Geriatric Pharmacology

Pharmacokinetic and Pharmacodynamic Considerations in Relation to Calcineurin Usage in Elderly Kidney Transplant Recipients

This review summarizes how possible age-related changes in tacrolimus and cyclosporine pharmacokinetics and pharmacodynamics may influence drug dosing and monitoring in the elderly, and highlights how micro-sampling may be useful in this cohort in the future. Advancing biological age leads to physiological changes that can affect drug absorption, distribution, metabolism and excretion, as well as immune system responsiveness. Some studies have shown that elderly recipients may have higher dose-adjusted exposure and/or lower clearance of the calcineurin inhibitors, suggesting that doses may need to be lowered in elderly recipients. Only one study has examined how aging effects drug target enzyme activity and demonstrated that age does not correlate with the calcineurin inhibitor half-maximal inhibitory concentration. Several studies have shown elderly kidney transplant recipients have increased risk of both morbidity and mortality, compared to younger adults due to increased susceptibility to immunosuppressant side effects, particularly cardiovascular disease, infection and malignancy. Current immunosuppressant dosing and monitoring protocols often make no adjustments for age. 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. Blood draw by micro-sampling may be useful for drug monitoring in this cohort in the future, as blood collection is minimally invasive and less painful than venepuncture. Micro-sampling could also make further pharmacokinetic, pharmacodynamics and outcome studies in the elderly more feasible.

Older Women and Opioid Analgesia after Breast Cancer Surgery

PURPOSE

To explore which factors influence opioid analgesia use in older women during the 48-hour period after hospital discharge following initial breast cancer surgery.

DESIGN

This cross-sectional, descriptive study involved a cohort (n = 57) of older women recruited for a larger study of breast cancer patients.

METHODS

We gathered patient-reported data pertinent to perioperative and post-discharge pain control. Data were analyzed using linear regression to explore those characteristics that had the greatest influence on the amount of post-discharge opioid analgesia required.

RESULTS

After hospital discharge, 29 older women (51%) with breast cancer avoided opioid analgesia for various reasons. The number of prescribed opioid tablets each woman self-administered determined the total dosage of analgesia required 48 hours post-discharge.

CONCLUSIONS

The majority of this sample of older women with early-stage breast cancer experienced adequate pain relief after surgery and required little or no postoperative or postdischarge opioid analgesia. Optimization of the pain control experience for older women with breast cancer requires thorough pain assessment from diagnosis through survivorship through the end of life. This can be achieved by equipping women in this population to advocate for their pain control needs in real time. Future studies that elucidate preferences, beliefs, and current pain control practices before, during, and after breast cancer surgery will improve safety and efficacy of pain control for this fast-growing population.

Pharmacokinetics and Safety of Chiglitazar, a Peroxisome Proliferator-Activated Receptor Pan-Agonist, in Patients < 65 and ≥ 65 Years With Type 2 Diabetes

The effect of age on the pharmacokinetics and safety of chiglitazar was evaluated in patients < 65 and ≥ 65 years with type 2 diabetes mellitus (T2DM). A total of 20 T2DM patients (<65 vs ≥65 years 1:1) completed the study. Patients received multiple doses of 48 mg chiglitazar once daily for 7 days consecutively. After the first dosing, chiglitazar maximum plasma concentration (C_max ) and area under the plasma concentration-time curve (AUC) in patients ≥ 65 years were similar to those observed in patients < 65 years, with the geometric mean ratio (GMR) for C_max and AUC being 97.22% and 96.83%, respectively. No significant difference was observed in C_max (GMR, 97.23%) in the steady state. Compared with the patients < 65 years, a slight increase (8%-13%) of AUC was observed in the patients ≥ 65 years after multiple doses. Chiglitazar was generally well tolerated following multiple doses in both age groups. In conclusion, there were no significant clinical influences on the pharmacokinetic properties and safety profiles of chiglitazar between patients with T2DM < 65 and ≥ 65 years, indicating that in the future it is not required to adjust the dosing regimen by age for T2DM patients ≥ 65 years.

Clinical, clinicopathologic, and hepatic histopathologic features associated with probable ketoconazole-induced liver injury in dogs: 15 cases (2015-2018)

OBJECTIVE

To characterize clinical, clinicopathologic, and hepatic histopathologic features and outcome for dogs with probable ketoconazole-induced liver injury.

ANIMALS

15 dogs with suspected ketoconazole-induced liver injury that underwent liver biopsy.

PROCEDURES

Medical record data were summarized regarding signalment, clinical signs, clinicopathologic and hepatic histopathologic findings, concurrent medications, ketoconazole dose, treatment duration, and outcome.

