The effect of a Clinical Decision Support System on the frequency of dose adjustments of anticancer drugs in case of renal or hepatic dysfunction.

INTRODUCTION: Dose adjustments in patients with renal or hepatic dysfunction using anticancer drugs are indicated according to guidelines. However, implementation depends on awareness of prescribing physicians. We implemented a Clinical Decision Support System (CDSS), recommending dose adjustments upon electronic prescriptions based on renal and hepatic function. The alert provides a dose adjustment proposal and recent laboratory results. Our objective was to determine the frequency of dose adjustments before and after implementation of this CDSS. METHODS: We included all first orders for patients ≥18 years treated with parenteral antineoplastic agents, for whom dosage adjustment is necessary based on renal or hepatic function between February 2018 and January 2019. This study was performed at the department of Clinical Oncology and Hematology of the Amsterdam University Medical Center. We implemented the CDSS August first. All prescriptions were prescribed according to common practice. We analyzed the orders where a dose reduction based on renal or hepatic function was indicated. RESULTS: We included 73 orders before implementation and 99 orders after implementation. Before implementation 21% of doses were reduced in line with the guidelines versus 34% after implementation (p = 0.048). For hepatic dysfunction the proportion changed from 11% to 46% p = 0.011, while there was no effect for renal dysfunction (24% vs. 26% p = 0.75). CONCLUSION: Dosages are more frequently adjusted in concordance with guidelines in patients with hepatic dysfunction who are treated with parenteral antineoplastic agents after implementation of a CDSS. The change was not seen in patients with renal dysfunction.

Unintentional guideline deviations in hospitalized patients with two or more antithrombotic agents: an intervention study.

PURPOSE: Treatment schedules for antithrombotic therapy are complex, and there is a risk of inappropriate prescribing or continuation of antithrombotic therapy beyond the intended period of time. The primary aim of this study was to determine the frequency of unintentional guideline deviations in hospitalized patients. Secondary aims were to determine whether the frequency of unintentional guideline deviations decreased after intervention by a pharmacist, to determine the acceptance rate of the interventions and to determine the type of interventions. METHODS: We performed a non-controlled prospective intervention study in three teaching hospitals in the Netherlands. We examined whether hospitalized patients who used the combination of an anticoagulant plus at least one other antithrombotic agent had an unintentional guideline deviation. In these cases, the hospital pharmacist contacted the physician to assess whether this deviation was intentional. If the deviation was unintentional, a recommendation was provided how to adjust the antithrombotic regimen according to guideline recommendations. RESULTS: Of the 988 included patients, 407 patients had an unintentional guideline deviation (41.2%). After intervention, this was reduced to 22 patients (2.2%) (p < 0.001). The acceptance rate of the interventions was 96.6%. The most frequently performed interventions were discontinuation of an low molecular weight heparin in combination with a direct oral anticoagulant and discontinuation of an antiplatelet agent when there was no indication for the combination of an antiplatelet agent and an anticoagulant. CONCLUSION: A significant number of hospitalized patients who used an anticoagulant plus one other antithrombotic agent had an unintentional guideline deviation. Intervention by a pharmacist decreased unintentional guideline deviations.

Guidelines for mono, double and triple antithrombotic therapy.

Guidelines for antithrombotic therapy are complex, especially if a patient has several indications that require antithrombotic therapy. In general, no patient should receive lifelong double or triple antithrombotic therapy. In this overview, we outline the most common indications for mono, double and triple antithrombotic therapy; the preferred antithrombotic therapy and the recommended duration of therapy. Both antiplatelet therapy and therapeutic anticoagulation therapy with vitamin K antagonists or direct oral anticoagulants were included. European guidelines were used or, if no European guidelines were available, the Dutch guidelines were used.

Dose recommendations for gentamicin in the real-world obese population with varying body weight and renal (dys)function.

