The effect of age on the pharmacokinetics and pharmacodynamics of midazolam

Efficacy of a melatonin receptor agonist and orexin receptor antagonists in preventing delirium symptoms in the olderly patients with stroke: a retrospective study

BACKGROUND

Post-stroke delirium affects between 24% and 43% of patients, and negatively impacts patient outcomes. Recently, research attention has been on preventive interventions for delirium, with melatonin receptor agonists and orexin receptor antagonists reported to be effective in preventing delirium in intensive care unit patients. However, the efficacy of these agents in preventing post-stroke delirium remain unclear. This study examined the efficacy of ramelteon, suvorexant, and lemborexant in preventing post-stroke delirium symptoms in patients with stroke.

METHODS

A retrospective survey of medical records was conducted for patients with stroke aged > 75 years at Kyoto University Hospital from October 2021 to March 2023. Patients who received ramelteon, suvorexant, or lemborexant on admission and the following day were classified into the consecutive administration group, whereas those who did not were classified into the non-consecutive administration group. The primary outcome was an increase in the number of positive items in the delirium screening tool over 7 days.

RESULTS

Of the 104 patients, 33 and 71 were in the consecutive and non-consecutive administration groups, respectively. Fewer patients in the consecutive administration group had an increase in the number of positive items than in the other group (6% vs. 21%). Patients in the consecutive administration group significantly less often had an increase in the number of positive items in the delirium screening tool (P = 0.05; hazard ratio, 0.27; 95% confidence interval, 0.10-0.75).

CONCLUSIONS

This study revealed that early administration of a melatonin receptor agonist or orexin receptor antagonists may effectively prevent post-stroke delirium in older patients.

Optimising the oral midazolam dose for premedication in people with intellectual disabilities and/or autism spectrum disorder

BACKGROUND

In people with intellectual disabilities and/or autism spectrum disorder, oral midazolam (OM) is very effective as premedication for facilitating medical treatment. In this retrospective study, we investigated the optimal dosage of OM for premedication.

METHODS

Patients with intellectual disability and/or autism spectrum disorder who were given OM as a premedication were selected from anaesthesia records. The primary outcome variable was the dose of OM (mg/kg) required to produce an adequate sedation.

RESULTS

The mean OM dose required was 0.32 ± 0.10 mg/kg. The required OM dose decreased significantly as age and weight increased, and age and weight were also shown to be significantly associated with the dose of OM in the multivariate linear regression analysis.

CONCLUSION

The dosage of OM to achieve adequate sedation should decrease as the patient ages. Furthermore, adequate sedation can be achieved with even lower doses of OM in obese people.

Preoperative Midazolam and Patient-Centered Outcomes of Older Patients: The I-PROMOTE Randomized Clinical Trial

Importance

The effect of oral midazolam premedication on patient satisfaction in older patients undergoing surgery is unclear, despite its widespread use.

Objective

To determine the differences in global perioperative satisfaction in patients with preoperative administration of oral midazolam compared with placebo.

Design, Setting, and Participants

This double-blind, parallel-group, placebo-controlled randomized clinical trial was conducted in 9 German hospitals between October 2017 and May 2019 (last follow-up, June 24, 2019). Eligible patients aged 65 to 80 years who were scheduled for elective inpatient surgery for at least 30 minutes under general anesthesia and with planned extubation were enrolled. Data were analyzed from November 2019 to December 2020.

Interventions

Patients were randomized to receive oral midazolam, 3.75 mg (n = 309), or placebo (n = 307) 30 to 45 minutes prior to anesthesia induction.

Main Outcomes and Measures

The primary outcome was global patient satisfaction evaluated using the self-reported Evaluation du Vécu de l'Anesthésie Generale (EVAN-G) questionnaire on the first postoperative day. Key secondary outcomes included sensitivity and subgroup analyses of the primary outcome, perioperative patient vital data, adverse events, serious complications, and cognitive and functional recovery up to 30 days postoperatively.

Results

Among 616 randomized patients, 607 were included in the primary analysis. Of these, 377 (62.1%) were male, and the mean (SD) age was 71.9 (4.4) years. The mean (SD) global index of patient satisfaction did not differ between the midazolam and placebo groups (69.5 [10.7] vs 69.6 [10.8], respectively; mean difference, -0.2; 95% CI, -1.9 to 1.6; P = .85). Sensitivity (per-protocol population, multiple imputation) and subgroup analyses (anxiety, frailty, sex, and previous surgical experience) did not alter the primary results. Secondary outcomes did not differ, except for a higher proportion of patients with hypertension (systolic blood pressure ≥160 mm Hg) at anesthesia induction in the placebo group.

Conclusion and Relevance

A single low dose of oral midazolam premedication did not alter the global perioperative patient satisfaction of older patients undergoing surgery or that of patients with anxiety. These results may be affected by the low dose of oral midazolam. Further trials-including a wider population with commonplace low-dose intravenous midazolam and plasma level measurements-are needed.

Trial Registration

ClinicalTrials.gov Identifier: NCT03052660.

Ligand-Free Signaling of G-Protein-Coupled Receptors: Physiology, Pharmacology, and Genetics

G-protein-coupled receptors (GPCRs) are ubiquitous sensors and regulators of cellular functions. Each GPCR exists in complex aggregates with multiple resting and active conformations. Designed to detect weak stimuli, GPCRs can also activate spontaneously, resulting in basal ligand-free signaling. Agonists trigger a cascade of events leading to an activated agonist-receptor G-protein complex with high agonist affinity. However, the ensuing signaling process can further remodel the receptor complex to reduce agonist affinity, causing rapid ligand dissociation. The acutely activated ligand-free receptor can continue signaling, as proposed for rhodopsin and μ opioid receptors, resulting in robust receptor activation at low agonist occupancy with enhanced agonist potency. Continued receptor stimulation can further modify the receptor complex, regulating sustained ligand-free signaling-proposed to play a role in opioid dependence. Basal, acutely agonist-triggered, and sustained elevated ligand-free signaling could each have distinct functions, reflecting multi-state conformations of GPCRs. This review addresses basal and stimulus-activated ligand-free signaling, its regulation, genetic factors, and pharmacological implications, focusing on opioid and serotonin receptors, and the growth hormone secretagogue receptor (GHSR). The hypothesis is proposed that ligand-free signaling of 5-HT2A receptors mediate therapeutic effects of psychedelic drugs. Research avenues are suggested to close the gaps in our knowledge of ligand-free GPCR signaling.

Development of a pharmacokinetic and pharmacodynamic model for intranasal administration of midazolam in older adults: a single-site two-period crossover study

BACKGROUND

Intranasal midazolam can produce procedural sedation in frail older patients with dementia who are unable to tolerate necessary medical or dental procedures during domiciliary medical care. Little is known about the pharmacokinetics and pharmacodynamics of intranasal midazolam in older (>65 yr old) people. The aim of this study was to understand the pharmacokinetic/pharmacodynamic properties of intranasal midazolam in older people with the primary goal of developing a pharmacokinetic/pharmacodynamic model to facilitate safer domiciliary sedation care.

METHODS

We recruited 12 volunteers: ASA physical status 1-2, aged 65-80 yr, and received midazolam 5 mg intravenously and 5 mg intranasally on two study days separated by a 6 day washout period. Concentrations of venous midazolam and 1'-OH-midazolam, Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score, bispectral index (BIS), arterial pressure, ECG, and respiratory parameters were measured for 10 h.

RESULTS

Time to peak effect of intranasal midazolam for BIS, MAP, and SpO₂ were 31.9 (6.2), 41.0 (7.6), and 23.1 (3.0) min, respectively. Intranasal bioavailability was lower compared with intravenous administration (F_abs 95%; 95% confidence interval: 89-100%). A three-compartment model best described midazolam pharmacokinetics following intranasal administration. A separate effect compartment linked to the dose compartment best described an observed time-varying drug-effect difference between intranasal and intravenous midazolam, suggesting direct nose-to-brain transport.