RESULTS

Median age and body weight were 8.2 years (range, 5 to 15 years) and 13.0 kg (28.6 lb; range, 8.2 to 38.0 kg [18.0 to 83.6 lb]), respectively. The most common breed was Cocker Spaniel (n = 5). All dogs received ketoconazole to treat cutaneous Malassezia infections. Median daily ketoconazole dose was 7.8 mg/kg (3.5 mg/lb; range, 4.4 to 26.0 mg/kg [2.0 to 11.8 mg/lb]), PO. Treatment duration ranged from 0.3 to 100 cumulative weeks (intermittent cyclic administration in some dogs); 6 dogs were treated for ≤ 10 days. Common clinical signs included lethargy, anorexia, and vomiting. All dogs developed high serum liver enzyme activities. Hepatic histopathologic findings included variable lobular injury, mixed inflammatory infiltrates, and conspicuous aggregates of ceroid-lipofuscin-engorged macrophages that marked regions of parenchymal damage. Five dogs developed chronic hepatitis, including 3 with pyogranulomatous inflammation. Of the 10 dogs reported to have died at last follow-up, survival time after illness onset ranged from 0.5 to 165 weeks, with 7 dogs dying of liver-related causes.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings for dogs with hepatotoxicosis circumstantially associated with ketoconazole treatment suggested proactive monitoring of serum liver enzyme activities is advisable before and sequentially after initiation of such treatment.

Bioelectrical impedance analysis of body composition for the anesthetic induction dose of propofol in older patients

Background

Older people are currently the fastest growing segment of the worldwide population. The present study aimed to estimate propofol dose in older patients based on size descriptors measured by bioelectrical impedance analysis (BIA).

Methods

A cross sectional study in adult and older patients with body mass index equal to or lower than 35 kg/m² was carried out. BIA and Clinical Frail Scale scoring were performed during pre-operative evaluation. Propofol infusion was started at 2000 mg/h until loss of consciousness (LOC) which was defined by “loss of eye-lash reflex” and “loss of response to name calling”. Total dose of propofol at LOC was recorded. Propofol plasma concentration was measured using gas chromatography/ion trap-mass spectrometry.

Results

Forty patients were enrolled in the study. Total propofol dose required to LOC was lower in Age ≥ 65 group and a higher plasma propofol concentration was measured in this group. 60% of old patients were classified as “apparently vulnerable” or “frail” and narrow phase angle values were associated with increasing vulnerability scores. In the Age ≥ 65 group, the correlation analysis showed that the relationship between propofol dose and total body weight (TBW) scaled by the corresponding phase angle value is stronger than the correlation between propofol dose and TBW or fat free mass (FFM).

Conclusions

This study demonstrates that weight-based reduction of propofol is suitable in older patients; however FFM was not seen to be more effective than TBW to predict the propofol induction dose in these patients. Guiding propofol induction dose according to baseline frailty score should also be considered to estimate individualized dosage profiles. Determination of phase angle value appears to be an easy and reliable tool to assess frailty in older patients.

Trial registration

ClinicalTrials.gov Identifier: NCT02713698. Registered on 23 February 2016.

Preoperative Management of the Geriatric Patient: Frailty and Cognitive Impairment Assessment

As the population ages, more geriatric patients will be presenting for surgical procedures. Preoperative evaluation seeks to assess patients for geriatric syndromes: frailty, sarcopenia, functional dependence, and malnutrition. Age-related changes in physiology increase risk for central nervous system, cardiovascular, pulmonary, renal, hepatic, and endocrine morbidity and mortality. Identification of various comorbidities allows for preoperative optimization and for opportunities for intervention including nutritional supplementation and prehabilitation, which may improve postoperative outcomes.

A Retrospective Observational Study of Anesthetic Induction Dosing Practices in Female Elderly Surgical Patients: Are We Overdosing Older Patients?

BACKGROUND/OBJECTIVES

Despite guidelines suggesting a 25-50 % reduction in induction doses of intravenous anesthetic agents in the elderly (≥65 years), we hypothesized that practitioners were not sufficiently correcting drug administration for age, contributing to an increased incidence of hypotension in older patients undergoing general anesthesia.

STUDY DESIGN

We conducted a retrospective, observational study in a tertiary-care academic hospital. The study included 768 female patients undergoing gynecologic surgeries who received propofol-based induction of general anesthesia.

MAIN OUTCOME MEASURES

Weight-adjusted anesthetic induction dosing, age-associated differences in dosing by ASA-PS (American Society of Anesthesiology-Physical Status), and hemodynamic outcomes between younger (18-64 years, n = 537) and older (≥65 years, n = 231) female patients were analyzed.

