Tamoxifen pharmacokinetics and pharmacodynamics in older patients with non-metastatic breast cancer.

BACKGROUND: We aimed to study the pharmacokinetics and -dynamics of tamoxifen in older women with non-metastatic breast cancer. METHODS: Data for this analysis were derived from the CYPTAM study (NTR1509) database. Patients were stratified by age (age groups < 65 and 65 and older). Steady-state trough concentrations were measured of tamoxifen, N-desmethyltamoxifen, 4-hydroxy-tamoxifen, and endoxifen. CYP2D6 and CYP3A4 phenotypes were assessed for all patients by genotyping. Multiple linear regression models were used to analyze tamoxifen and endoxifen variability. Outcome data included recurrence-free survival at time of tamoxifen discontinuation (RFSt) and overall survival (OS). RESULTS: 668 patients were included, 141 (21%) were 65 and older. Demographics and treatment duration were similar across age groups. Older patients had significantly higher concentrations of tamoxifen 129.4 ng/ml (SD 53.7) versus 112.2 ng/ml (SD 42.0) and endoxifen 12.1 ng/ml (SD 6.6) versus 10.7 ng/ml (SD 5.7, p all < 0.05), independently of CYP2D6 and CYP3A4 gene polymorphisms. Age independently explained 5% of the variability of tamoxifen (b = 0.95, p < 0.001, R2 = 0.051) and 0.1% of the variability in endoxifen concentrations (b = 0.45, p = 0.12, R2 = 0.007). Older patients had worse RFSt (5.8 versus 7.3 years, p = 0.01) and worse OS (7.8 years versus 8.7 years, p = 0.01). This was not related to differences in endoxifen concentration (HR 1.0, 95% CI 0.96-1.04, p = 0.84) or CYP polymorphisms. CONCLUSION: Serum concentrations of tamoxifen and its demethylated metabolites are higher in older patients, independent of CYP2D6 or CYP3A4 gene polymorphisms. A higher bioavailability of tamoxifen in older patients may explain the observed differences. However, clinical relevance of these findings is limited and should not lead to a different tamoxifen dose in older patients.

The effect of combining therapeutic drug monitoring of antihypertensive drugs with personalised feedback on adherence and resistant hypertension: the (RHYME-RCT) trial protocol of a multi-centre randomised controlled trial.

BACKGROUND: Adherence to antihypertensive drugs (AHDs) is important for adequate blood pressure control. Not taking these drugs as prescribed is one of the main underlying causes for resistant hypertension (RH), which in turn leads to an increased risk of cardiovascular events, stroke and kidney damage. Therefore, correct identification of patients that are non-adherent to AHDs is crucial to improve clinical outcome. For this goal, therapeutic drug monitoring is the most reliable method. The primary objective of this trial is to investigate whether monitoring of drug concentrations with a dried blood spot (DBS) sampling method combined with personalised feedback leads to a decrease in prevalence of RH after 12 months due to an increase in adherence. Secondary objectives include the difference over time in the number of required AHDs as well as the defined daily dose (DDD). Lastly, the cost-utility of SoC versus the intervention in RH is determined. METHODS: This is a multi-centre single-blinded randomised controlled trial (RHYME-RCT). First, at an eligibility visit, DBS sampling, to monitor drug concentrations in blood, and a 24-h ambulatory blood pressure measurement (24-h ABPM) are performed simultaneously. Patients with a daytime systolic blood pressure (SBP) > 135 and/or diastolic blood pressure (DBP) > 85 mmHg are randomised to SoC or intervention + SoC. The intervention is performed by the treating physician and includes information on drug concentrations and a comprehensive personalised feedback conversation with the use of a communication tool. The follow-up period is one year with visits at 3, 6 and 12 months randomisation and includes 24-h ABPM and DBS sampling. DISCUSSION: This will be the first trial that focusses specifically on patients with RH without taking into account suspicion of non-adherence and it combines monitoring of AHD concentrations to identify non-adherence to AHDs with a comprehensive feedback to improve non-adherence. Furthermore, if this trial shows positive outcomes for the intervention it can be directly implemented in clinical practice, which would be a great improvement in the treatment of RH. TRIAL REGISTRATION: RHYME-RCT is registered in the Dutch Trial Register on 27/12/2017 (NTR6914) and can be found in the International Clinical Trials Registry Platform.