CONCLUSIONS

Intranasal bioavailability was high and sedation onset was rapid, with maximum sedative effects after 32 min. We developed a pharmacokinetic/pharmacodynamic model for intranasal midazolam for older persons and an online tool to simulate changes in MOAA/S, BIS, MAP, and SpO₂ after single and additional intranasal boluses.

CLINICAL TRIAL REGISTRATION

EudraCT (2019-004806-90).

Turn On, Tune In, Turnover! Target Biology Impacts In Vivo Potency, Efficacy, and Clearance

Even though significant efforts have been spent in recent years to understand and define the determinants of in vivo potency and clearance, important pieces of information are still lacking. By introducing target turnover into the reasoning, we open up to further the understanding of central factors important to the optimization of translational dose-concentration-response predictions. We describe (i) new (open model) expressions of the in vivo potency and efficacy parameters, which embody target turnover, binding, and complex kinetics, also capturing full, partial, and inverse agonism and antagonism; (ii) a detailed examination of open models to show what potency and efficacy parameters have in common and how they differ; and (iii) a comprehensive literature review showing that target turnover rate varies with age, species, tissue/subregion, treatment, disease state, hormonal and nutritional state, and day-night cycle. The new open model expression, which integrates system and drug properties, shows the following. Fractional turnover rates rather than the absolute target or ligand-target complex expression determine necessary drug exposure via in vivo potency. Absolute ligand-target expression determines the need of a drug, based on the transduction ρ and in vivo efficacy parameters. The free enzyme concentration determines clearance and maximum metabolic rate. The fractional turnover rate determines time to equilibrium between substrate, free enzyme, and complex.The properties of substrate, target, and the complex demonstrate nonsaturable metabolic behavior at equilibrium. Nonlinear processes, previously referred to as capacity- and time-dependent kinetics, may occasionally have been disequilibria. Finally, the open model may pinpoint why some subjects differ in their demand of drug. SIGNIFICANCE STATEMENT: Understanding the target turnover is a central tenet in many translational dose-concentration-response predictions. New open model expressions of in vivo potency, efficacy parameter, and clearance are derived and anchored onto a comprehensive literature review showing that target turnover rate varies with age, species, tissue/subregion, treatment, disease, hormonal and nutritional state, day-night cycle, and more. Target turnover concepts will therefore significantly impact fundamental aspects of pharmacodynamics and pharmacokinetics, thereby also the basics of drug discovery, development, and optimization of clinical dosing.

Considerations for Satisfactory Sedation during Dental Implant Surgery

Implant surgery is a lengthy dental procedure, and sedation is often used to reduce discomfort. The effectiveness of sedation has traditionally been evaluated in terms of patient and surgeon satisfaction, but the most important goal is not to induce a deep sleep in the patient, but rather to ensure that the surgery is performed safely and as planned. Additionally, adequate pain control is a necessary requirement for patient and surgeon satisfaction. Most patients undergoing implant surgery are middle-aged or older, and a relatively large number of them have cardiovascular disease. Infiltration anesthesia using articaine or lidocaine in combination with adrenaline is widely used, but its use in patients with cardiovascular disease is limited because of adrenaline's effects on the cardiovascular system. The use of long-acting local anesthetics and the potential efficacy of ultrasound-guided jaw nerve block have been investigated to enhance analgesia without resorting to adrenaline. Midazolam and propofol are usually used for sedation, but dexmedetomidine, which causes less respiratory depression, and the ultrashort-acting benzodiazepine remimazolam are emerging as potential alternatives. Monitoring of anesthetic depth using electroencephalography is effective in maintaining a constant level of sedation. In addition, sedation promotes the stabilization of heart rate and blood pressure, reducing the risks associated with adrenaline and allowing for safer management.

Effect of midazolam in autism spectrum disorder: A retrospective observational analysis

BACKGROUND

While midazolam is commonly used as premedication for uncooperative patients, its effects are difficult to predict in patients with autism spectrum disorder for whom abnormalities in gamma-aminobutyric acid have been reported. This study aimed to investigate the influence of autism spectrum disorder on the effect of midazolam when used as premedication.

METHODS

This retrospective observational study was performed between April 2017 and August 2018. Before inducing general anesthesia with sevoflurane for dental treatment, 390 uncooperative patients received premedication with midazolam. Ordinal logistic regression analysis was performed with the Observer's Assessment of Alertness/Sedation score 30 min after premedication as the objective variable. Age, sex, American Society of Anesthesiologists physical status class, premedication route, dose per body weight, presence of specific disorders (autism spectrum disorder, intellectual disability, epilepsy, cerebral palsy, and other psychiatric disorders), and regular benzodiazepine or non-benzodiazepine psychotropic administration were included as explanatory variables. Kendall's rank correlation coefficient was used to assess the correlation between the Observer's Assessment of Alertness/Sedation score and cooperation level (1, obvious negative response; 2, negative response; 3, positive reaction; 4, obvious positive reaction) during admission and inhalation induction. All data were extracted from anesthesia and medical records.

RESULTS

Age (odds ratio 1.437 [95% confidence interval (CI) 1.213-1.708], P < .001), autism spectrum disorder (1.318 [1.079-1.612], P = .007), benzodiazepine medication (0.574 [0.396-0.827], P = .002), and intramuscular route (1.478 [1.137-1.924], P = .004) were significantly associated with the Observer's Assessment of Alertness/Sedation score, while the score was negatively associated with cooperation levels during admission (τ = -0.714, P < .001) and inhalation induction (τ = -0.606, P < .001).

CONCLUSIONS

Patients with autism spectrum disorder may be susceptible to premedication with midazolam; however, regular benzodiazepine administration may reduce the effect.

Risk of fracture in antidepressant users with concurrent use of benzodiazepines: A self-controlled case-series analysis

OBJECTIVE

Despite the fracture risk associated with both antidepressant (AD) medication and benzodiazepines (BDZs), they are commonly prescribed simultaneously. However, studies elucidating the effects of concurrent use of BDZs and ADs on the risk fracture are scant. The objective of this study was to evaluate the risk of fracture associated with concurrent use of BDZs in AD users, using a self-controlled case-series analysis.

METHODS

A self-controlled case-series analysis, in which the participants act as their own control, was conducted using the Korean National Health Insurance Service-National Sample Cohort database (2002-2015). We studied AD users who were prescribed BDZs and diagnosed with a fracture. The risk periods were subdivided into consecutive periods (1-30, 31-60, and > 60 days) after receiving a BDZ. A 2-week pre-exposure period and a 2-week post-exposure period were also included. The incidence rate ratio (IRR) was estimated after adjusting for age and use of co-medications.

RESULTS

A total of 3020 patients were identified during the study period. There was an increased fracture risk in the first 30 days following BDZ use (IRR: 1.88, 95% confidence interval [CI] 1.66-2.12), in the 31-60-day period (1.73, 95% CI 1.48-2.02), and beyond the 60-day period (IRR: 1.68, 95% CI 1.47-1.91). The risks of fracture were greater in men and older patients.

CONCLUSION

The concomitant use of BDZs and ADs was related to a significant increase in fracture risk. AD users should be aware of the fracture risk with concomitant BDZ use, especially for first-time BDZ users and for elderly patients.

Efficacy of Proportional Sedation and Deep Sedation Defined by Sedation Protocols: A Multicenter, Prospective, Observational Comparative Study

PURPOSE

To investigate the efficacy of two types of palliative sedation: proportional and deep sedation, defined by sedation protocols.

METHODS

From a multicenter prospective observational study, we analyzed the data of those patients who received the continuous infusion of midazolam according to the sedation protocol. The primary endpoint was goal achievement at 4 hours: in proportional sedation, symptom relief (Integrated Palliative care Outcome Scale: IPOS ≤ 1) and absence of agitation (modified Richmond Agitation-Sedation Scale: RASS ≤ 0); in deep sedation, the achievement of deep sedation (RASS ≤ -4). Secondary endpoints included deep sedation as a result of proportional sedation, communication capacity (Communication Capacity Scale item 4 ≤ 2), IPOS and RASS scores, and adverse events.

