COVID-19): A Perspective on its Use in the General and Geriatric Population

BACKGROUND

Chloroquine has been used to treat malaria for more than 70 years. Its safety profile and cost-effectiveness are well-documented. Scientists have found that chloroquine has in vitro activity against novel coronavirus (SARS-CoV-2). Currently, chloroquine has been adopted in the Protocol for Managing Coronavirus Disease 2019 (COVID-19) (Version 7) issued by the China National Health Commission for clinically managing COVID-19.

OBJECTIVE

This review will focus on the antiviral mechanism, effectiveness and safety, dosage and DDIs of chloroquine, for the purpose of providing evidence-based support for rational use of chloroquine in the treatment of COVID-19.

METHODS

Use the search terms "chloroquine" linked with "effectiveness", "safety", "mechanism", "drug-drug interaction (DDIs)" or other terms respectively to search relevant literature through PubMed.

RESULTS

After searching, we found literature about antivirus mechanism, dosage, DDIs of chloroquine. However, studies on the effectiveness and safety of chloroquine treatment for COVID-19 for the general and geriatric patients are not enough.

CONCLUSION

According to literature reports, chloroquine has been proven to have anti-SARS-CoV-2 effect in vitro and the potential mechanism of chloroquine in vivo. Pharmacokinetic characteristics and DDIs study are helpful in guiding rational drug use in general and geriatric patients. Although there have been reports of successful clinical application of chloroquine in the treatment COVID-19, more clinical test data are still needed to prove its effectiveness and safety.

Effect of Environmental Exposure and Pharmacogenomics on Drug Metabolism

BACKGROUND

Pesticides are major xenobiotic compounds and environmental pollutants, which are able to alter drug-metabolizing enzyme as well as pharmacokinetics of drugs. Subsequent to the release of the human genome project, genetic variations (polymorphism) become an integral part of drug development due to their influence on disease susceptibility/ progression of the disease and their impact on drug absorption, distribution, metabolism of active metabolites and finally excretion of the drug. Genetic polymorphisms crucially regulate pharmacokinetics and pharmacodynamics of drugs under the influence of physiological condition, lifestyle, as well as pathological conditions collectively.

OBJECTIVE

To review all the evidence concerning the effect of environmental exposure on drug metabolism with reference to pharmacogenomics.

METHODS

Scientific data search and review of basic, epidemiological, pharmacogenomics and pharmacokinetics studies were undertaken to evaluate the influence of environmental contaminants on drug metabolism.

RESULTS

Various environmental contaminants like pesticides effectively alter drug metabolism at various levels under the influence of pharmacogenomics, which interferes with pharmacokinetics of drug metabolism. Genetic polymorphism of phase I and phase II xenobiotic-metabolizing enzymes remarkably alters disease susceptibility as well as the progression of disease under the influence of various environmental contaminants at various levels.

CONCLUSION

Individual specific drug response may be attributed to a large variety of factors alone or in combination ranging from genetic variations (SNP, insertion, deletion, duplication etc.) to physiological setting (gender, age, body size, and ethnicity), environmental or lifestyle factors (radiation exposure, smoking, alcohol, nutrition, exposure to toxins, etc.); and pathological conditions (obesity, diabetes, liver and renal function).

Rectus sheath single-injection blocks: a study to quantify local anaesthetic absorption using serial ultrasound measurements and lidocaine serum concentrations

Objectives

Rectus sheath blocks are an established option for analgesia following abdominal surgery, but pharmacokinetic data are limited. This study sought to characterise the absorption of lidocaine injectate and the pharmacokinetics of lidocaine after rectus sheath injection.

Methods

Bilateral rectus sheath single-injection blocks were given to 10 patients undergoing general or urological surgery. Afterwards, serial lidocaine serum levels and ultrasound measurements of the rectus sheath injectate reservoir were collected.

Key findings

Injectate within the rectus sheath was visible with ultrasound up to 12 h after injection. However, the rate of drug absorption exceeded that of injectate disappearance. Peak serum concentration occurred within 30 min with average peak concentrations of 1.65 μg/ml. Lidocaine clearance was lower than reported in young healthy subjects. The body mass index positively correlated with lidocaine terminal phase half-life, and clearance negatively correlated with age.

Conclusions

The study provides the first data describing lidocaine pharmacokinetics after rectus sheath injection. Peak serum concentrations transiently achieved systemic levels associated with pain relief after a single bolus injection. The data from this study could be used to develop a regime using single shot rectus sheath blockade with a bolus of lidocaine followed by infusion using bilateral rectus sheath catheters.