RESULTS

Older patients received lower doses of propofol and midazolam than younger patients (propofol: 2.037 ± 0.783 vs 2.322 ± 0.834 mg/kg, p < 0.001; midazolam: 0.013 ± 0.014 vs 0.023 ± 0.042 mg/kg, p < 0.001). However, practitioners still consistently exceeded the FDA recommended dose (1-1.5 mg/kg) of propofol for elderly patients. There was no significant difference in the doses of fentanyl administered between the two age groups (1.343 ± 0.744 vs 1.363 ± 0.763 μg/kg, p = 0.744), and doses of fentanyl in older patients exceeded the recommended dose (0.5-1.0 μg/kg). Corresponding to observed overdosing of induction agents, older patients experienced larger decreases in post-induction blood pressure and were more likely to receive vasopressor therapy.

CONCLUSIONS

Anesthetic induction doses of fentanyl and propofol were not sufficiently corrected in older patients in accordance with recommendations. Significantly greater frequency of post-induction hypotension occurred amongst older patients. Quality improvement efforts may lead to improved outcomes in this vulnerable population.

A Pilot Analysis of the Association Between Types of Monitored Anesthesia Care Drugs and Outcomes in Transfemoral Aortic Valve Replacement Performed Without General Anesthesia

OBJECTIVE

The types of agents used for monitored anesthesia care (MAC) and their possible differential effects on outcomes have received less study despite increased use over general anesthesia (GA) in transfemoral aortic valve replacements (TAVRs). In this pilot analysis of patients undergoing TAVR using MAC, the authors described the anesthetic agents used and sought to investigate the possible association of anesthetic agent choice with outcomes and the extent to which total weight and time-adjusted doses of anesthetics declined with increasing 10-year age increments.

DESIGN

Retrospective observational study.

SETTING

Tertiary teaching hospital.

PARTICIPANTS

Ninety-three participants scheduled to undergo TAVR, with a primary plan of conscious sedation between November 2014 and June 2016, were included.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Types of MAC were divided into 4 primary groups, but 2 groups were focused: propofol (n = 39) and dexmedetomidine plus propofol (n = 34). Conversion to GA occurred in 6 participants (6.45%) and was not associated with the type of sedation received. The authors also compared patients who received dexmedetomidine with those who did not in accordance with their a priori analytic plan. There were no associations between the use of dexmedetomidine and postoperative delirium or intensive care unit/hospital length of stay. No significant trends in medication dose adjustments were seen across increasing 10-year age increments.

CONCLUSIONS

A wide breadth of MAC medications is in use among TAVR patients and does not support differences in outcomes. Despite recommendations to reduce anesthetic drug dosing in the elderly, no significant trends in dose reduction with increasing age were noted.

Does intravenous induction dosing among patients undergoing gastrointestinal surgical procedures follow current recommendations: a study of contemporary practice

STUDY OBJECTIVE

It is recommended to correct intravenous induction doses by up to 50% for patients older than 65 years. The objectives were to determine (a) the degree to which anesthesia providers correct induction doses for age and (b) additionally adjust for American Society of Anesthesiologists physical status (ASA-PS) class (severity of illness) and (c) whether postinduction hypotension is more common among patients aged >65.

DESIGN

Retrospective chart review.

SETTING

Academic medical center.

PATIENTS

A total of 1869 adult patients receiving general anesthesia for GI surgical procedures from February 2013 to January 2014.

MEASUREMENTS

Patients were divided into 3 age groups (age <65, 65-79, ≥80 years) and then further stratified into ASA-PS class (I/II vs III/IV). Multiple pairwise comparisons were conducted using Welch t tests for continuous variables to determine whether dosing was different for the older groups vs the younger group; separate analyses were performed within and across ASA-PS class. This approach was also used to determine differences in mean arterial pressure change in the older groups vs the younger group, whereas the rates of hypotension among different age groups were compared by Cochran-Armitage trend test.

MAIN RESULTS

No significant decrease in dosing between age groups was observed for fentanyl and midazolam. For propofol, there was a significantly lower dosing for older patients: 17% for patients aged 65-79 and 29% for those aged >80, which was still in less than the recommendations. An inverse relationship was observed between propofol dosing and ASA-PS class, but no consistent relationship was noted for fentanyl and midazolam. There were a significantly larger drop in mean arterial pressure and a greater likelihood of hypotension following induction in patients aged 65-79 years and >80 years as compared with those aged <65 years.

CONCLUSIONS

This study shows that the administered dose of anesthetic induction agents is significantly higher than that recommended for patients older than 65 years. This failure to age-adjust dose may contribute to hypotensive episodes.