RESULTS

A total of 81 patients from 14 palliative care units were analyzed: proportional sedation (n = 64) and deep sedation (n = 17). At 4 hours, the goal was achieved in 77% (n = 49; 95% confidence interval: 66-87) with proportional sedation; and 88% (n = 15; 71-100) with deep sedation. Deep sedation was necessary in 45% of those who received proportional sedation. Communication capacity was maintained in 34% with proportional sedation and 10% with deep sedation. IPOS decreased from 3.5 to 0.9 with proportional sedation, and 3.5 to 0.4 with deep sedation; RASS decreased from +0.3 to -2.6, and +0.4 to -4.2, respectively. Fatal events related to the treatment occurred in 2% (n = 1) with proportional and none with deep sedation.

CONCLUSION

Proportional sedation achieved satisfactory symptom relief while maintaining some patients' consciousness, and deep sedation achieved good symptom relief while the majority of patients lost consciousness.

Physiologically Based Pharmacokinetic Modelling to Identify Pharmacokinetic Parameters Driving Drug Exposure Changes in the Elderly

BACKGROUND

Medication use is highly prevalent with advanced age, but clinical studies are rarely conducted in the elderly, leading to limited knowledge regarding age-related pharmacokinetic changes.

OBJECTIVE

The objective of this study was to investigate which pharmacokinetic parameters determine drug exposure changes in the elderly by conducting virtual clinical trials for ten drugs (midazolam, metoprolol, lisinopril, amlodipine, rivaroxaban, repaglinide, atorvastatin, rosuvastatin, clarithromycin and rifampicin) using our physiologically based pharmacokinetic (PBPK) framework.

METHODS

PBPK models for all ten drugs were developed in young adults (20-50 years) following the best practice approach, before predicting pharmacokinetics in the elderly (≥ 65 years) without any modification of drug parameters. A descriptive relationship between age and each investigated pharmacokinetic parameter (peak concentration [C_max], time to C_max [t_max], area under the curve [AUC], clearance, volume of distribution, elimination-half-life) was derived using the final PBPK models, and verified with independent clinically observed data from 52 drugs.

RESULTS

The age-related changes in drug exposure were successfully simulated for all ten drugs. Pharmacokinetic parameters were predicted within 1.25-fold (70%), 1.5-fold (86%) and 2-fold (100%) of clinical data. AUC increased progressively by 0.9% per year throughout adulthood from the age of 20 years, which was explained by decreased clearance, while C_max, t_max and volume of distribution were not affected by human aging. Additional clinical data of 52 drugs were contained within the estimated variability of the established age-dependent correlations for each pharmacokinetic parameter.

CONCLUSION

The progressive decrease in hepatic and renal blood flow, as well as glomerular filtration, rate led to a reduced clearance driving exposure changes in the healthy elderly, independent of the drug.

Disproportionality Analysis of Safety Signals for a Wide Variety of Opioid-Related Adverse Events in Elderly Patients Using the Japanese Adverse Drug Event Report (JADER) Database

Opioids are widely used for the treatment of moderate/severe pain in cancer and noncancer patients. In this study, we searched for safety signals for a wide variety of opioid-related adverse events (AEs) in elderly patients by disproportionality analysis using the Japanese Adverse Drug Event Report (JADER) database. Data from the JADER database from April 2004 to May 2018 were obtained from the Pharmaceuticals and Medical Devices Agency website. Safety signal detection of opioid-related AEs in elderly patients was defined using the relative elderly reporting odds ratio (ROR). Among the analyzed AEs, opioid-induced neurotoxicity (OIN) was assessed based on the time to onset using the Weibull shape parameter. The following safety signals were detected in elderly patients: respiratory depression, somnolence, hallucinations, akathisia and OIN. Fentanyl, tramadol, oxycodone and morphine exhibited a large relative elderly ROR for OIN. The median time to onset of OIN of transdermal fentanyl, oral tramadol, oral oxycodone and oral morphine was 13.5, 6, 9, and 6 d, respectively. These opioids were classified as early failure types using the Weibull distribution. Our results showed that elderly patients who are administered opioids should be closely monitored for AEs, such as respiratory depression, OIN and akathisia.

Drug metabolism in severe chronic obstructive pulmonary disease: A phenotyping cocktail study

AIMS

To evaluate the effect of severe chronic obstructive pulmonary disease (COPD) on drug metabolism by comparing the pharmacokinetics of patients with severe COPD with healthy volunteers and using the modified Inje drug cocktail.

METHODS

This was a single-centre pharmacokinetic study with 12 healthy participants and 7 participants with GOLD D COPD. Midazolam 1 mg, dextromethorphan 30 mg, losartan 25 mg, omeprazole 20 mg, caffeine 130 mg and paracetamol 1000 mg were simultaneously administered and intensive pharmacokinetic sampling was conducted over 8 hours. Drug metabolism by CYP3A4, CYP2D6, CYP2C9, CYP2C19, CYP1A2, UGT1A6 and UGT1A9 in participants with COPD were compared with phenotypes in healthy controls.

RESULTS

The oral clearance (95% confidence interval) in participants with COPD relative to controls was: midazolam 63% (60-67%); dextromethorphan 72% (40-103%); losartan 53% (52-55%); omeprazole 35% (31-39%); caffeine 52% (50-53%); and paracetamol 73% (72-74%). There was a 5-fold increase in AUC for omeprazole and approximately 2-fold increases for caffeine, losartan, dextromethorphan, and midazolam. The AUC of paracetamol, which is mostly glucuronidated, was increased by about 60%.

CONCLUSION

Severe COPD is associated with a clinically significant reduction in oral drug clearance. This may be greater for cytochrome P450 substrates than for glucuronidated drugs. This supports reduced starting doses when prescribing for patients with severe COPD.

Intranasal midazolam for the sedation of geriatric patients with care-resistant behaviour during essential dental treatment: An observational study

OBJECTIVES

To describe the efficacy and safety of intranasal midazolam for sedation during essential dental treatment of geriatric patients with major neurocognitive disorder (MND) and care-resistant behaviour (CRB).

BACKGROUND

Dental treatment is often impossible in geriatric MND patients with CRB. Intranasal midazolam may provide a non-invasive sedation method, but there is currently no information on its use in geriatric patients.

METHODS

In this observational study, we included geriatric patients with severe MND and CRB needing urgent dental treatment. Each patient received 5 mg midazolam intranasally. Agitation/sedation levels, heart rate, respiration rate and oxygen saturation were recorded at 5-minute intervals.

RESULTS

Thirty two patients were included. Mean age was 84 (±7) years. Mean (SD) time to treatment start was 13 (±5) minutes, and mean time to maximum sedation 17 (±11) minutes. Sedation was sufficient to enable dental treatment to be completed in 31 (97%) patients. Anxiolysis/light sedation occurred in 16 (50%) patients, and moderate to deep sedation occurred in 16 (50%) patients. No patients suffered from apnoea, although 3 patients required a chin-lift manoeuvre. Hypoxaemia occurred in 1 of these patients and in 2 other patients without airway obstruction. All patients recovered uneventfully. In a regression model, age, weight and other sedative medication use were found not to be associated with maximum sedation depth.

CONCLUSIONS

Of 5 mg intranasal midazolam facilitates treatment of geriatric patients with MND in the comfort of their own environment. More information is needed to guide titration to balance the desired sedation level and patient safety.