Ischemia-Reperfusion Injury in Aged Livers-The Energy Metabolism, Inflammatory Response, and Autophagy

Because of the lack of adequate organs, the number of patients with end-stage liver diseases, acute liver failure or hepatic malignancies waiting for liver transplantation is constantly increasing. Accepting aged liver grafts is one of the strategies expanding the donor pool to ease the discrepancy between the growing demand and the limited supply of donor organs. However, recipients of organs from old donors may show an increased posttransplantation morbidity and mortality due to enhanced ischemia-reperfusion injury. Energy metabolism, inflammatory response, and autophagy are 3 critical processes which are involved in the aging progress as well as in hepatic ischemia-reperfusion injury. Compared with young liver grafts, impairment of energy metabolism in aged liver grafts leads to lower adenosine triphosphate production and an enhanced generation of free radicals, both aggravating the inflammatory response. The aggravated inflammatory response determines the extent of hepatic ischemia-reperfusion injury and augments the liver damage. Autophagy protects cells by removal of damaged organelles, including dysfunctional mitochondria, a process impaired in aging and involved in ischemia-reperfusion-related apoptotic cell death. Furthermore, autophagic degradation of cellular compounds relieves intracellular adenosine triphosphate level for the energy depressed cells. Strategies targeting the mechanisms involved in energy metabolism, inflammatory response, and autophagy might be especially useful to prevent the increased risk for ischemia-reperfusion injury in aged livers after major hepatic surgery.

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.

Novel targets for delaying aging: The importance of the liver and advances in drug delivery

Age-related changes in liver function have a significant impact on systemic aging and susceptibility to age-related diseases. Nutrient sensing pathways have emerged as important targets for the development of drugs that delay aging and the onset age-related diseases. This supports a central role for the hepatic regulation of metabolism in the association between nutrition and aging. Recently, a role for liver sinusoidal endothelial cells (LSECs) in the relationship between aging and metabolism has also been proposed. Age-related loss of fenestrations within LSECs impairs the transfer of substrates (such as lipoproteins and insulin) between sinusoidal blood and hepatocytes, resulting in post-prandial hyperlipidemia and insulin resistance. Targeted drug delivery methods such as nanoparticles and quantum dots will facilitate the direct delivery of drugs that regulate fenestrations in LSECs, providing an innovative approach to ameliorating age-related diseases and increasing healthspan.

Survivability of hospitalized chronic kidney disease (CKD) patients with moderate to severe estimated glomerular filtration rate (eGFR) after experiencing adverse drug reactions (ADRs) in a public healthcare center: a retrospective 3 year study

Background

Accurate identification and routine preventive practices are crucial steps in lessening the incidence of medications and patients related adverse drug reactions (ADRs).

Methods

Three years retrospective study was conducted among chronic kidney disease (CKD) patients at multi-wards in a tertiary healthcare center. Data collected included demographic characteristics, physical examination results, comorbid conditions, laboratory tests and medications taken. Only medication prescribed during the hospital stay were considered in this study.

Results

From this study only one ADR incident was definitely preventable and majority of other ADRs (88.3%) were possibly preventable. Type of renal replacement therapy (p = 0.023) and stages of renal function (p = 0.002) were significantly associated with survivability of the hospitalized CKD patients after ADRs. Highest percentage of mortality based on categories were 50–59 years (20.0%), male (16.3%), Indian ethnicity (23.7%), obese (15.0%), smoking (17.1%), consumes alcohol (17.4%), conservative management of renal disease (19.5%) and renal function of < 15 mL/min/1.73m². Overall survivability using Kaplan-Meier analysis reported a significant difference of 18-day survival rate between patients undergoing hemodialysis and patients conservatively managing their renal disease. The 18 days survival rate of patients undergoing hemodialysis, peritoneal dialysis and conservative management were 94.9%, 91.7% and 75.1% respectively. Eighteen days survival rate of patients with renal functions of 30–59 mL/min/1.73m², 15–29 mL/min/1.73m² and < 15 mL/min/1.73m² were 87.4%, 69.8% and 88.6% respectively. Similarly, Cox regression analysis revealed that renal replacement therapy was the only factor significantly contributed to ADRs related mortality. CKD patients whom conservatively managed renal disease or/and with renal function of < 15 mL/min/1.73m² had 5.61 and 5.33 higher mortality risk respectively.

Conclusion

Majority of the reported ADRs were possibly preventable. Renal replacement therapy and/or renal function were significant risk factors for mortality due to ADRs among hospitalized CKD patients stages 3 to 5. Clinician engagement, intensive resources and regular updates aided with online monitoring technology are needed for enhancing care and prevention of ADRs among CKD patients.

Drug Metabolism in the Liver

Metabolism is a biotransformation process, where endogenous and exogenous compounds are converted to more polar products to facilitate their elimination from the body. The process of metabolism is divided into 3 phases. Phase I metabolism involves functionalization reactions. Phase II drug metabolism is a conjugation reaction. Phase III refers to transporter-mediated elimination of drug and/or metabolites from body normally via liver, gut, kidney, or lung. This review presents basic information on drug-metabolizing enzymes and potential factors that might affect the metabolic capacities of the enzyme or alter drug response or drug-mediated toxicities.