Lessons learned from conducting a randomized controlled trial to improve non-adherence to antihypertensive drug treatment.

PURPOSE: Hypertension significantly contributes to cardiovascular diseases and premature deaths. Effective treatment is crucial to reduce cardiovascular risks, but poor adherence to antihypertensive drugs is a major issue. Numerous studies attempted to investigate interventions for identifying non-adherence, but often failed to address the issue effectively. The RHYME-RCT trial sought to bridge this gap by measuring non-adherence by determining antihypertensive drug concentrations in blood through a dried blood spot (DBS) method in patients with resistant hypertension. This measurement was followed by personalized feedback to improve adherence. During the course of this trial several challenges emerged, including selection bias, the gatekeeper role of physicians, the Hawthorne effect and the role of randomization. AIM: This communication aims to inform fellow researchers and clinicians of challenges that can arise when conducting clinical trials to improve adherence and offer insights for refining study designs to avoid these issues in forthcoming adherence studies.

Purpose: High blood pressure is a serious problem that can lead to heart and kidney problems and early deaths. Treating high blood pressure is therefore crucial. Initially, lifestyle changes are recommended, but if they don't work, medications are needed. However, taking these drugs daily can be challenging, and many patients miss doses which is called non-adherence. Despite numerous studies, a perfect solution hasn't been found to solve non-adherence to blood pressure lowering drugs.In the RHYME-RCT study, researchers aimed to improve drug adherence in patients with resistant hypertension. They monitored drug intake by measuring drug concentrations in the blood alongside 24-hour blood pressure monitoring. These data allowed healthcare providers to offer personalized advice to patients. The study encountered some important challenges in its design, including selection bias, where some participants shouldn't have been included or excluded in the study, and the Hawthorne effect, where patients changed their behavior because they knew they were being observed.Aim: This message is to inform fellow scientists and doctors about issues that can arise when conducting clinical trials to improve adherence and to encourage the exchange of ideas between scientists to improve future studies on medication adherence, which is essential for managing conditions like high blood pressure.

Abdominal aortic diameter and cardiovascular status in patients with idiopathic retroperitoneal fibrosis.

Although much debated, an exaggerated inflammatory response to advanced atherosclerosis has been implicated in the pathogenesis of idiopathic retroperitoneal fibrosis (RPF). Clinical presentation, infrarenal abdominal aortic diameter and RPF mass thickness were retrospectively analyzed in 166 patients with idiopathic RPF seen at our referral center between April 1998 and December 2019. Patients were stratified to their infrarenal abdominal aortic diameter at presentation (i.e., non-ectatic [< 25 mm]; ectatic [25-29 mm]; and aneurysmal [≥ 30 mm]) to compare characteristics across groups with an undilated or dilated aorta. Ectatic or aneurysmal aortic dilatation was present in 34% of patients. Most clinical characteristics did not differ across abdominal aortic diameter stratified groups, but RPF mass thickness was greater in patients presenting with aortic aneurysmal dilatation compared to that in patients with an undilated aorta (49.0 mm [IQR 34.0-62.0] vs 32.5 mm [IQR 25.3-47.8]; P < 0.001). A positive linear association was found between aortic diameter on a continuous scale and RPF mass thickness (ß 0.32 [95% CI 0.34-0.96]; P < 0.001). This association remained significant after adjusting for age, sex and acute-phase reactant levels (ß 0.28 [95% CI 0.15-0.95]; P < 0.01). Treatment success across aortic diameter stratified groups did not differ (P = 0.98). Treatment induced RPF mass regression was not associated with an increase in aortic expansion rate (P = 0.44). Aortic dilatation was prevalent among patients. Infrarenal abdominal aortic diameter was independently associated with RPF mass thickness. Findings support the concept that at least in a subset of patients, RPF may be secondary to advanced atherosclerosis.