Induction and maintenance of procedural sedation in adults: focus on remimazolam injection

Introduction: Procedural sedation (PS) is a humane way to help patients get through painful medical procedures by the administration of sedative drugs combined with analgesics. However, each of the currently used medications has certain shortcomings, urging the search for a new drug. Remimazolam, a novel benzodiazepine, is an ultra-short-acting hypnotic agent invented out of the 'soft drug' development.Areas covered: This presented review provides an overview of the drugs used in clinical practice for the induction and maintenance of procedural sedation in adults, focusing on the newly investigated benzodiazepine remimazolam. Literature search was conducted using the MEDLINE and ClinicalTrial.gov databases from January 2007 to December 2020.Expert opinion: Based on the reported clinical trials so far, remimazolam has demonstrated its effectiveness and safety with promising properties including rapid onset, short duration of action, predictable and consistent recovery profile, metabolism almost unaffected by liver or renal function, with non or minimal cardiorespiratory depression, and availability with a reversal drug. With marketing approval received recently, remimazolam is expected to have a place in the practice for procedural sedation in the near future if its efficacy and safety are further confirmed by more clinical trials and post-market analyses.

Midazolam Premedication Immediately Before Surgery Is Not Associated With Early Postoperative Delirium

BACKGROUND

Postoperative delirium is common among older surgical patients and may be associated with anesthetic management during the perioperative period. The aim of this study is to assess whether intravenous midazolam, a short-acting benzodiazepine used frequently as premedication, increased the incidence of postoperative delirium.

METHODS

Analyses of existing data were conducted using a database created from 3 prospective studies in patients aged 65 years or older who underwent elective major noncardiac surgery. Postoperative delirium occurring on the first postoperative day was measured using the confusion assessment method. We assessed the association between the use or nonuse of premedication with midazolam and postoperative delirium using a χ2 test, using propensity scores to match up with 3 midazolam patients for each control patient who did not receive midazolam.

RESULTS

A total of 1266 patients were included in this study. Intravenous midazolam was administered as premedication in 909 patients (72%), and 357 patients did not receive midazolam. Those who did and did not receive midazolam significantly differed in age, Charlson comorbidity scores, preoperative cognitive status, preoperative use of benzodiazepines, type of surgery, and year of surgery. Propensity score matching for these variables and American Society of Anesthesiology physical status scores resulted in propensity score-matched samples with 1-3 patients who used midazolam (N = 749) for each patient who did not receive midazolam (N = 357). After propensity score matching, all standardized differences in preoperative patient characteristics ranged from -0.07 to 0.06, indicating good balance on baseline variables between the 2 exposure groups. No association was found between premedication with midazolam and incident delirium on the morning of the first postoperative day in the matched dataset, with odds ratio (95% confidence interval) of 0.91 (0.65-1.29), P = .67.

CONCLUSIONS

Premedication using midazolam was not associated with higher incidence of delirium on the first postoperative day in older patients undergoing major noncardiac surgery.

Midazolam and hydroxymidazolam plasma concentrations can be monitored with selected biochemical and physiological parameters of palliative care patients

RATIONALE & OBJECTIVE

Midazolam is one of top three drugs used in palliative care. Its use increases in the last days of hospice patients' lives while safe dosage can be challenging. Equations currently used to estimate glomerular filtration rate, e.g: the Cockroft-Gault (eGFR_CR) and the Modification of Diet in Renal Disease (eGFR_MDRD) ones, do not generate precise calculations, especially in palliative patients exhibiting variations in body parameters. Our aim was to seek new relationships between mean midazolam (M_avg) and alfahydroxymidazolam (OH-M_avg) concentrations in plasma, and selected biochemical and physiological parameters of palliative patients, to enable optimal midazolam pharmacotherapy.

STUDY DESIGN, PARTICIPANTS AND INTERVENTIONS

The pilot study included 11 Caucasians, aged 42-95, with advanced cancer disease, receiving midazolam in a hospice in-patient unit. We tested correlations among M_avg, BMI, eGFR_MDRD, midazolam clearance (CL), OH-M_avg, bilirubin (Bil) and blood creatinine concentration (Cr). F test and leave-one out (LOO) validation was applied to verify the correlations' significance and predictive ability.

RESULTS

We found ten statistically significant (p < 0.05) correlations related to midazolam pharmacokinetics and physiological factors. We formulated two equations with high degree of predictive ability, based on the eGFR_MDRD→CL and the (Bil + BMI × Ln(Cr))→M_avg-(OH-M_avg) correlations. The limitations of the study mainly revolve around its pilot nature and the need to continue testing the results on a bigger population. No funding to disclose.

CONCLUSIONS

The significance of correlations corresponding to the arithmetic expressions confirms that Bil, BMI, Ln(Cr) analyzed simultaneously report a series of processes on which midazolam metabolism depends. Two of ten correlations proposed came close to meet all LOO validation criteria. Current findings can help optimize midazolam treatment in palliative therapy.

The Prevalence and Characteristics of Psychotropic-Related Hospitalizations in Older People: A Systematic Review and Meta-Analysis

OBJECTIVES

To assess the prevalence and characteristics of psychotropic medication-related hospitalizations in older people.

DESIGN

Systematic review with meta-analysis.

SETTING AND PARTICIPANTS

Older adults (≥65 years of age) with psychotropic-related hospitalizations.

METHODS

A search of published literature was performed in Medline, Embase, CINAHL, and Scopus from 2010 to March 2020. Three authors independently screened titles, abstracts, and full texts of relevant studies for relevance. Two authors independently extracted full text data, including characteristics, measures of causality, prevalence data, and performed quality assessment. A meta-analysis was conducted to estimate pooled prevalence and 95% confidence intervals (CIs) of psychotropic-related hospitalizations using random effects models. Heterogeneity was explored using subgroup analyses.

RESULTS

Of 815 potentially relevant studies, 11 were included in the final analysis. Five studies were cross-sectional studies, 5 were cohort studies, and 1 was a case control study. The majority of studies were rated as good quality. Psychotropic medications contributed to 2.1% (95% CI 1.2%-3.3%) of total hospitalizations and 11.3% (95% CI 8.2%-14.8%) of adverse drug event-related hospitalizations. The main psychotropic medications attributable to hospitalizations were antidepressants, hypnotics, sedatives, and antipsychotics.

CONCLUSIONS AND IMPLICATIONS

Psychotropic medications are a significant contributor to hospitalizations in older adults. The risk of hospitalization was greatest for those taking antidepressants, antipsychotics, hypnotics, and sedatives. Future studies should aim to address specific medication subgroups and implement uniform adverse drug event-related classification systems to improve comparability across studies.

Management of Ambulatory Anesthesia in Older Adults

The number of older patients is increasing globally. Combined with the growing number of ambulatory surgeries, many older patients will undergo ambulatory surgery in the future. The ambulatory setting offers many advantages: early mobilization, higher patient satisfaction, lower costs, and a low incidence of several complications such as infections and thromboembolic events. Moreover, cognitive recovery seems to be enhanced compared with in-hospital surgery, and both frail patients and patients with dementia can benefit from ambulatory surgery. This review provides suggestions for managing perioperative anesthesia for older patients in the ambulatory setting. Not all older patients are eligible for ambulatory surgery, and clinicians must be aware of risk factors for complications, especially frailty. Most anesthesia techniques and agents can be used in the ambulatory setting, but short-acting agents are preferred to ensure fast recovery. Both regional and general anesthesia are useful, but clinicians must be familiar with the physiological changes and specific implications in the older population. The older patients are more sensitive to anesthetic agents, meaning that a lower dose is needed to obtain the desired effect. However, they exhibit huge variation in pharmacodynamics and pharmacokinetics. Prolonged onset time may lead to overdosing and extended recovery. After surgery, effective pain management with opioid minimization is essential to ensure rapid recovery.

Pharmacokinetics and Pharmacodynamics of Remimazolam (CNS 7056) after Continuous Infusion in Healthy Male Volunteers: Part I. Pharmacokinetics and Clinical Pharmacodynamics

BACKGROUND

Remimazolam (CNS 7056) is a new ultra-short-acting benzodiazepine for intravenous sedation and anesthesia. Its pharmacokinetics and pharmacodynamics have been reported for bolus administration. This study aimed to investigate the pharmacokinetics and pharmacodynamics of remimazolam after continuous infusion.