In vitro metabolism of specific CYP2D and CYP3A opioid substrates using rat liver S9 fractions and mass spectrometry reveal a severe metabolic impairment with increasing age

Codeine and oxycodone are opioids used to alleviate pain. The outcome of the treatment is ultimately related to their metabolism by Cytochromes P450 (CYPs). Depending on the drugs used, alterations in the metabolism of drugs by CYPs can lead to severe consequences including alterations in their efficacy, safety and toxicity. The objectives of this study were to develop a novel HPLC-MS/MS method capable of quantifying codeine and oxycodone along with specific metabolites using an isotopic dilution strategy and study the rate of formation of morphine (CYP2D), norcodeine (CYP3A), oxymorphone (CYP2D) and noroxycodone (CYP3A). The chromatographic separation was achieved using a Biobasic C₁₈ 100 × 1 mm column combined with an isocratic mobile phase composed of methanol and 10 mm ammonium acetate (40:60) at a flow rate of 75 μL/min. The mass spectrometer was operating in scan mode MS/MS and the analytical range was set at 10-10 000 nm. The precision (RSD) and accuracy (RE) observed were 4.4-11.5 and -9.1-6.1% respectively. Liver S9 fractions from 3-, 6-, 12- and 18-month-old male Sprague-Dawley rats were prepared and Michaelis-Menten parameters were determined. The derived maximum enzyme velocity suggested a rapid saturation of the CYP2D and CYP3A active sites in the liver S9 fractions of 18-month-old rats. Moreover, metabolic stabilities of codeine and oxycodone in rat liver S9 fractions were significantly greater for the 18-month-old rats. This study suggests that there is an impairment of CYP2D and CYP3A metabolism in aging rats.

Methods to reduce prescribing errors in elderly patients with multimorbidity

The global population of multimorbid older people is growing steadily. Multimorbidity is the principal cause of complex polypharmacy, which in turn is the prime risk factor for inappropriate prescribing and adverse drug reactions and events. Those who prescribe for older frailer multimorbid people are particularly prone to committing prescribing errors of various kinds. The causes of prescribing errors in this patient population are multifaceted and complex, including prescribers' lack of knowledge of aging physiology, geriatric medicine, and geriatric pharmacotherapy, overprescribing that frequently leads to major polypharmacy, inappropriate prescribing, and inappropriate drug omission. This review examines the various ways of minimizing prescribing errors in multimorbid older people. The role of education in physician prescribers and clinical pharmacists, the use of implicit and explicit prescribing criteria designed to improve medication appropriateness in older people, and the application of information and communication-technology systems to minimize errors are discussed in detail. Although evidence to support any single intervention to prevent prescribing errors in multimorbid elderly people is inconclusive or lacking, published data support focused prescriber education in geriatric pharmacotherapy, routine application of STOPP/START (screening tool of older people's prescriptions/screening tool to alert to right treatment) criteria for potentially inappropriate prescribing, electronic prescribing, and close liaison between clinical pharmacists and physicians in relation to structured medication review and reconciliation. Carrying out a structured medication review aimed at optimizing pharmacotherapy in this vulnerable patient population presents a major challenge. Another challenge is to design, build, validate, and test by clinical trials suitably versatile and efficient software engines that can reliably and swiftly perform complex medication reviews in older multimorbid people. The European Union-funded SENATOR and OPERAM clinical trials commencing in 2016 will examine the impact of customized software engines in reducing medication-related morbidity, avoidable excess cost, and rehospitalization in older multimorbid people.

Predicting risk of adverse drug reactions in older adults

Adverse drug reactions (ADRs) are common in older adults, with falls, orthostatic hypotension, delirium, renal failure, gastrointestinal and intracranial bleeding being amongst the most common clinical manifestations. ADR risk increases with age-related changes in pharmacokinetics and pharmacodynamics, increasing burden of comorbidity, polypharmacy, inappropriate prescribing and suboptimal monitoring of drugs. ADRs are a preventable cause of harm to patients and an unnecessary waste of healthcare resources. Several ADR risk tools exist but none has sufficient predictive value for clinical practice. Good clinical practice for detecting and predicting ADRs in vulnerable patients includes detailed documentation and regular review of prescribed and over-the-counter medications through standardized medication reconciliation. New medications should be prescribed cautiously with clear therapeutic goals and recognition of the impact a drug can have on multiple organ systems. Prescribers should regularly review medication efficacy and be vigilant for ADRs and their contributory risk factors. Deprescribing should occur at an individual level when drugs are no longer efficacious or beneficial or when safer alternatives exist. Inappropriate prescribing and unnecessary polypharmacy should be minimized. Comprehensive geriatric assessment and the use of explicit prescribing criteria can be useful in this regard.