BACKGROUND: The impact of weight on pharmacokinetics of gentamicin was recently elucidated for (morbidly) obese individuals with normal renal function. OBJECTIVES: To characterize the pharmacokinetics of gentamicin in real-world obese patients, ultimately to develop dose recommendations applicable across the entire obese population. METHODS: In two large Dutch hospitals, all admitted patients with BMI ≥25 kg/m2 with at least one gentamicin administration, at least one gentamicin and at least one creatinine serum concentration measurement were included. Data from one hospital, obtained from electronic health records, combined with prospective data of non-obese and morbidly obese people with normal renal function, served as the training dataset, and data from the second hospital served as the external validation dataset. RESULTS: In the training dataset [1187 observations from 542 individuals, total body weight (TBW) 52-221 kg and renal function (CKD-EPI) 5.1-141.7 mL/min/1.73 m2], TBW was identified as a covariate on distribution volume, and de-indexed CKD-EPI and ICU stay on clearance (all P < 0.001). Clearance was 3.53 L/h and decreased by 0.48 L/h with each 10 mL/min reduction in de-indexed CKD-EPI. The results were confirmed in the external validation (321 observations from 208 individuals, TBW 69-180 kg, CKD-EPI 5.3-130.0 mL/min/1.73 m2). CONCLUSIONS: Based on the study, we propose specific mg/kg dose reductions with decreasing CKD-EPI values for the obese population, and extension of the dosing interval beyond 24 h when CKD-EPI drops below 50 mL/min/1.73 m2. In ICU patients, a 25% dose reduction could be considered. These guidelines can be used to guide safe and effective dosing of gentamicin across the real-world obese population.

Drug-drug interactions with metronidazole and itraconazole in patients using acenocoumarol.

PURPOSE: Various population-based cohort studies have shown that antimicrobial agents increase the risk of overanticoagulation in patients using coumarins. In this study, we assessed this association in hospitalized patients. METHODS: We included all patients hospitalized in the Spaarne Gasthuis (Haarlem/Hoofddorp, the Netherlands), who started using an antimicrobial agent during acenocoumarol treatment or vice versa between 1 January 2015 and 1 July 2019. Patients were followed from start of concomitant therapy until 48 h after termination of the concomitant therapy or discharge, whichever came first. We analyzed the association between the antimicrobial agents and the risk of overanticoagulation, defined as an interpolated INR above 6, using Cox regression analysis. We corrected for multiple testing with the Bonferroni correction. Patients who started using acenocoumarol and amoxicillin/clavulanic acid were used as reference group. RESULTS: In the study population, sixteen antimicrobial agents were started frequently concomitantly with acenocoumarol treatment. We included 2157 interaction episodes in 1172 patients. Patients who started using the combination of co-trimoxazole (HR 3.76; 95% CI 1.47-9.62; p = 0.006), metronidazole (HR 2.55; 95% CI 1.37-4.76; p = 0.003), or itraconazole (HR 4.11; 95% CI 1.79-9.45; p = 0.001) concomitantly with acenocoumarol treatment had an increased risk of overanticoagulation compared with patients using acenocoumarol and amoxicillin/clavulanic acid concomitantly. The associations for metronidazole (p = 0.045) and itraconazole (p = 0.015) remained statistically significant after correction for multiple testing. CONCLUSION: Co-trimoxazole, metronidazole, and itraconazole increase the risk of overanticoagulation in patients using acenocoumarol. These combinations should be avoided if possible or otherwise acenocoumarol doses should be reduced and INR measured more frequently.

Development and validation of a tool to assess the risk of QT drug-drug interactions in clinical practice.