[Improving the safety of antipsychotic drugs in children and adolescents by antipsychotic drug concentration measurements using a fingerprick]. / Naar veiliger antipsychoticagebruik bij jongeren: bloedspiegelbepalingen met vingerprik.

BACKGROUND: Antipsychotic drugs are associated with serious side effects in children and adolescents including weight gain. It is still unknown whether therapeutic drug monitoring (TDM) can improve patient outcomes. AIM: To test whether the dried blood spot method is a valid and feasible method to measure antipsychotic drug concentrations with a fingerprick; to assess the relationship between antipsychotic drug concentrations, side-effects and effectiveness in minors. METHOD: A dried blood spot (DBS) method was developed and tested for validity and feasibility. 89 children and adolescents with autism spectrum disorder (ASD) and behavioral problems were included in the multicenter, prospective, observational study SPACe (NTR6050). Antipsychotic drug concentrations, side-effects and effectiveness were measured during a 6-month follow-up. RESULTS: The DBS method showed a higher variability than venipuncture in measuring antipsychotic drug concentrations, but seemed feasible in minors with behavioral problems. Higher risperidon trough concentrations were associated with more weight gain and more effectiveness. A therapeutic window with optimal effectiveness and minimal side-effects was defined. CONCLUSION: The DBS method can be used to measure antipsychotic drug concentrations in children and adolescents with ASD and behavioral problems. As a relationship between antipsychotic drug concentrations and clinical outcomes was established, TDM might improve safety and effectiveness of antipsychotic drugs in this population.

The effect of therapeutic drug monitoring of beta-lactam and fluoroquinolones on clinical outcome in critically ill patients: the DOLPHIN trial protocol of a multi-centre randomised controlled trial.

BACKGROUND: Critically ill patients undergo extensive physiological alterations that will have impact on antibiotic pharmacokinetics. Up to 60% of intensive care unit (ICU) patients meet the pharmacodynamic targets of beta-lactam antibiotics, with only 30% in fluoroquinolones. Not reaching these targets might increase the chance of therapeutic failure, resulting in increased mortality and morbidity, and antibiotic resistance. The DOLPHIN trial was designed to demonstrate the added value of therapeutic drug monitoring (TDM) of beta-lactam and fluoroquinolones in critically ill patients in the ICU. METHODS: A multi-centre, randomised controlled trial (RCT) was designed to assess the efficacy and cost-effectiveness of model-based TDM of beta-lactam and fluoroquinolones. Four hundred fifty patients will be included within 24 months after start of inclusion. Eligible patients will be randomly allocated to either study group: the intervention group (active TDM) or the control group (non-TDM). In the intervention group dose adjustment of the study antibiotics (cefotaxime, ceftazidime, ceftriaxone, cefuroxime, amoxicillin, amoxicillin with clavulanic acid, flucloxacillin, piperacillin with tazobactam, meropenem, and ciprofloxacin) on day 1, 3, and 5 is performed based upon TDM with a Bayesian model. The primary outcome will be ICU length of stay. Other outcomes amongst all survival, disease severity, safety, quality of life after ICU discharge, and cost effectiveness will be included. DISCUSSION: No trial has investigated the effect of early TDM of beta-lactam and fluoroquinolones on clinical outcome in critically ill patients. The findings from the DOLPHIN trial will possibly lead to new insights in clinical management of critically ill patients receiving antibiotics. In short, to TDM or not to TDM? TRIAL REGISTRATION: EudraCT number: 2017-004677-14. Sponsor protocol name: DOLPHIN. Registered 6 March 2018 . Protocol Version 6, Protocol date: 27 November 2019.

A population pharmacokinetic model to predict the individual starting dose of tacrolimus in adult renal transplant recipients.