Management of psychiatric and neurological comorbidities in epilepsy

The treatment of epileptic seizure disorders is not restricted to the achievement of seizure-freedom, but must also include the management of comorbid medical, neurological, psychiatric and cognitive comorbidities. Psychiatric and neurological comorbidities are relatively common and often co-exist in people with epilepsy (PWE). For example, depression and anxiety disorders are the most common psychiatric comorbidities in PWE, and they are particularly common in PWE who also have a neurological comorbidity, such as migraine, stroke, traumatic brain injury or dementia. Moreover, psychiatric and neurological comorbodities often have a more severe impact on the quality of life in patients with treatment-resistant focal epilepsy than do the actual seizures. Epilepsy and psychiatric and neurological comorbidities have a complex relationship, which has a direct bearing on the management of both seizures and the comorbidities: the comorbidities have to be factored into the selection of antiepileptic drugs, and the susceptibility to seizures has to be considered when choosing the drugs to treat comorbidities. The aim of this Review is to highlight the complex relationship between epilepsy and common psychiatric and neurological comorbidities, and provide an overview of how treatment strategies for epilepsy can positively and negatively affect these comorbidities and vice versa.

Pharmacokinetics of antidepressants in patients with hepatic impairment

Appropriate use of antidepressant in patients with hepatic impairment requires careful consideration of how the hepatic illness may affect pharmacokinetics. This review aims to analyze pharmacokinetic profile, plasma level variations so as the metabolism of several antidepressants relating to their use in patients with an hepatic impairment. Due to the lack of data regarding hepatic impairment itself, the review is focused mainly on studies investigating pharmacokinetics in hepatic cirrhosis or alcohol-related conditions. More data on reduced hepatic metabolism can be extrapolated by drug studies conducted in elderly populations. Dose adjustment of antidepressants in these patients is important as most of these drugs are predominantly metabolized by the liver and many of them are associated with dose-dependent adverse reactions. As no surrogate parameter is available to predict hepatic metabolism of drugs, dose adjustment according to pharmacokinetic properties of the drugs is proposed. There is a need for a more balanced assessment of the benefits and risks associated with antidepressants use in patients with hepatic impairment, particularly considering pharmacokinetic profile of the drugs to ensure that patients, who would truly benefit from these agents, are not denied appropriate treatment. In conclusion, kinetic studies for centrally acting drugs including antidepressants with predominant hepatic metabolism should be carried out in patients with liver disease to allow precise dose recommendations for enhanced patient safety.

Appropriate prescribing in the elderly: Current perspectives

Advances in medical therapeutics have undoubtedly contributed to health gains and increases in life expectancy over the last century. However, there is growing evidence to suggest that therapeutic decisions in older patients are frequently suboptimal or potentially inappropriate and often result in negative outcomes such as adverse drug events, hospitalisation and increased healthcare resource utilisation. Several factors influence the appropriateness of medication selection in older patients including age-related changes in pharmacokinetics and pharmacodynamics, high numbers of concurrent medications, functional status and burden of co-morbid illness. With ever-increasing therapeutic options, escalating proportions of older patients worldwide, and varying degrees of prescriber education in geriatric pharmacotherapy, strategies to assist physicians in choosing appropriate pharmacotherapy for older patients may be helpful. In this paper, we describe important age-related pharmacological changes as well as the principal domains of prescribing appropriateness in older people. We highlight common examples of drug-drug and drug-disease interactions in older people. We present a clinical case in which the appropriateness of prescription medications is reviewed and corrective strategies suggested. We also discuss various approaches to optimising prescribing appropriateness in this population including the use of explicit and implicit prescribing appropriateness criteria, comprehensive geriatric assessment, clinical pharmacist review, prescriber education and computerized decision support tools.

Outcomes of living donor liver transplantation using elderly donors

Purpose

Living donor liver transplantation (LDLT) using elderly donors is increasing in frequency in response to organ shortage. However, elderly donor graft has been reported to negatively affect graft patency and patient survival.

Methods

We retrospectively reviewed the medical records of 604 patients who underwent LDLT at Seoul St. Mary's Hospital, The Catholic University of Korea between May 1999 and September 2012. Elderly donors were defined as those ≥55 years of age. Here, we evaluate the survival differences and causes of death of recipients of elderly donor grafts.

Results

The overall mortality rate of the recipients was significantly higher in the elderly donor group (group A) than in the younger donor group (group B: 46.2% vs. 18.1%, P = 0.004). The survival length of group A was significantly shorter than that of group B (31.2 ± 31.3 and 51.4 ± 40.8 months, P = 0.014). The significantly common causes of death in group A were biliary (41.7%) and arterial complication (16.7%), and it was higher than those in group B (P = 0.000 and P = 0.043, respectively).

Conclusion

LDLT using elderly donors could induce more serious complications and higher mortality rates than those at using younger donors. As such, careful donor selection is needed, especially with regard to assessing the condition of potential elderly donor livers. Furthermore, a large-volume and multicenter study of complications and outcomes of LDLT using elderly donor liver is required.

Complex association between alanine aminotransferase activity and mortality in general population: a systematic review and meta-analysis of prospective studies

Objective

Controversy exists in using alanine aminotransferase (ALT) activity for predicting long-term survival. Therefore, this research study investigated the association between ALT activity and mortality through a systematic review and meta-analysis of previous prospective studies.