BACKGROUND: The exact risk of developing QTc-prolongation when using a combination of QTc-prolonging drugs is still unknown, making it difficult to interpret these QT drug-drug interactions (QT-DDIs). A tool to identify high-risk patients is needed to support healthcare providers in handling automatically generated alerts in clinical practice. The main aim of this study was to develop and validate a tool to assess the risk of QT-DDIs in clinical practice. METHODS: A model was developed based on risk factors associated with QTc-prolongation determined in a prospective study on QT-DDIs in a university medical center inthe Netherlands. The main outcome measure was QTc-prolongation defined as a QTc interval > 450 ms for males and > 470 ms for females. Risk points were assigned to risk factors based on their odds ratios. Additional risk factors were added based on a literature review. The ability of the model to predict QTc-prolongation was validated in an independent dataset obtained from a general teaching hospital against QTc-prolongation as measured by an ECG as the gold standard. Sensitivities, specificities, false omission rates, accuracy and Youden's index were calculated. RESULTS: The model included age, gender, cardiac comorbidities, hypertension, diabetes mellitus, renal function, potassium levels, loop diuretics, and QTc-prolonging drugs as risk factors. Application of the model to the independent dataset resulted in an area under the ROC-curve of 0.54 (95% CI 0.51-0.56) when QTc-prolongation was defined as > 450/470 ms, and 0.59 (0.54-0.63) when QTc-prolongation was defined as > 500 ms. A cut-off value of 6 led to a sensitivity of 76.6 and 83.9% and a specificity of 28.5 and 27.5% respectively. CONCLUSIONS: A clinical decision support tool with fair performance characteristics was developed. Optimization of this tool may aid in assessing the risk associated with QT-DDIs. TRIAL REGISTRATION: No trial registration, MEC-2015-368.

QTc prolongation during ciprofloxacin and fluconazole combination therapy: prevalence and associated risk factors.

AIM(S): Ciprofloxacin and fluconazole combination therapy is frequently used as prophylaxis for, and treatment of, infections in patients with haematological malignancies. However, both drugs are known to prolong the heart rate-corrected QT (QTc) interval, which is a serious risk factor for torsade de pointes (TdP). Therefore, the aim of the current study was to assess the prevalence of QTc prolongation during ciprofloxacin and fluconazole use. The secondary objective was to determine associated risk factors of QTc prolongation in these patients. METHODS: A prospective observational study was performed in patients admitted to the Erasmus University Medical Centre and treated with ciprofloxacin and fluconazole. A 12-lead electrocardiogram (ECG) was recorded at the estimated time to peak concentration (Tmax ) for the last added drug. The main outcome was the proportion of patients with QTc prolongation during treatment. Data on the following potential risk factors were collected: patient characteristics, serum electrolyte levels, dosage of ciprofloxacin and fluconazole, renal and liver function and concomitant use of other QTc-prolonging drugs and cytochrome P450 3A4 inhibitors. RESULTS: A total of 170 patients were included, of whom 149 (87.6%) were treated for haematological malignancies. The prevalence of QTc prolongation was 4.7%. No risk factors were found to be associated with QTc prolongation. The QTc interval increased by 10.7 ms [95% confidence interval (CI) 7.2, 14.1 ms] during ciprofloxacin and fluconazole combination therapy. CONCLUSION: The prevalence of QTc prolongation in patients using ciprofloxacin and fluconazole is low compared with the prevalence in the general population, which varies from 5% to 11%. In addition, no risk factors were found. Given the low prevalence, routine ECG monitoring in patients on this therapy should be reconsidered.

Risk factors for QTc interval prolongation.

PURPOSE: Prolongation of the QTc interval may result in Torsade de Pointes, a ventricular arrhythmia. Numerous risk factors for QTc interval prolongation have been described, including the use of certain drugs. In clinical practice, there is much debate about the management of the risks involved. In this study, we quantified the effect of these risk factors on the length of the QTc interval. METHODS: We analyzed all ECGs that were taken during routine practice between January 2013 and October 2016 in the Spaarne Gasthuis, a general teaching hospital in the Netherlands. We collected laboratory values in the week before the ECG recording and the drugs prescribed. For the identification of risk factors, we used multilevel linear regression analysis to correct for multiple ECG recordings per patient. RESULTS: We included 133,359 ECGs in our study, taken in 40,037 patients. Patients using one QT-prolonging drug had a 11.08 ms (95% CI 10.63-11.52; p < 0.001) longer QTc interval. Patients using two QT-prolonging drugs had a 3.04 ms (95% CI 2.06-4.02; p < 0.001) increase in the QTc interval compared to patients using one QT-prolonging drug. Women had a longer QTc interval compared to men (16.30 ms 95% CI 14.59-18.01; p < 0.001). The QTc interval increased with increasing age, but the difference between men and women diminished. Other independent risk factors that significantly prolonged the QTc interval with at least 10 ms were hypokalemia, hypocalcemia, and the use of loop diuretics. CONCLUSION: We identified and quantified various risk factors for QTc interval prolongation.