METHODS

Twenty healthy male volunteers (20 to 38 yr, 64 to 99 kg) received remimazolam as continuous intravenous infusion of 5 mg/min for 5 min, 3 mg/min for the next 15 min, and 1 mg/min for further 15 min. Pharmacokinetics of remimazolam and its metabolite were determined from arterial plasma concentrations. Sedation was assessed using the Modified Observer's Assessment of Alertness and Sedation scale. Pharmacokinetic-pharmacodynamic modeling was performed by population analysis. Hemodynamics and the electrocardiogram were also investigated.

RESULTS

Pharmacokinetics was best described by a three-compartment model for remimazolam and a two-compartment model with transit compartment for the metabolite. Remimazolam showed a high clearance (1.15 ± 0.12 l/min, mean ± SD), a small steady-state volume of distribution (35.4 ± 4.2 l) and a short terminal half-life (70 ± 10 min). The simulated context-sensitive halftime after an infusion of 4 h was 6.8 ± 2.4 min. Loss of consciousness was observed 5 ± 1 min after start, and full alertness was regained 19 ± 7 min after stop of infusion. Pharmacodynamics of Modified Observer's Assessment of Alertness and Sedation score was best described by a sigmoid probability model with effect site compartment. The half-maximum effect site concentration for a Modified Observer's Assessment of Alertness and Sedation score less than or equal to 1 was 695 ± 239 ng/ml. The equilibration half-time between central and effect compartment was 2.7 ± 0.6 min. Mean arterial blood pressure decreased by 24 ± 6%, and heart rate increased by 28 ± 15%. Spontaneous breathing was maintained throughout the study. There was no significant prolongation of the QT interval of the electrocardiogram observed.

CONCLUSIONS

Remimazolam was characterized by a pharmacokinetic-pharmacodynamic profile with fast onset, fast recovery, and moderate hemodynamic side effects.

A pharmacokinetic-pharmacodynamic real-time display may change anesthesiologists' behavior

We have developed a real-time graphical display that presents anesthetic pharmacology data (drug effect site concentrations (Ce) and probability of anesthetic effects including hypnosis, loss of response to tracheal intubation), improving a previous prototype. We hypothesized that the use of the display alters (1) clinical behavior of anesthesiologists (i.e., Ce of isoflurane and fentanyl at the end of anesthesia), (2) fentanyl dose during the first 30 min of recovery in the post anesthesia care unit (PACU), and that the response of clinicians to the display in terms of workload and utility is favorable. The display was evaluated in a two-group, non-randomized prospective observational study of 30 patients undergoing general anesthesia using isoflurane and fentanyl. The isoflurane-predicted Ce was lower in the display group (without-display: 0.64% ± 0.06%; with-display: 0.42 ± 0.04%; t_23.9 = 3.17, P = 0.004 < adjusted alpha 0.05/2). The difference in fentanyl-predicted Ce did not achieve statistical significance (without-display: 1.5 ± 0.1 ng/ml; with-display: 2.0 ± 0.2 ng/ml; t_25.5 = 2.26, P = 0.03 > adjusted alpha 0.05/2) (means ± standard error). A joint test of isoflurane and fentanyl Ce with respect to the display condition rejected the null hypothesis of no differences (Hotelling T2, P = 0.01), supporting our primary hypothesis. The total fentanyl per patient during the first 30 min in the PACU with the display was 75.0 ± 62.7 µg and that without the display was 83.0 ± 74.7 µg. There was no significant difference between the groups (means ± standard deviation, P = 0.75). There were no differences in perceived workload. Use of the display does not appear to be cognitively burdensome and may change the anesthesiologist's dosing regimen.

Pharmacokinetics of midazolam and its major metabolite 1-hydroxymidazolam in the ball python (Python regius) after intracardiac and intramuscular administrations

Midazolam is a benzodiazepine with sedative, muscle relaxant, anxiolytic, and anticonvulsant effects. Twelve ball pythons (Python regius) were used in a parallel study evaluating the pharmacokinetics of 1 mg/kg midazolam following a single intracardiac (IC) or intramuscular (IM) administration. Blood was collected from a central venous catheter placed 7 days prior, or by cardiocentesis, at 15 time points starting just prior to and up to 72 hr after drug administration. Plasma concentrations of midazolam and 1-hydroxymidazolam were determined by the use of high-performance liquid chromatography tandem-mass spectrometry and pharmacokinetic parameters were estimated using noncompartmental analysis. The mean ± SD terminal half-lives of IC and IM midazolam were 12.04 ± 3.25 hr and 16.54 ± 7.10 hr, respectively. The area under the concentration-time curve extrapolated to infinity, clearance, and apparent volume of distribution in steady-state of IC midazolam were 19,112.3 ± 3,095.9 ng*hr/ml, 0.053 ± 0.008 L hr^-1  kg^-1 , and 0.865 ± 0.289 L/kg, respectively. The bioavailability of IM midazolam was estimated at 89%. Maximum plasma concentrations following an IM administration were reached 2.33 ± 0.98 hr and 24.00 ± 14.12 hr postinjection for midazolam and 1-hydroxymidazolam, respectively, and 22.33 ± 20.26 hr postinjection for 1-hydroxymidazolam following IC administration.

Pharmacologic and Nonpharmacologic Interventions for Perioperative Anxiety in Patients Undergoing Mohs Micrographic Surgery: A Systematic Review

BACKGROUND

Perioperative anxiety is associated with negative patient outcomes in Mohs micrographic surgery (MMS). Both pharmacologic and nonpharmacologic therapies have been used to alleviate perioperative anxiety in MMS.

OBJECTIVE

To systematically evaluate the efficacy of therapies aimed at reducing perioperative anxiety in MMS.

METHODS AND MATERIALS

Eligible articles were identified using PubMed MEDLINE, Cochrane Central Register of Controlled Trials, metaRegister of Controlled Trials, ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform. All available studies investigating interventions to reduce perioperative anxiety during MMS were considered.

RESULTS

Of the 183 abstracts identified and screened, 5 studies met inclusion criteria. Three studies reported a postintervention reduction in patient anxiety (midazolam, educational video, and personalized music). Two studies reporting on similar interventions did not find an effect.

CONCLUSION

There is currently limited evidence to support either pharmacologic or nonpharmacologic therapy for alleviation of perioperative patient anxiety in MMS. Midazolam may provide patients a short-term benefit, though any estimate of the effect is very uncertain. Personalized music may be a promising nonpharmacologic intervention for future research.

Prescribing issues in elderly individuals living with HIV

Introduction: Combined antiretroviral therapy has transformed HIV infection into a chronic disease thus people living with HIV (PLWH) live longer. As a result, the management of HIV infection is becoming more challenging as elderly experience age-related comorbidities leading to complex polypharmacy and a higher risk for drug-drug or drug-disease interactions. Furthermore, age-related physiological changes affect pharmacokinetics and pharmacodynamics thereby predisposing elderly PLWH to incorrect dosing or inappropriate prescribing and consequently to adverse drug reactions and the subsequent risk of starting a prescribing cascade. Areas covered: This review discusses the demographics of the aging HIV population, physiological changes and their impact on drug response as well as comorbidities. Particular emphasis is placed on common prescribing issues in elderly PLWH including drug-drug interactions with antiretroviral drugs. A PubMed search was used to compile relevant publications until February 2019. Expert opinion: Prescribing issues are highly prevalent in elderly PLWH thus highlighting the need for education on geriatric prescribing principles. Adverse health outcomes potentially associated with polypharmacy and inappropriate prescribing should promote interventions to prevent harm including medication reconciliation, medication review, and medication prioritization according to the risks/benefits for a given patient. A multidisciplinary team approach is recommended for the care of elderly PLWH.

Midazolam: Safety of use in palliative care: A systematic critical review

PURPOSE

The undesired effects of midazolam can be life-threatening. This paper delineates the findings related to the pharmacokinetics, adverse effects and drug-drug interactions as well as associated therapeutic implications for safe midazolam use.

METHODS

A systematic review of literature was conducted.