Methods

Electronic literature databases, including PubMed, Embase, and the Institute for Scientific Information (ISI), were searched for relevant prospective observational studies (published before Dec 30, 2013) on the association between baseline ALT activity and ensuing all-cause/disease-specific mortality. Information on nationality, sample size, participant characteristics, follow-up duration, comparison, outcome assessment, hazard ratios (HRs) and adjusted covariates was extracted. Pooled HRs and corresponding 95% confidence intervals (CIs) were separately calculated for categorical risk estimates (highest vs. lowest ALT categories) and continuous risk estimates (per 5 U/l of ALT increment) in subgroups separated by age (<70/≥70 years).

Results

A total of twelve prospective cohort studies, totaling 206,678 participants and 16,249 deaths, were identified and analyzed. In the younger age group, the pooled HR for mortality related to liver-disease was about 1.24 (95% CI: 1.23–1.25) per 5 U/l of ALT increment. The dose-response HRs of all-cause mortality, cardiovascular (CV) disease-related mortality, and cancer-related mortality were 0.91 (0.88–0.94), 0.91 (0.85–0.96), 0.92 (0.86–0.98) respectively per 5 U/l of ALT elevation, with insignificant heterogeneity in the older population. There was an approximate decrease of 4‰ observed on HRs of all-cause, CV-related, and cancer-related mortality followed with one year's increment through meta-regression (all P<0.05).

Conclusions

The ALT-mortality association was inconsistent and seems particularly susceptible to age after synthesizing the previous prospective studies. In terms of the age, ALT activity was more valuable in predicting mortality in the older population; extremely low ALT levels indicated a higher all-cause, CV-related, and cancer-related mortality. ALT activity may therefore be a useful biomarker when predicting the long-term survival of elderly patients.

Functional status determines postoperative outcomes in elderly patients undergoing hepatic resections

BACKGROUND

With the aging population and increasing incidence of hepatic malignancies in elderly patients, establishing the safety of hepatic resections is crucial. The present study investigates early postoperative morbidity and mortality in elderly patients undergoing hepatic resection using a nationally validated database.

METHODS

The National Surgical Quality Improvement Program Participant User Files (NSQIP-PUF) for 2005-2009 were used for the retrospective analysis of all patients undergoing hepatic resection. The primary outcome measures were 30-day postoperative mortality, overall complication rate, and serious complication rate. The primary predictor variable was patient age, which was treated as a dichotomous variable (age ≤ 70 years, age ≥ 70 years).

RESULTS

Five thousand seven hundred six patients were included in the final analysis, 1,280 of which were ≥ 70 years of age. Thirty-day postoperative mortality (≤ 70 years 1.9% vs. ≥ 70 years 4.5%, P < 0.0001), serious complications (≤ 70 years 15.2% vs. ≥ 70 years 18.4%, P < 0.006) and overall complications (≤ 70 years 23.1% vs. ≥ 70 years 26.6%, P < 0.01) were more common in the elderly group. Elderly patients had significantly more wound infections, pneumonia, prolonged ventilator support, unplanned re-intubations, renal failure, strokes, myocardial infarction, cardiac arrests, and septic shock. The median length of hospitalization was also significantly longer in the elderly.

CONCLUSIONS

This study shows significantly higher complication rates and mortality following hepatic resections in elderly patients. These findings should be taken into account when considering hepatectomy in this population.

Lower calcineurin inhibitor doses in older compared to younger kidney transplant recipients yield similar troughs

The number of older adults undergoing kidney transplantation has increased, yet little is known about calcineurin inhibitor (CNI) metabolism in this group. We studied CNI troughs and doses to determine if there were age-related differences in metabolism and dose requirements. We studied 348 young (18-34 years), 1831 middle (35-64 years) and 374 older (65-84 years) adult kidney transplant recipients enrolled in a seven-center prospective study. Troughs were obtained from each patient 2×/week in weeks 1-8 and 2×/month in months 3-6. A multivariable linear-mixed model examined the effect of age on log dose and weight normalized troughs. Older recipients had higher normalized tacrolimus troughs than middle or young age adults despite receiving doses a median of 1-2 mg/day lower. Age and CYP3A5*1 genotype had the largest effect on tacrolimus troughs. Older recipients also had higher normalized cyclosporine troughs than middle or young adults despite receiving median doses 100 mg/day lower. After normalization for dose and weight, CNI troughs were more than 50% higher in older adults than young adults. These data support age-related changes in CNI metabolism. Further studies are needed to determine optimal dosing of CNIs in the elderly.

Serotonin: from top to bottom

Serotonin is a monoamine neurotransmitter, which is phylogenetically conserved in a wide range of species from nematodes to humans. In mammals, age-related changes in serotonin systems are known risk factors of age-related diseases, such as diabetes, faecal incontinence and cardiovascular diseases. A decline in serotonin function with aging would be consistent with observations of age-related changes in behaviours, such as sleep, sexual behaviour and mood all of which are linked to serotonergic function. Despite this little is known about serotonin in relation to aging. This review aims to give a comprehensive analysis of the distribution, function and interactions of serotonin in the brain; gastrointestinal tract; skeletal; vascular and immune systems. It also aims to demonstrate how the function of serotonin is linked to aging and disease pathology in these systems. The regulation of serotonin via microRNAs is also discussed, as are possible applications of serotonergic drugs in aging research and age-related diseases. Furthermore, this review demonstrates that serotonin is potentially involved in whole organism aging through its links with multiple organs, the immune system and microRNA regulation. Methods to investigate these links are discussed.