AIMS: The aims of this study were to describe the pharmacokinetics of tacrolimus immediately after kidney transplantation, and to develop a clinical tool for selecting the best starting dose for each patient. METHODS: Data on tacrolimus exposure were collected for the first 3 months following renal transplantation. A population pharmacokinetic analysis was conducted using nonlinear mixed-effects modelling. Demographic, clinical and genetic parameters were evaluated as covariates. RESULTS: A total of 4527 tacrolimus blood samples collected from 337 kidney transplant recipients were available. Data were best described using a two-compartment model. The mean absorption rate was 3.6 h-1 , clearance was 23.0 l h-1 (39% interindividual variability, IIV), central volume of distribution was 692 l (49% IIV) and the peripheral volume of distribution 5340 l (53% IIV). Interoccasion variability was added to clearance (14%). Higher body surface area (BSA), lower serum creatinine, younger age, higher albumin and lower haematocrit levels were identified as covariates enhancing tacrolimus clearance. Cytochrome P450 (CYP) 3A5 expressers had a significantly higher tacrolimus clearance (160%), whereas CYP3A4*22 carriers had a significantly lower clearance (80%). From these significant covariates, age, BSA, CYP3A4 and CYP3A5 genotype were incorporated in a second model to individualize the tacrolimus starting dose: [Formula: see text] Both models were successfully internally and externally validated. A clinical trial was simulated to demonstrate the added value of the starting dose model. CONCLUSIONS: For a good prediction of tacrolimus pharmacokinetics, age, BSA, CYP3A4 and CYP3A5 genotype are important covariates. These covariates explained 30% of the variability in CL/F. The model proved effective in calculating the optimal tacrolimus dose based on these parameters and can be used to individualize the tacrolimus dose in the early period after transplantation.

Personalized immunosuppression in elderly renal transplant recipients.

The number of elderly people has increased considerably over the last decades, due to a rising life expectancy and ageing populations. As a result, an increased number of elderly with end-stage-renal-disease are diagnosed, for which the preferred treatment is renal transplantation. Over the past years the awareness of the elderly as a specific patient population has grown, which increases the importance of research in this group. Elderly patients often receive kidneys from elderly donors while younger donor kidneys are preferentially reserved for younger recipients. Although the rate of acute rejection after transplantation is lower in the elderly, these rejections may lead to graft loss more frequently, as kidneys from elderly donors have marginal reserve capacity. To prevent acute rejection, immunosuppressive therapy is needed. On the other hand, elderly patients have a higher risk to die from infectious complications, and thus less immunosuppression would be preferable. Immunosuppressive treatment in the elderly is complicated further by changes in the pharmacokinetics and pharmacodynamics, with increasing age. Adjustments in standard immunosuppressive regimes are therefore suggested for this population. An unmet need in transplantation medicine is a tool to guide a personalized approach to immunosuppression. Recently several promising biomarkers that identify injury to the graft at an early stage or predict acute rejection have been identified. Unfortunately, none of these biomarkers were tested specifically in the elderly. We believe there is an urgent need to perform clinical trials investigating novel immunosuppressive regimens in conjunction with biomarker studies in this specific population.

Effects of training physicians in electronic prescribing in the outpatient setting on clinical, learning and behavioural outcomes: a cluster randomized trial.

AIMS: Electronic prescribing systems may improve medication safety, but only when used appropriately. The effects of task analysis-based training on clinical, learning and behavioural outcomes were evaluated in the outpatient setting, compared with the usual educational approach. METHODS: This was a multicentre, cluster randomized trial [EDUCATional intervention for IT-mediated MEDication management (MEDUCATE trial)], with physicians as the unit of analysis. It took place in the outpatient clinics of two academic hospitals. Participants comprised specialists and residents (specialty trainees, in the UK) and their patients. Training took the form of a small-group session and an e-learning. The primary outcome was the proportion of medication discrepancies per physician, measured as discrepancies between medications registered by physicians in the electronic prescribing system and those reported by patients. Clinical consequences were estimated by the proportion of patients per physician with at least one missed drug-drug interaction with the potential for causing adverse drug events. A questionnaire assessed physicians' knowledge and skills. RESULTS: Among 124 participating physicians, primary outcome data for 115 (93%) were available. A total of 1094 patients were included. A mean of 48% of registered medications per physician were discrepant with the medications that their patients reported in both groups (P = 0.14). Due to registration omissions, a mean of 4% of patients per physician had one or more missed drug-drug interactions with the potential to cause a clinically relevant adverse drug event in the intervention group, and 7% in controls (P = 0.11). The percentages of correct answers on the knowledge and skills test were higher in the intervention group (57%) compared with controls (51%; P = 0.01). CONCLUSION: The training equipped outpatient physicians with the knowledge and skills for appropriate use of electronic prescribing systems, but had no effect on medication discrepancies.