RESULTS

The pharmacokinetics of midazolam depends on hepatic and renal functions, fat tissue mass, route and duration of administration, as well as potential drug-drug interactions. Palliative care patients constitute a high-risk group prone to side effects of drugs, due to polytherapy and multi-organ failure.

CONCLUSION

Midazolam is one of three most frequently administered drugs in palliative care. The indications for its use include anxiety, dyspnea, seizures, vomiting refractory to treatment, agitation, myoclonus, status epilepticus, restlessness, delirium, pruritus, hiccups, insomnia, analgosedation, palliative sedation and preventing or counteracting undesired effects of ketamine.

Clinical and demographic characteristics of geriatric patients with acute poisoning in the state of Uttarakhand

Background:

Acute poisoning in geriatric age group is a clinical challenge due to multiple comorbidities and complications in this age group. There are very few studies done in the past, which have addressed this issue.

Materials and Methods:

This retrospective observational study was a carried out in the Department of Emergency Medicine of a tertiary care hospital of Uttarakhand over a period of 1 year from November 2017 to October 2018. Detailed demographic data and clinical history of patients with alleged history of acute poisoning was obtained from the hospital record section.

Results:

During the period of 1 year, 156 patients of acute poisoning attended the medical emergency department, of which 53 (33.9%) patients belonged to geriatric age group (>60 years). Maximum number of patients belonged to the age group of 71–80 years (n = 26, 16.6%). Males outnumbered female patients. The most common toxidrome in geriatric age group was alcohol intoxication followed by pesticide (organophosphorus) poisoning. Unintentional exposure of toxin in the form of drug over dosage encompassed more than one-third of poisonings in geriatric population. Nine (16.9%) geriatric patients succumbed to poisoning. Complications such as acute renal failure, shock, respiratory distress, acute liver injury, and need for ventilator support were more common in nonsurvivors as compared with survivors.

Conclusion:

The study demonstrated mortality of 16.9% (n = 9) among geriatric patients with alleged history of acute poisoning. The risk factors attributing to mortality were shock, aspiration pneumonia, and acute liver injury. Although cases of suicidal exposure outnumbered cases of unintentional exposure, the latter group comprised of a considerable number. Clearly, more attention is needed while managing a case of acute poisoning of geriatric age group as their pattern of presentation and complications differ from that of younger age group.

HIV and Aging - Perhaps Not as Dramatic as We Feared?

Ever since the introduction of highly active antiretroviral therapy (ART) in 1995, HIV infection has been linked to "metabolic" complications (insulin resistance, dyslipidemia, osteoporosis, and others). Studies suggested increased rates of myocardial infarction, renal insufficiency, neurocognitive dysfunction, and fractures in HIV-postitive patients. Even long-term suppression of HIV seemed to be accompanied by an excess of deleterious inflammation that could promote these complications. The aims of this viewpoint paper are to summarize recent data and to examine the possibility that the problem of aging-related morbidity in HIV might not be as dramatic as previously believed.

Efficacy of two types of palliative sedation therapy defined using intervention protocols: proportional vs. deep sedation

PURPOSE

This study investigated the effect of two types of palliative sedation defined using intervention protocols: proportional and deep sedation.

METHODS

We retrospectively analyzed prospectively recorded data of consecutive cancer patients who received the continuous infusion of midazolam in a palliative care unit. Attending physicians chose the sedation protocol based on each patient's wish, symptom severity, prognosis, and refractoriness of suffering. The primary endpoint was a treatment goal achievement at 4 h: in proportional sedation, the achievement of symptom relief (Support Team Assessment Schedule (STAS) ≤ 1) and absence of agitation (modified Richmond Agitation-Sedation Scale (RASS) ≤ 0) and in deep sedation, the achievement of deep sedation (RASS ≤ - 4). Secondary endpoints included mean scores of STAS and RASS, deep sedation as a result, and adverse events.

RESULTS

Among 398 patients who died during the period, 32 received proportional and 18 received deep sedation. The treatment goal achievement rate was 68.8% (22/32, 95% confidence interval 52.7-84.9) in the proportional sedation group vs. 83.3% (15/18, 66.1-100) in the deep sedation group. STAS decreased from 3.8 to 0.8 with proportional sedation at 4 h vs. 3.7 to 0.3 with deep sedation; RASS decreased from + 1.2 to - 1.7 vs. + 1.4 to - 3.7, respectively. Deep sedation was needed as a result in 31.3% (10/32) of the proportional sedation group. No fatal events that were considered as probably or definitely related to the intervention occurred.

CONCLUSION

The two types of intervention protocol well reflected the treatment intention and expected outcomes. Further, large-scale cohort studies are promising.

Pharmacokinetics, pharmacodynamics, and tolerability of USL261, midazolam nasal spray: Randomized study in healthy geriatric and non-geriatric adults

AIM

Characterize pharmacokinetics, pharmacodynamics, and safety/tolerability of USL261 in geriatric adults to inform its potential for treating bouts of increased seizure activity.

METHODS

Phase 1, randomized, double-blind, 2-way crossover study in healthy geriatric (≥65years; n=18) and non-geriatric (18-40years; n=12) adults evaluated single USL261 doses (2.5 and 5.0mg) administered intranasally. Pharmacokinetic parameters were estimated for midazolam and 1-hydroxymidazolam (active metabolite), including area under the plasma concentration-time curve (AUC), maximum plasma concentration (C_max), time to C_max (T_max), and half-life (t_1/2). Stanford Sleepiness Scale and Observer's Assessment of Alertness/Sedation assessed sedation; Digit-Symbol Substitution Test assessed psychomotor performance.

RESULTS

Midazolam exposure and plasma concentrations were higher in geriatric versus non-geriatric adults (geometric mean AUC_0-∞ [ng*h/mL] 2.5mg: 70 vs 54, respectively; 5.0mg: 157 vs 110; C_max [ng/mL] 2.5mg: 27.1 vs 22.5; 5.0mg: 55.8 vs 46.1). USL261 was rapidly absorbed, with no differences in median T_max (14.5-17.3min); mean t_1/2 was longer in geriatric subjects. Similar age-related trends were observed for 1-hydroxymidazolam. Mean maximum observed pharmacodynamic effects were not significantly different between age groups, though were more pronounced following 5.0 versus 2.5mg (P<.05); return to baseline was generally achieved within 4h. USL261 was generally well tolerated, with similar adverse event rates between age groups.

CONCLUSIONS

Despite increased midazolam exposure in geriatric subjects, there were no differences between age groups in pharmacodynamic effects or adverse event rates. USL261 was rapidly absorbed and pharmacodynamic effects returned to baseline within ~4h, regardless of age. Dose-dependent pharmacokinetic and maximum pharmacodynamic effects were observed. Overall, pharmacokinetic findings for USL261 were similar to studies evaluating intravenous midazolam, whereas pharmacodynamic effects were less pronounced in the elderly than previously reported.

Scaling clearance in paediatric pharmacokinetics: All models are wrong, which are useful?

Linked Articles

This article is commented on in the editorial by Holford NHG and Anderson BJ. Why standards are useful for predicting doses. Br J Clin Pharmacol 2017; 83: 685–7. doi: 10.1111/bcp.13230

Aim

When different models for weight and age are used in paediatric pharmacokinetic studies it is difficult to compare parameters between studies or perform model‐based meta‐analyses. This study aimed to compare published models with the proposed standard model (allometric weight^0.75 and sigmoidal maturation function).

Methods

A systematic literature search was undertaken to identify published clearance (CL) reports for gentamicin and midazolam and all published models for scaling clearance in children. Each model was fitted to the CL values for gentamicin and midazolam, and the results compared with the standard model (allometric weight exponent of 0.75, along with a sigmoidal maturation function estimating the time in weeks of postmenstrual age to reach half the mature value and a shape parameter). For comparison, we also looked at allometric size models with no age effect, the influence of estimating the allometric exponent in the standard model and, for gentamicin, using a fixed allometric exponent of 0.632 as per a study on glomerular filtration rate maturation. Akaike information criteria (AIC) and visual predictive checks were used for evaluation.