Physicians' Compliance with a Clinical Decision Support System Alerting during the Prescribing Process.

Clinical decision support systems have been shown to improve practitioner performance. Most systems designed to prevent medication errors generate lists with patients who fulfill the criteria of the algorithm. These lists are reviewed by a pharmacist and physicians are contacted by telephone. Presenting pop-up alerts as part of the workflow with a clear recommendation is a feature critical to success. Therefore we implemented three algorithms in a clinical decision support system alerting during the medication ordering process. We analyzed whether the recommendations in these alerts were followed. We evaluated 1. whether folic or folinic acid was co-prescribed more frequently within 48 h after ordering methotrexate, 2. whether vitamin D or analogues were co-prescribed more frequently within 48 h after ordering bisphophonates and 3. whether sodium lowering drugs were stopped more frequently within one hour in patients with hyponatremia. We analyzed the difference in the 48 days before implementation and the 43 days after implementation, using Pearson's Chi2 test. Co-prescription of folic or folinic acid increased from 54 to 91% (p = 0.014), co-prescription of vitamin D or analogues increased from 11 to 40% (p = 0.001) and the number of stopped orders for sodium lowering drugs increased from 3 to 14% (p = 0.002). This clinical decision support system that alerts physicians for preventable medication errors during the medication ordering process is an effective approach to improve prescribing behavior.

The rs13064411 polymorphism in the WDR52 gene, associated with PCSK9 levels, modifies statin-induced changes in serum total and LDL cholesterol levels.

OBJECTIVE: Recently, the minor allele of the rs13064411A>G polymorphism in the WD repeat domain 52 (WDR52) gene was associated with increased statin-induced proprotein convertase subtilisin/kexin type 9 (PCSK9) levels and with LDL cholesterol response to statins. PCSK9 promotes LDL receptor degradation, leading to increased serum LDL cholesterol. We investigated whether the polymorphism was associated with cholesterol response to statins. METHODS: We identified 1105 current, 322 past, and 4831 never statin users during follow-up in the prospective population-based Rotterdam Study. The mean delta total, LDL, and HDL cholesterol levels between current and no current statin users with the same number of minor alleles were analyzed using random-effect repeated measurements. We adjusted for age, sex, number of cholesterol measurements, and follow-up time. RESULTS: Compared with no users with the same genotype, current statin users carrying a minor allele showed a statistically significantly lower delta total and LDL cholesterol compared with reference homozygous major allele carriers [total: Δ=0.551 mmol/l (AG+GG) vs. Δ=0.732 mmol/l (AA), Pinteraction: 5.2×10(-7); LDL: Δ=0.566 mmol/l (AG+GG) vs. Δ=0.720 mmol/l (AA), Pinteraction: 1.8×10(-5)]. The effect was stronger in women (Pinteraction: 2.0×10(-5) for LDL cholesterol, 8.0×10(-6) for total cholesterol) and in high-dose users (defined daily doses>1.00) (Pinteraction: 7.0×10(-5) for LDL cholesterol, Pinteraction: 0.081 for total cholesterol). The polymorphism was not associated with HDL cholesterol in current statin users, or with total, LDL and HDL cholesterol in never statin users. CONCLUSION: The minor G allele of the rs13064411 polymorphism, associated with statin-induced PCSK9-levels, was associated with a decreased LDL-lowering and total cholesterol-lowering response to statins.

The SLCO1B1 c.521T>C polymorphism is associated with dose decrease or switching during statin therapy in the Rotterdam Study.