Drug-drug interactions in pediatric oncology patients.

BACKGROUND: Drug-drug interactions (DDIs) can negatively affect pharmacotherapy. However, pediatric DDI studies are scarce. We undertook an exploratory study to investigate prevalence and clinical relevance of DDIs between cytostatic and noncytostatic drugs in outpatient pediatric oncology patients. PROCEDURE: After informed consent and inclusion, the following information was collected: currently prescribed noncytostatic and cytostatic drugs, comorbidities, and use of over-the-counter (OTC) drugs, complementary and alternative medicines (CAMs), and dietary supplements. All medication was screened for DDIs according to two databases: Micromedex® Solutions and the Dutch drug database G-Standard. The researcher presented DDIs with an associated potential for adverse outcome and a proposal for intervention to three independent experts. If the experts considered a DDI to be potentially clinically relevant and requiring intervention, the physician was notified. RESULTS: Seventy-three patients were included (median age 8.9 years). A total of 67 different DDIs were counted (66 in Micromedex® Solutions, 14 in G-Standard, and 13 DDIs in both databases). The medication reviews resulted in 35 interventions related to 11 different DDIs. The majority of DDIs concerned noncytostatic drugs (25/35) and one third occurred between cytostatic and noncytostatic drugs (10/35). The use of QTc-interval-prolonging drugs resulted in one intervention. The use of OTC drugs, CAM, or dietary supplements did not lead to DDIs. CONCLUSIONS: This study resulted in a selection of 11 potentially clinically relevant DDIs for 73 outpatients in our pediatric oncology department. Interventions were formulated in close collaboration between physicians and clinical pharmacists. Future research should focus on assessing DDIs concerning QTc-interval prolongation.

Population pharmacokinetics of haloperidol in terminally ill adult patients.

PURPOSE: Over 80% of the terminally ill patients experience delirium in their final days. In the treatment of delirium, haloperidol is the drug of choice. Very little is known about the pharmacokinetics of haloperidol in this patient population. We therefore designed a population pharmacokinetic study to gain more insight into the pharmacokinetics of haloperidol in terminally ill patients and to find clinically relevant covariates that may be used in developing an individualised dosing regimen. METHODS: Using non-linear mixed effects modelling (NONMEM 7.2), a population pharmacokinetic analysis was conducted with 87 samples from 28 terminally ill patients who received haloperidol either orally or subcutaneously. The covariates analysed were patient and disease characteristics as well as co-medication. RESULTS: The data were accurately described by a one-compartment model. The population mean estimates for oral bioavailability, clearance and volume of distribution for an average patient were 0.86 (IIV 55%), 29.3 L/h (IIV 43%) and 1260 L (IIV 70%), respectively. This resulted in an average terminal half-life of haloperidol of around 30 h. CONCLUSION: Our study showed that the pharmacokinetics of haloperidol could be adequately described by a one-compartment model. The pharmacokinetics in terminally ill patients was comparable to other patients. We were not able to explain the wide variability using covariates.

A Randomized Controlled Trial Comparing the Efficacy of Cyp3a5 Genotype-Based With Body-Weight-Based Tacrolimus Dosing After Living Donor Kidney Transplantation.

Patients expressing the cytochrome P450 (CYP) 3A5 gene require a higher tacrolimus dose to achieve therapeutic exposure compared with nonexpressers. This randomized-controlled study investigated whether adaptation of the tacrolimus starting dose according to CYP3A5 genotype increases the proportion of kidney transplant recipients being within the target tacrolimus predose concentration range (10-15 ng/mL) at first steady-state. Two hundred forty living-donor, renal transplant recipients were assigned to either receive a standard, body-weight-based or a CYP3A5 genotype-based tacrolimus starting dose. At day 3, no difference in the proportion of patients having a tacrolimus exposure within the target range was observed between the standard-dose and genotype-based groups: 37.4% versus 35.6%, respectively; p = 0.79. The proportion of patients with a subtherapeutic (i.e. <10 ng/mL) or a supratherapeutic (i.e. >15 ng/mL) Tac predose concentration in the two groups was also not significantly different. The incidence of acute rejection was comparable between both groups (p = 0.82). Pharmacogenetic adaptation of the tacrolimus starting dose does not increase the number of patients having therapeutic tacrolimus exposure early after transplantation and does not lead to improved clinical outcome in a low immunological risk population.