Results

No model gave an improved AIC in all age groups, but one model for gentamicin and three models for midazolam gave slightly improved global AIC fits albeit using more parameters: AIC drop (number of parameters), –4.1 (5), –9.2 (4), –10.8 (5) and –10.1 (5), respectively. The 95% confidence interval of estimated CL for all top performing models overlapped.

Conclusion

No evidence to reject the standard model was found; given the benefits of standardised parameterisation, its use should therefore be recommended.

Changes in Pharmacokinetics and Pharmacodynamics in the Elderly Patient

The use of pharmacologic agents in elderly patients is one of the most difficult aspects of patient care. An understanding of the common physiologic changes expected with aging is helpful to anticipate changes expected in pharmacokinetic parameters. Distribution, metabolism, and excretion are significantly altered for many drugs. In addition, pharmacodynamic variations in elderly patients may increase or decrease sensitivity to a medication independent of pharmacokinetic changes. These alterations are particularly noteworthy with cardiovascular and central nervous system agents. Current controversies regarding the application of estimation of renal function to drug dosing and use of the Beers criteria of medications potentially inappropriate in the elderly are discussed.

Evaluating a physiologically based pharmacokinetic model for predicting the pharmacokinetics of midazolam in Chinese after oral administration

AIM

To evaluate the SimCYP simulator ethnicity-specific population model for predicting the pharmacokinetics of midazolam, a typical CYP3A4/5 substrate, in Chinese after oral administration.

METHODS

The physiologically based pharmacokinetic (PBPK) model for midazolam was developed using a SimCYP population-based simulator incorporating Chinese population demographic, physiological and enzyme data. A clinical trial was conducted in 40 Chinese subjects (the half was females) receiving a single oral dose of 15 mg midazolam. The subjects were separated into 4 groups based on age (20-50, 51-65, 66-75, and above 76 years), and the pharmacokinetics profiles of each age- and gender-group were determined, and the results were used to verify the PBPK model.

RESULTS

Following oral administration, the simulated profiles of midazolam plasma concentrations over time in virtual Chinese were in good agreement with the observed profiles, as were AUC and Cmax. Moreover, for subjects of varying ages (20-80 years), the ratios of predicted to observed clearances were between 0.86 and 1.12.

CONCLUSION

The SimCYP PBPK model accurately predicted the pharmacokinetics of midazolam in Chinese from youth to old age. This study may provide novel insight into the prediction of CYP3A4/5-mediated pharmacokinetics in the Chinese population relative to Caucasians and other ethnic groups, which can support the rational design of bridging clinical trials.

Pharmacotherapy in the ageing patient: The impact of age per se (A review)

A literature search was carried out to review the influence of 'ageing' on pharmacotherapeutic decision-making, specifically how 'age' is defined and considered in the utilisation of medication. Embase, Medline, International Pharmaceutical Abstracts, and Google scholar were canvassed in a three-tiered search according to pre-established inclusion criteria. In tier 1, a total of 22 studies were identified highlighting the underutilisation of medication in elderly patients, with a particular focus on warfarin. Four studies highlighted an age-bias in medication-prescribing for elderly patients, specifically in relation to medicines for rheumatoid arthritis, angina, and hypertension. Tier 2 identified diverse definitions for 'elderly', including biological age, chronological age, physiological age, as well as various descriptions of 'elderly' in clinical trials and guidelines. Finally, medication optimisation tools were identified through the third tier, emphasising the use of chronological age to describe the 'elderly'. Old age influences pharmacotherapeutic decision-making at various levels, however, what complicates the situation is the absence of a comprehensive definition of 'elderly'. Clinical recommendations need to be based more on objective factors known to affect medication effectiveness and safety.

Association between use of benzodiazepines and risk of fractures: a meta-analysis

Benzodiazepines (BZDs) are some of the most commonly prescribed drugs in the world. It has been shown that BZD use could be associated with increased fracture risk. However, studies on the use of BZDs and fracture risk have yielded inconsistent results. Results from the present meta-analysis show that BZD use is associated with a moderate and clinically significant increase in the risk of fractures.

INTRODUCTION

The relationship between the use of BZDs and fracture risk has been neither well identified nor summarized. This meta-analysis reports on the use of BZDs, especially short-acting BZDs, and their correlation with a moderate and clinically significant increase in fracture risk. This analysis will provide evidence for clinicians to consider fracture risk when prescribing BZDs among the elderly population. This study was conducted to determine whether people who take BZDs are at an increased fracture risk.

METHODS

A systematic search of studies published through January 2013 was conducted using MEDLINE, EMBASE, OVID, and ScienceDirect. Case-control and cohort studies that assessed the relationship between BZD use and the risk of fractures were identified. Literature searches, study selections, methodological assessments, and data mining were independently conducted by two reviewers. Disagreements were resolved by consensus. STATA 12.0 software was used for the meta-analysis. Random effects models were used for pooled analysis due to heterogeneity among the studies.

RESULTS

There were 25 studies, including 19 case-control studies and 6 cohort studies, that met the inclusion criteria. Overall, the results of the meta-analysis indicated that BZD use was associated with a significantly increased fracture risk (relative risk (RR) = 1.25; 95% confidence intervals (CI), 1.17-1.34; p < 0.001). Increased fracture risk associated with BZD use was observed in participants aged ≥65 years old (RR = 1.26; 95% CI, 1.15-1.38; p < 0.001). When only hip fractures were included as the outcome measure, the RR increased to 1.35. However, subgroup meta-analyses showed that there was no significant association between BZD use and fracture risk in Eastern countries (RR = 1.27; 95% CI, 0.76-2.14; p = 0.362) as well as between long-acting BZD use and risk of fractures (RR = 1.21; 95% CI, 0.95-1.54; p = 0.12). After accounting for publication bias, we observed that the overall association between BZD use and fracture risk to be slightly weaker (RR = 1.21; 95% CI, 1.13-1.30) but still significant.

CONCLUSION

The results of this meta-analysis demonstrate that the use of BZD, especially short-acting BZD, is associated with a moderate and clinically significant increase in fracture risk. However, large prospective studies that minimize selection bias are necessary to determine a more accurate fracture risk associated with BZD use.

Assessing circadian rhythms during prolonged midazolam infusion in the pediatric intensive care unit (PICU) children

BACKGROUND

This study evaluates possible circadian rhythms during prolonged midazolam infusion in 27 pediatric intensive care unit (PICU) children under mechanical ventilation.

METHODS

Blood samples for midazolam and 1-OH-midazolam assay were collected throughout the infusion at different times of the day. The blood pressure, heart rate and body temperature were recorded every hour for the rhythms analysis. Population nonlinear mixed-effect modeling with NONMEM was used for data analysis.

RESULTS

A two-compartment model for midazolam pharmacokinetics and a one-compartment model for midazolam metabolite adequately described the data. The 24 h profiles of all monitored physiological parameters were greatly disturbed/abolished in comparison with the well-known 24 h rhythmic patterns in healthy subjects. There was no significant circadian rhythm detected with respect to midazolam pharmacokinetics, its active metabolite pharmacokinetics and all monitored parameters.

CONCLUSIONS

We concluded that the light-dark cycle did not influence midazolam pharmacokinetics in intensive care units children. Also, endogenous rhythms in critically ill and sedated children are severely disturbed and desynchronized. Our results confirmed that it is necessary to adjust the dose of midazolam to the patient's body weight. The low value of midazolam clearances observed in our study was probably caused by mechanical ventilation, which was shown to decrease the cardiac output.

Why Candida sepsis should matter to ICU physicians

The incidence of candidemia and invasive Candida infections has increased substantially over the last 2 decades. These infections are associated with risk factors that characterize intensive care unit patients. Candidemia and invasive Candida are highly morbid and associated with significantly increased mortality. Outcomes in the intensive care setting depend on physician awareness and rapid intervention. The epidemiology of the disease, its diagnostic challenges, and management strategies, including prophylactic, preemptive, and definitive therapeutic approaches, are presented herein.