Using genetic and clinical factors to predict tacrolimus dose in renal transplant recipients

AIMS

Tacrolimus has a narrow therapeutic window and shows significant interindividual difference in dose requirement. In this study we aim to first identify genetic factors that impact tacrolimus dose using a candidate gene association approach, and then generate a personalized algorithm combining identified genetic and clinical factors to predict individualized tacrolimus dose.

MATERIALS & METHODS

We screened 768 SNPs in 15 candidate genes in metabolism, transport and calcineurin inhibition pathways of tacrolimus, for association with tacrolimus dose in a discovery cohort of 96 patients.

RESULTS

Four polymorphisms in CYP3A5 and one polymorphism in CYP3A4 were identified to be significantly associated with tacrolimus stable dose (p < 8.46 × 10(-5)). The same SNPs were identified when dose-normalized trough tacrolimus concentration was analyzed. The CYP3A5*1 allele was associated with significantly higher stable dose, bigger dose increase, higher risk of being underdosed and lower incidence of post-transplant hyperlipidemia. ABCB1 polymorphisms were not associated with stable dose. No significant difference was found between CYP3A5 expressers and nonexpressers in incidence of acute rejection and time to first rejection. Age, ethnicity and CYP3A inhibitor use could predict 30% of tacrolimus dosing variability. Adding the identified genetic polymorphisms to the algorithm increased the predictability to 58%. In two validation cohorts of 77 and 64 patients, the algorithm containing both genetic and clinical factors produced correlation coefficients of 0.63 and 0.42, respectively. This algorithm gave a prediction of the stable doses closer to the actual doses when compared with another algorithm based only on the CYP3A5 genotype.

CONCLUSION

CYP3A5 genotype is the most significant genetic factor that impacts tacrolimus dose among the genes studied. This study generated the first pharmacogenomics model that predicts tacrolimus stable dose based on age, ethnicity, genotype and comedication use. Our results highlight the importance of incorporating both genetic and clinical, demographic factors into dose prediction.

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

Hepatic clearance plays a key role in determining the systemic exposure of drugs and metabolites, which in turn has a major effect on variability in the beneficial and adverse effects of medicines. Aging results in a number of significant changes in the human liver including reductions in liver blood flow, size, drug-metabolizing enzyme content, and pseudocapillarization. Drug metabolism is also influenced by comorbid disease, frailty, concomitant medicines, and (epi)genetics. These changes have the potential to alter the hepatic clearance of drugs but need to be interpreted in the context of the pharmacokinetic (and pharmacodynamic) characteristics of the drug of interest. There is growing evidence that the age-related changes in the liver not only result in a decrease in the hepatic clearance of unbound drug but also influence variability in response to medicines in older people.

Clinical implications of changes in hepatic drug metabolism in older people

Prescribing for older people is challenging because of the paucity of clinical trial evidence of therapeutic benefit in this population and the presence of evidence that older people are at increased risk of adverse drug reactions. The outcomes of pharmacotherapies in older people depend on age-related changes in both pharmacokinetics and pharmacodynamics. Of the pharmacokinetic changes, those in hepatic metabolism are the most significant. Recent advances in biogerontology have improved our understanding of changes that occur in hepatic pharmacokinetics in older people. Knowledge of age-related changes in hepatic metabolism can guide prescribing and help reduce the risk–benefit ratio of using medications in older people.

Quality indicators for in-hospital pharmaceutical care of Dutch elderly patients: development and validation of an ACOVE-based quality indicator set

BACKGROUND

In 2001, the ACOVE (Assessing Care Of Vulnerable Elders) quality indicators (QIs) were developed in the US to measure the quality of care of vulnerable elderly patients. However, the ACOVE QI set was developed mainly to assess the overall quality of care of community-dwelling vulnerable elders (as opposed to hospitalized elderly). Therefore, they need to be adapted when used in a non-US hospital setting. In addition, the ACOVE QIs depend on patient and caretaker interviews to assess the quality of care.

OBJECTIVE

The aim of this study was to develop and validate a set of explicitly phrased QIs to measure (without the need for interviews) the quality of pharmaceutical care of elderly hospitalized patients in the Netherlands.

STUDY DESIGN

The QI set was developed based on the ACOVE QIs, Dutch national guidelines, evidence from the literature and expert opinion. The QI set focused on in-hospital pharmaceutical care and was evaluated in terms of whether the QIs were able to assess the quality of care using medical records and a hospital information system. In three review rounds, the QI set was adapted and judged on face and content validity. The feasibility of implementation of the QI set and inter-rater reliability were determined.