Drug-drug interactions in patients treated for cancer: a prospective study on clinical interventions.

BACKGROUND: Drug-drug interactions (DDIs) are of major concern in oncology, since cancer patients typically take many concomitant medications. Retrospective studies have been conducted to determine the prevalence of DDIs. However, prospective studies on DDIs needing interventions in cancer patients have not yet been carried out. Therefore, a prospective study was designed to identify DDIs leading to interventions among ambulatory cancer patients receiving anticancer treatment. PATIENTS AND METHODS: Patients starting with a new treatment regimen with i.v. or oral anticancer medication were asked to participate. The patients' medication was checked for DDIs by using drug interaction software. An expert team of clinical pharmacologists evaluated the relevance of these identified DDIs. If a DDI was qualified as potentially clinically relevant, an intervention was proposed to the treating (hemato)oncologist. Several variables were studied as determinants for performing an intervention. Descriptive statistics and uni- and multivariate logistic regression analyses were carried out. RESULTS: In this study, 302 patients were included. A total of 603 DDIs were identified by the drug interaction software and judged by the expert team. Of all 603 DDIs, 120 DDIs were considered potentially clinically relevant. These 120 DDIs, present in a total of 81 patients, resulted in a clinical intervention already executed by the (hemato)oncologist in 39 patients (13%), while an additional intervention was proposed by a clinical pharmacologist in 42 patients (14%). The number of comorbidities and the number of 'over-the-counter' drugs were identified as determinants. CONCLUSIONS: Clinical interventions on DDIs are frequently required among patients starting with anticancer therapy. Structured screening for these potentially clinically relevant DDIs, by (hemato)oncologists in close collaborations with clinical pharmacologists, should take place before the start and during anticancer treatment. CLINICAL TRIALS NUMBER: This study was registered at the Dutch Trial Registry under number NTR3760.

Task analysis of information technology-mediated medication management in outpatient care.

AIMS: Educating physicians in the procedural as well as cognitive skills of information technology (IT)-mediated medication management could be one of the missing links for the improvement of patient safety. We aimed to compose a framework of tasks that need to be addressed to optimize medication management in outpatient care. METHODS: Formal task analysis: decomposition of a complex task into a set of subtasks. First, we obtained a general description of the medication management process from exploratory interviews. Secondly, we interviewed experts in-depth to further define tasks and subtasks. SETTING: Outpatient care in different fields of medicine in six teaching and academic medical centres in the Netherlands and the United States. PARTICIPANTS: 20 experts. Tasks were divided up into procedural, cognitive and macrocognitive tasks and categorized into the three components of dynamic decision making. RESULTS: The medication management process consists of three components: (i) reviewing the medication situation; (ii) composing a treatment plan; and (iii) accomplishing and communicating a treatment and surveillance plan. Subtasks include multiple cognitive tasks such as composing a list of current medications and evaluating the reliability of sources, and procedural tasks such as documenting current medication. The identified macrocognitive tasks were: planning, integration of IT in workflow, managing uncertainties and responsibilities, and problem detection. CONCLUSIONS: All identified procedural, cognitive and macrocognitive skills should be included when designing education for IT-mediated medication management. The resulting framework supports the design of educational interventions to improve IT-mediated medication management in outpatient care.

Cognitive processes in pharmacists' clinical decision-making.