OBJECTIVE: The SLCO1B1 c.521T>C polymorphism is associated with statin plasma levels and simvastatin-induced adverse drug reactions. We studied whether the c.521T>C polymorphism is associated with dose decreases or switches to other cholesterol-lowering drugs during simvastatin and atorvastatin therapy, because these events are indicators of adverse drug reactions. MATERIALS AND METHODS: We identified 1939 incident simvastatin and atorvastatin users in the Rotterdam Study, a population-based cohort study. Associations were studied using Cox proportional hazards analysis. Meta-analysis was performed with data from the Utrecht Cardiovascular Pharmacogenetics study. RESULTS: Simvastatin users with the c.521 CC genotype had a significantly higher risk of a dose decrease or switch than users with the TT genotype [hazard ratio (HR) 1.74, 95% confidence interval (CI) 1.05-2.88]. Female sex, age below 70 years, and low starting dose were risk factors. In atorvastatin users with starting dose of more than 20 mg, the risk of a dose decrease or switch was higher in users carrying a C allele than in users with the TT genotype (HR 3.26, 95% CI 1.47-7.25). In the meta-analysis the association in simvastatin users remained, with a significantly higher risk of a dose decrease or switch in simvastatin users with two minor alleles (HR 1.69, 95% CI 1.05-2.73). For atorvastatin users no significant association was found. CONCLUSION: In simvastatin users in the Rotterdam Study, we demonstrated an association between the c.521T>C polymorphism and dose decrease or switching, as indicators of adverse drug reactions, and provided risk factors for this association. For atorvastatin, an association was found in users with a starting dose of more than 20 mg.

A quality improvement study on the effect of electronic transmission of a basic discharge medication report on medication discrepancies in patients discharged from the hospital.

BACKGROUND: Medication discrepancies can occur in transitions of care because of a lack of communication between hospitals and community pharmacies. These discrepancies can lead to preventable adverse drug events (ADEs). AIM: To investigate the effect of electronic transmission of the basic discharge medication report on unintentional medication discrepancies observed between this report and the 28-day post-discharge status in the community pharmacy. METHOD: The study took place in a Dutch teaching hospital and 8 community pharmacies. A quality improvement study with a nonrandomized, historically controlled intervention design was performed. The intervention consisted of the electronic transmission of a basic discharge medication report to the community pharmacies. Unintentional medication discrepancies were identified by comparing the basic discharge medication report to the 28-day post-discharge medication record in community pharmacies. The main outcome measure was the proportion of drugs with one or more unintentional discrepancies compared between the historical control group and intervention group, using the chi-square test. Secondary outcome measure was the proportion of patients with one or more unintentional discrepancies. RESULTS: The participants used a total of 1078 drugs in the control group and 862 in the intervention group. The intervention significantly reduced the proportion of drugs with an unintentional discrepancy from 230 out of 1078 in the control group (21.3%) to 149 out of 862 drugs in the intervention group (17.3%; p = 0.025). At patient level, a non-significant increase was seen (62.4-78.8%; p = 0.41). CONCLUSION: The electronic transmission of the basic discharge medication report reduced the proportion of drugs with an unintentional discrepancy after discharge, but not the proportion of patients.

Antithrombotic Questionnaire Tool for Evaluation of Combined Antithrombotic Therapy in Community Pharmacies.

OBJECTIVE: The objective of this paper is to assess the diagnostic value of an antithrombotic questionnaire tool compared with the hospital's medical record information tool. The hypothesis of this study was that the antithrombotic questionnaire tool could identify patients with potentially incorrect antithrombotic therapy. METHODS: This cross-sectional study was conducted in eight community pharmacies in the Netherlands. A standardized questionnaire was developed as antithrombotic questionnaire tool. The pharmacist assessed whether the antithrombotic therapy was correct or potentially incorrect based on answers given by patients and based on the medical record. The primary outcome of the study was the sensitivity and specificity of the antithrombotic questionnaire tool to identify patients with potentially incorrect antithrombotic therapy. RESULTS: For 95 patients, the pharmacist assessed that in 81 (85%) the antithrombotic therapy was correct and in 14 (15%) potentially incorrect. Based on the medical record, 86 patients (91%) were assessed as correct and 9 (9%) as potentially incorrect. The sensitivity of the tool was 100% and the specificity 94%. CONCLUSIONS: This study demonstrated that the antithrombotic questionnaire tool is a suitable tool to assess whether the patient's antithrombotic therapy is potentially incorrect. It can be applied to identify patients with potentially incorrect antithrombotic therapy.