SETTING

The study was conducted between September 2007 and August 2008 in a tertiary 1002-bed university hospital. RESEARCH TEAM: Two pharmacists were responsible for the selection and adaptation of QIs. An internist-geriatrician, a physician with experience in quality assurance and internal medicine and a senior hospital pharmacist formed the expert panel responsible for reviewing the QIs.

MEASUREMENTS

Fleiss' κ values and the intraclass correlation coefficient were calculated for inter-rater reliability.

RESULTS

An 87-item QI set was accepted by the expert panel. Of this set, 49 QIs were based on ACOVE QIs and 38 QIs were newly added. The QI set demonstrated excellent inter-rater reliability and good feasibility.

CONCLUSIONS

We developed a valid and reliable set of QIs to efficiently assess the quality of the in-hospital pharmaceutical care provided to elderly Dutch patients.

Influence of CYP2C19 and ABCB1 polymorphisms on plasma concentrations of lansoprazole enantiomers after enteral administration

An intraoral annihilation enteric-coated preparation of lansoprazole is often administered via intestinal fistula. The purpose of this study was to determine the plasma concentrations of lansoprazole enantiomers after enteral administration in subjects with cytochrome P4502C19 (CYP2C19) and ABCB1 C3435T genotypes. Fifty-one patients who underwent a curative oesophagectomy for oesophageal cancer were enrolled in this study. After a single enteral dose of racemic lansoprazole (30 mg), plasma concentrations of lansoprazole enantiomers were measured 4 h post-dose (C(4h)). There were significant differences in the C(4h) of (R)- and (S)-lansoprazole and the R/S-enantiomer ratio for three CYP2C19 genotype groups (*1/*1, *1/*2 ± *1/*3, and *2/*2 ± *2/*3 ± *3/*3 (poor metabolizers (PMs)), but not the ABCB1 C3435T genotypes. In a stepwise forward selection multiple regression analysis, the C(4h) of (R)- and (S)-lansoprazole were associated with CYP2C19 PMs (p = 0.0005 and < 0.0001 respectively) and age (p = 0.0040 and 0.0121 respectively), while the R/S-enantiomer ratio was associated with CYP2C19*1/*1 (p = 0.0191) and CYP2C19 PMs (p = 0.0426). Direct administration to the jejunum is unaffected by residence time in the stomach and the gastric emptying rate. With enteral administration, CYP2C19 phenotyping of patients using the lansoprazole R/S enantiomer index at C(4h) could be possible.

Serotonin reverts age-related capillarization and failure of regeneration in the liver through a VEGF-dependent pathway

The function of the liver is well-preserved during the aging process, although some evidence suggests that liver regeneration might be impaired with advanced age. We observed a decreased ability of the liver to restore normal volume after partial hepatectomy in elderly mice, and we identified a pathway that rescued regeneration and was triggered by serotonin. 2,5-dimethoxy-4-iodoamphetamine (DOI), a serotonin receptor agonist, reversed the age-related pseudocapillarization of old liver and improved hepatosinusoidal blood flow. After hepatectomy, the open fenestrae were associated with a restored attachment of platelets to endothelium and the initiation of a normal regenerative response, including the up-regulation of essential growth mediators and serotonin receptors. In turn, hepatocyte proliferation recovered along with regain of liver volume and animal survival. DOI operates through the release of VEGF, and its effects could be blocked with anti-VEGF antibodies both in vitro and in vivo. These results suggest that pseudocapillarization in the aged acts as a barrier to liver regeneration. DOI breaks this restraint through an endothelium-dependent mechanism driven by VEGF. This pathway highlights a target for reversing the age-associated decline in the capacity of the liver to regenerate.

The elderly as a sensitive population in environmental exposures: making the case

The US population is aging. CDC has estimated that 20% of all Americans will be 65 or older by the year 2030. As a part of the aging process, the body gradually deteriorates and physiologic and metabolic limitations arise. Changes that occur in organ anatomy and function present challenges for dealing with environmental stressors of all kinds, ranging from temperature regulation to drug metabolism and excretion. The elderly are not just older adults, but rather are individuals with unique challenges and different medical needs than younger adults. The ability of the body to respond to physiological challenge presented by environmental chemicals is dependent upon the health of the organ systems that eliminate those substances from the body. Any compromise in the function of those organ systems may result in a decrease in the body's ability to protect itself from the adverse effects of xenobiotics. To investigate this issue, we performed an organ system-by-organ system review of the effects of human aging and the implications for such aging on susceptibility to drugs and xenobiotics. Birnbaum (1991) reported almost 20 years ago that it was clear that the pharmacokinetic behavior of environmental chemicals is, in many cases, altered during aging. Yet, to date, there is a paucity of data regarding recorded effects of environmental chemicals on elderly individuals. As a result, we have to rely on what is known about the effects of aging and the existing data regarding the metabolism, excretion, and adverse effects of prescription medications in that population to determine whether the elderly might be at greater risk when exposed to environmental substances. With increasing life expectancy, more and more people will confront the problems associated with advancing years. Moreover, although proper diet and exercise may lessen the immediate severity of some aspects of aging, the process will continue to gradually degrade the ability to cope with a variety of injuries and diseases. Thus, the adverse effects of long-term, low-level exposure to environmental substances will have a longer time to be manifested in a physiologically weakened elderly population. When such exposures are coupled with concurrent exposure to prescription medications, the effects could be devastating. Public health officials must be knowledgeable about the sensitivity of the growing elderly population, and ensure that the use of health guidance values (HGVs) for environmental contaminants and other substances give consideration to this physiologically compromised segment of the population.