BACKGROUND: Pharmacists' clinical decision-making is a core process in pharmaceutical care. However, the practical aspects and effective teaching methods of this process remain largely unexplored. OBJECTIVE: To examine the cognitive processes involved in pharmacists' perceptions of how they make clinical decisions in pharmacy practice. METHODS: Semi-structured, face-to-face interviews were conducted with pharmacists working in community, outpatient, and hospital care in the Netherlands between August and December 2021. Participants were explicitly asked for examples when asked how they make clinical decisions in practice and how they teach this to others. After transcribing audio-recorded interviews, an inductive thematic analysis was conducted to identify cognitive processes. A theoretical model of clinical decision-making was then used and adapted to structure the identified processes. RESULTS: In total, 21 cognitive processes were identified from interviews with 16 pharmacists working in community (n = 5), outpatient (n = 2), and hospital care (n = 9). These cognitive processes were organized into 8 steps of the adapted theoretical model, i.e. problem and demand for care consideration, information collection, clinical reasoning, clinical judgment, shared decision-making, implementation, outcomes evaluation, and reflection. Pharmacists struggled to articulate their clinical decision-making and went back-and-forth in their explanations of this process. All pharmacists emphasized the importance of identifying the problem and described how they collect information through reviewing, gathering, recalling, and investigating. Clinical reasoning entailed various cognitive processes, of which comprehending the problem in the patient's context was deemed challenging at times. Pharmacists seemed least active in evaluating patient outcomes and reflecting on these outcomes. CONCLUSIONS: Pharmacists use multiple cognitive processes when making clinical decisions in pharmacy practice, and their back-and-forth explanations emphasize its dynamic nature. This study adds to a greater understanding of how pharmacists make clinical decisions and to the development of a theoretical model that describes this process, which can be used in pharmacy practice and education.

Antihypertensive drug concentration measurement combined with personalized feedback in resistant hypertension: a randomized controlled trial.

BACKGROUND: Adherence to antihypertensive drugs (AHDs) is crucial for controlling blood pressure (BP). We aimed to determine the effectiveness of measuring AHD concentrations using a dried blood spot (DBS) sampling method to identify nonadherence, combined with personalized feedback, in reducing resistant hypertension. METHODS: We conducted a multicenter, randomized, controlled trial (RHYME-RCT, ICTRP NTR6914) in patients with established resistant hypertension. Patients were randomized to receive either an intervention with standard of care (SoC) or SoC alone. SoC consisted of BP measurement and DBS sampling at baseline, 3 months (t3), 6 months (t6), and 12 months (t12); AHD concentrations were measured but not reported in this arm. In the intervention arm, results on AHD concentrations were discussed during a personalized feedback conversation at baseline and t3. Study endpoints included the proportion of patients with RH and AHD adherence at t12. RESULTS: Forty-nine patients were randomized to receive the intervention+SoC, and 51 were randomized to receive SoC alone. The proportion of adherent patients improved from 70.0 to 92.5% in the intervention+SoC arm ( P  = 0.008, n  = 40) and remained the same in the SoC arm (71.4%, n  = 42). The difference in adherence between the arms was statistically significant ( P  = 0.014). The prevalence of resistant hypertension decreased to 75.0% in the intervention+SoC arm ( P  < 0.001, n  = 40) and 59.5% in the SoC arm ( P  < 0.001, n  = 42) at t12; the difference between the arms was statistically nonsignificant ( P  = 0.14). CONCLUSION: Personalized feedback conversations based on DBS-derived AHD concentrations improved AHD adherence but did not reduce the prevalence of RH.

Prevalence of potential drug-drug interactions in cancer patients treated with oral anticancer drugs.

BACKGROUND: Potential drug-drug interactions (PDDIs) in patients with cancer are common, but have not previously been quantified for oral anticancer treatment. We assessed the prevalence and seriousness of potential PDDIs among ambulatory cancer patients on oral anticancer treatment. METHODS: A search was conducted in a computer-based medication prescription system for dispensing oral anticancer drugs to outpatients in three Dutch centres. Potential drug-drug interactions were identified using electronic (Drug Interaction Fact software) and manual screening methods (peer-reviewed reports). RESULTS: In the 898 patients included in the study, 1359 PDDIs were identified in 426 patients (46%, 95% confidence interval (CI)=42-50%). In 143 patients (16%), a major PDDI was identified. The drug classes most frequently involved in a major PDDI were coumarins and opioids. The majority of cases concerned central nervous system interactions, PDDIs that can cause gastrointestinal toxicity and prolongation of QT intervals. In multivariate analysis, concomitant use of more drugs (odds ratio (OR)=1.66, 95% CI=1.54-1.78, P<0001) and genito-urinary cancer (OR=0.25, 95% CI=0.12-0.52, P<0001) were risk factors. CONCLUSION: Potential drug-drug interactions are very common among cancer patients on oral cancer therapy. Physicians and pharmacists should be more aware of these potential interactions.