[Dexmedetomidine. Pharmacokinetics and pharmacodynamics]

Dexmedetomidine is a highly selective, potent α₂-adrenoceptor agonist which was approved in 2011 by the European Medicines Agency for sedation of patients in intensive care units (ICU). Dexmedetomidine exhibits sedative as well as analgesic and anxiolytic effects. Recent studies suggest that dexmedetomidine may be an alternative to midazolam in long-term ICU sedation. This review summarizes the pharmacokinetics and pharmacodynamics of dexmedetomidine particularly in ICU patients and with special regard to covariate effects. Although dexmedetomidine is currently approved only for use in adults the pharmacokinetics and pharmacodynamics in children will also be addressed as there are numerous studies on this off-label use.

Clinical pharmacology in old persons

The epidemiological transition, with a rapid increase in the proportion in the global population aged over 65 years from 11% in 2010 to 22% in 2050 and 32% in 2100, represents a challenge for public health. More and more old persons have multimorbidities and are treated with a large number of medicines. In advanced age, the pharmacokinetics and pharmacodynamics of many drugs are altered. In addition, pharmacotherapy may be complicated by difficulties with obtaining drugs or adherence and persistence with drug regimens. Safe and effective pharmacotherapy remains one of the greatest challenges in geriatric medicine. In this paper, the main principles of geriatric pharmacology are presented.

The effect of age on the discriminative stimulus effects of ethanol and its GABA(A) receptor mediation in cynomolgus monkeys

RATIONALE

Excessive alcohol consumption is less common among aged compared to young adults, with aged adults showing greater sensitivity to many behavioral effects of ethanol.

OBJECTIVES

This study compared the discriminative stimulus effects of ethanol in young and middle-aged adult cynomolgus monkeys (Macaca fascicularis) and its γ-aminobutyric acid (GABA)(A) receptor mediation.

METHODS

Two male and two female monkeys trained to discriminate ethanol (1.0 g/kg, i.g.; 60-min pre-treatment interval) from water at 5-6 years of age (Grant et al. in Psychopharmacology 152:181-188, 2000) were re-trained in the current study more than a decade later (19.3 ± 1.0 years of age) for a within-subjects comparison. Also, four experimentally naïve middle-aged (mean ± SEM, 17.0 ± 1.5 years of age) female monkeys were trained to discriminate ethanol for between-subjects comparison with published data from young adult naïve monkeys.

RESULTS

Two of the naïve middle-aged monkeys attained criterion performance, with weak stimulus control and few discrimination tests, despite greater blood-ethanol concentration 60 min after 1.0 g/kg ethanol in middle-aged compared to young adult female monkeys (Green et al. in Alcohol Clin Exp Res 23:611-616, 1999). The efficacy of the GABA(A) receptor positive modulators pentobarbital, midazolam, allopregnanolone, pregnanolone, and androsterone to substitute for the discriminative stimulus effects of 1.0 g/kg ethanol was maintained from young adulthood to middle age.

CONCLUSIONS

The data suggest that 1.0 g/kg ethanol is a weak discriminative stimulus in naive middle-aged monkeys. Nevertheless, the GABA(A) receptor mechanisms mediating the discriminative stimulus effects of ethanol, when learned as a young adult, appear stable across one third of the primate lifespan.

A maturation model for midazolam clearance

BACKGROUND

Physiological-based pharmacokinetic models have been used to describe midazolam clearance (CL) maturation. There are no maturation descriptors of CL from neonate to adulthood based on reported estimates at different ages.

METHODS

Published CL estimates after intravenous administration from time-concentration profiles were used to construct a maturation model based on size and age. Curve fitting was performed using nonlinear mixed effects models.

RESULTS

There were 16 publications reporting an estimate of CL after intravenous administration in children, although few estimates were available from 44-80 weeks postmenstrual age (PMA). CL maturation, standardized to a 70 -kg person was described using the Hill equation. Mature CL was 523 (CV 32%, 95%CI 469, 597) ml·min(-1) ·70 kg(-1) . The maturation half-time was 73.6 (95%CI 59.4, 80.0) weeks PMA and the Hill coefficient 3 (95%CI 2.2, 4.1). Predicted CL changes with age based on this model were in close agreement with physiologically based pharmacokinetic (PBPK) models. A comparison with a published PBPK model predictions revealed a root mean squared prediction error (precision) of 4.0% (95%CI 1.1, 5.8) and bias was -0.9% (95%CI -4.3, 2.6).

CONCLUSIONS

Previously published pharmacokinetic parameters can be used to develop maturation models that address gaps in current knowledge regarding the influence of age on a drug's disposition. If a midazolam sedation target concentration of 0.1 mg·l(-1) , similar to that given to adults, is assumed, then we might anticipate steady-state infusion rates of 0.014 mg·kg(-1) ·h(-1) in neonates, 0.05 mg·kg(-1) ·h(-1) in a 1-year-old, 0.06 mg·kg(-1) ·h(-1) in a 5-year-old and 0.05 mg·kg(-1) ·h(-1) in a 12-year-old child. Age-related pharmacodynamic differences that will affect dose and the impact of active metabolites on response are not yet quantified.

Pharmacokinetic and pharmacodynamic properties of cholinesterase inhibitors donepezil, tacrine, and galantamine in aged and young Lister hooded rats

Physiological alterations that may change pharmacological response accompany aging. Pharmacokinetic/pharmacodynamic properties of cholinesterase inhibitors (ChEIs) used in the treatment of Alzheimer's disease, donepezil, tacrine, and galantamine, were investigated in an aged Lister hooded rat model. Intravenous and oral 6-h blood sampling profiles in old (30 months old) and young (7 months old) rats revealed pharmacokinetic changes similar to those in humans with an approximately 40% increase in C(max) of galantamine and prolonged t(1/2) (1.4-fold) and mean residence time (1.5-fold) of donepezil. Tacrine disposition was maintained with age, and area under the concentration-time curve and clearance in old rats were similar to those in young rats for all drugs tested as was bioavailability. Old rats showed a trend of increased pharmacodynamic sensitivity (<20%) to ChEIs in cholinesterase activity assays, which was attributed to pharmacokinetic effects because a trend of higher blood and brain concentrations was seen in the old rats although brain/blood ratios remained unaffected. Enhanced cholinergic-mediated behaviors such as tremor, hypothermia, salivation, and lacrimation were also observed in the old rats, which could not be accounted for by a similar magnitude of change in pharmacokinetics. A decrease in expression of muscarinic acetylcholine receptor subtype 2 detected in old rat brains was postulated to play a role. Greater age effects in both pharmacokinetics and pharmacodynamics of donepezil and tacrine were seen in previous studies with Fischer 344 rats, indicating a potential risk in overreliance on this rat strain for aging studies.

Enhancement of GABAergic activity: neuropharmacological effects of benzodiazepines and therapeutic use in anesthesiology

GABA is the major inhibitory neurotransmitter in the central nervous system (CNS). The type A GABA receptor (GABA(A)R) system is the primary pharmacological target for many drugs used in clinical anesthesia. The α1, β2, and γ2 subunit-containing GABA(A)Rs located in the various parts of CNS are thought to be involved in versatile effects caused by inhaled anesthetics and classic benzodiazepines (BZD), both of which are widely used in clinical anesthesiology. During the past decade, the emergence of tonic inhibitory conductance in extrasynaptic GABA(A)Rs has coincided with evidence showing that these receptors are highly sensitive to the sedatives and hypnotics used in anesthesia. Anesthetic enhancement of tonic GABAergic inhibition seems to be preferentially increased in regions shown to be important in controlling memory, awareness, and sleep. This review focuses on the physiology of the GABA(A)Rs and the pharmacological properties of clinically used BZDs. Although classic BZDs are widely used in anesthesiological practice, there is a constant need for new drugs with more favorable pharmacokinetic and pharmacodynamic effects and fewer side effects. New hypnotics are currently developed, and promising results for one of these, the GABA(A)R agonist remimazolam, have recently been published.