No impact of age on dose-adjusted pharmacokinetics of tacrolimus, mycophenolic acid and prednisolone 1 month after renal transplantation

PURPOSE

The purpose of the study was to assess the impact of age on the pharmacokinetics of immunosuppressive drugs.

METHODS

One hundred and ten renal transplant recipients, including 12 elderly patients over 60 years of age, 57 middle-aged patients between 40 and 59 years and 41 young adult patients 20 to 39 years of age were studied. To evaluate dose-adjusted pharmacokinetics and cytochrome P450 (CYP) 3A5 pharmacogenetics, the concentrations of tacrolimus, mycophenolic acid (MPA), MPA glucuronide (MPAG) and prednisolone were measured at 1 month post-transplantation.

RESULTS

There were no differences in dose (D) and body weight (BW)-adjusted pharmacokinetic parameters of tacrolimus among the three groups. D/BW-adjusted C(max), C(0) and AUC(0-12) values of tacrolimus were significantly greater in patients with the CYP3A5*3/*3 genotype than in those with the CYP3A5*1 allele in young and middle-aged patients as previously reported, but not in the elderly. There were no significant differences in the D-adjusted pharmacokinetics of prednisolone and MPA among the three groups.

CONCLUSION

The aging process itself may have a small effect on the pharmacokinetics of tacrolimus, MPA, or prednisolone. However, a larger number of subjects need to be studied to confirm the impact of age on the CYP3A5 pharmacogenetics of tacrolimus in the elderly.

Potential interactions of central nervous system drugs used in the elderly population

OBJECTIVE: To describe the use of CNS drugs and to identify the most frequently observed potential drug interactions in the elderly living in Southern Brazil. METHODS: A population-based, transversal and observational study was carried out during 2006-2007. Four hundred and eighty elderly individuals of both genders were randomly recruited and interviewed. A validated pharmacotherapeutic questionnaire and the Micromedex® Healthcare Series were utilized to analyze potential drug interactions. A severity rating scale employing the categories of "mild", "moderate" and "severe" was used to describe the interactions. RESULTS: A population of elderly living in Southern Brazil was interviewed and 98 reported using CNS drugs, 74.5% female and 25.5% male. Out of these patients, 32.0% reported severe or moderate pharmacological interactions related to the use of other drugs. Alprazolam and imipramine were reported to potentially interact with tobacco. Twenty potential moderate drug/ethanol interactions were found. The potential drug/caffeine interactions were classified as mild on the severity scale. CONCLUSION: Elderly being prescribed drugs that act on the CNS should be closely monitored, and furthermore, should be warned against potential drug-drug, drug-ethanol, and drug-tobacco interactions.

Free-radical scavenging and mitochondrial antioxidant activities of Reishi-Ganoderma lucidum (Curt: Fr) P. Karst and Arogyapacha-Trichopus zeylanicus Gaertn extracts

Endogenous damage to mitochondrial DNA by free radicals is believed to be a major contributory factor to aging. The current study examined the effects of the extracts of two important anti-fatigue and rejuvenating medicinal herbs Ganoderma lucidum and Trichopus zeylanicus for their free-radical scavenging property and for their effects on liver mitochondrial antioxidant activity in aged mice. Both extracts were administrated orally to aged BALB/c mice at doses of 50 and 250 mg/kg body weight for 15 days. Super oxide dismutase (SOD) and catalase (CAT) activity and levels of reduced glutathione (GSH) and lipid peroxidation as equivalents of malondialdehyde (MDA) formed were determined. Groups of young mice and aged mice (more than 15 months old) were taken as controls. Both G. lucidum and T. zeylanicus extracts increased antioxidant status in liver mitochondria of aged mice compared with the aged control. Higher levels of GSH, increased activity of SOD and CAT, and decreased level of MDA in both treated groups compared with the controls were evident. Both extracts possessed significant 2,2-diphenyl-1-picrylhydrazil (DPPH), 2, 2'-azinobis (3-ethylbenzothiazolin-6-sulphonic acid) (ABTS) radical scavenging activities and ferric reducing antioxidant power (FRAP). The DPPH, ABTS, and FRAP activities were higher in G. lucidum extract than in T. zeylanicus. G. lucidum extract also showed superoxide and hydroxyl radical scavenging activities. T. zeylanicus had significantly higher lipid peroxidation inhibiting activity than G. lucidum. Thus, we conclude that the antioxidative effect of the G. lucidum extract was higher than that of T. zeylanicus. Our findings suggest a potential therapeutic efficacy of G. lucidum extract to protect against aging and to a certain extent against age-related degenerative diseases.