Tacrolimus predose concentrations do not predict the risk of acute rejection after renal transplantation: a pooled analysis from three randomized-controlled clinical trials(†).

Therapeutic drug monitoring (TDM) for tacrolimus (Tac) is universally applied. However, the concentration-effect relationship for Tac is poorly defined. This study investigated whether Tac concentrations are associated with acute rejection in kidney transplant recipients. Data from three large trials were pooled. We used univariate and multivariate analysis to investigate the relationship between biopsy-proven acute rejection (BPAR) and Tac predose concentration at five time points (day 3, 10 and 14, and month 1 and 6 after transplantation). A total of 136/1304 patients experienced BPAR, giving an overall incidence of 10.4%. We did not find any significant correlations between Tac predose concentrations and the incidence of BPAR at the different time points. In the multivariate analysis, only delayed graft function (DGF) and the use of induction therapy were independently correlated with BPAR, with an odds ratio of 2.7 [95% CI: 1.8-4.0; p < 0.001] for DGF and 0.66 [95% CI: 0.44-0.99; p = 0.049] for induction therapy. The other variables, including the Tac predose concentrations, were not statistically significantly associated with BPAR. We did not find an association between the Tac predose concentrations measured at five time points after kidney transplantation and the incidence of acute rejection occurring thereafter. Based on this study it is not possible to define the optimal target concentrations for Tac.

Treatment of a life-threatening dapsone intoxication.

The case report describes a case of a severe dapsone (more than 200 tablets dapsone 100 mg) and mild methotrexate intoxication (10 tablets methotrexate 10 mg) as an attempt to commit suicide, resulting in severe cyanosis with elevation in methemoglobin concentration, treated with methylene blue, ascorbic acid, folinic acid, multidose activated charcoal and hemodialysis. Measurements of blood gases, dapsone and methotrexate levels were performed. Furthermore a hepatitis, pulmonary artery thrombus and a strange taste sensation were diagnosed, probably related to dapsone. The patient recovered and was discharged from hospital after five days. Acute intoxication from excessive dapsone intake is uncommon and clear treatment guidelines are lacking. We here report the treatment modalities as a result of a dapsone intoxication, including the effects on the overall condition of the patient.

Factors influencing pharmacists' clinical decision making in pharmacy practice.

BACKGROUND: Pharmacists' clinical decision-making is considered a core process of pharmaceutical care in pharmacy practice, but little is known about the factors influencing this process. OBJECTIVE: To identify factors influencing clinical decision-making among pharmacists working in pharmacy practice. METHODS: Semi-structured interviews were conducted with pharmacists working in primary, secondary, and tertiary care settings in the Netherlands between August and December 2021. A thematic analysis was conducted using an inductive approach. The emerged themes were categorized into the Capability-Opportunity-Motivation-Behaviour (COM-B) model domains. RESULTS: In total, 16 pharmacists working in primary care (n = 7), secondary care (n = 4) or tertiary care (n = 5) were interviewed. Factors influencing pharmacists' capability to make clinical decisions are a broad theoretical knowledge base, clinical experience, and skills, including contextualizing data, clinical reasoning, and clinical judgment. The pharmacy setting, data availability, rules and regulations, intra- and interprofessional collaboration, education, patient perspectives, and time are mentioned as factors influencing their opportunity. Factors influencing pharmacists' motivation are confidence, curiosity, critical thinking, and responsibility. CONCLUSIONS: The reported factors covered all domains of the COM-B model, implying that clinical decision-making is influenced by a combination of pharmacists' capability, opportunity, and motivation. Addressing these different factors in pharmacy practice and education may improve pharmacists' clinical decision-making, thereby improving patient outcomes.