Smaller nadroparin dose reductions required for patients with renal impairment: A multicenter cohort study.

BACKGROUND: Guidelines advise 50 % and 25 % dose reduction of the therapeutic nadroparin dose (86 IU/kg) in patients with eGFR 15-29 and 30-60 ml/min respectively. For monitoring, peak anti-Xa levels are suggested. Data lack whether this results in therapeutic anti-Xa levels or in anti-Xa levels that are comparable to those of patients without renal impairment. AIMS: To determine dose ranges in patients with renal impairment that result in therapeutic anti-Xa levels and to determine the percentage of the 86 IU/kg dose that results in anti-Xa levels normally occurring in patients without renal impairment. METHODS: A retrospective cohort study was conducted in five hospitals. Patients ≥18 years of age, with an eGFR ≥ 15 ml/min were included. The first correctly sampled peak (i.e. 3-5 h after ≥ third administration, regardless of dose per patient) was included. Simulated prediction models were developed using multiple linear regression. RESULTS: 770 patients were included. eGFR and hospital affected the association between dose and anti-Xa level. The doses for peak anti-Xa levels of 0.75 IU/ml differed substantially between hospitals and ranged from 55 to 91, 65-359 and 68-168 IU/kg in eGFR 15-29, 30-60 and > 60 ml/min/1.73m2, respectively. In eGFR 15-29 and 30-60 ml/min/1.73m2, doses of 75 % and 91 % of 86 IU/kg respectively, were needed for anti-Xa levels normally occurring in patients with eGFR > 60 ml/min. CONCLUSION: We advise against anti-Xa based dose-adjustments as long as anti-Xa assays between laboratories are not harmonized and an anti-Xa target range is not validated. A better approach might be to target levels similar to eGFR > 60 ml/min/1.73m2, which are achieved by smaller dose reductions.

Compliance to perioperative anticoagulation protocols in elderly patients undergoing elective orthopedic procedures: a retrospective observational cohort study on 548 patients.

BACKGROUND: Compliance with perioperative anticoagulation guidelines is essential to minimize bleeding and thromboembolic risks in patients undergoing surgery. Compared to vitamin-K antagonists (VKAs), perioperative management of direct oral anticoagulants (DOACs) contains fewer steps. Therefore, we hypothesized that noncompliance with guidelines in VKA users is higher than in DOAC users. The primary aim of our study was to investigate the difference in noncompliance to perioperative anticoagulant management guidelines between elderly patients using VKAs versus those using DOACs. The secondary aim was to determine the difference in occurrence of conflicting information communicated to the patients and the difference in incidence of coagulation-related adverse events. METHODS: This retrospective non-controlled observational cohort study examined elderly patients undergoing elective orthopedic surgery in a teaching hospital in the Netherlands. All patients undergoing elective orthopedic surgery between 1 May 2016 and 1 January 2020, aged 70 years and over, using VKAs or DOACs were selected. Nonelective surgeries were excluded. The primary outcome was the noncompliance to perioperative anticoagulant management guidelines. Secondary outcomes were missing or conflicting information on anticoagulation management communicated to the patient and coagulation-related adverse events. For continuous data, the unpaired T-test was used and for categorical data, the chi-square test. RESULTS: In patients using VKAs, noncompliance to one of the steps of perioperative anticoagulation management was 81%, compared to 55% in patients using DOACs (p < 0.001). In most cases, VKAs or DOACs were interrupted for longer than recommended. In 13% of patients using a VKA with perioperative bridging, bridging was not conducted as recommended in the guidelines. In 13% of patients using a DOAC, a low-molecular-weight heparin (LMWH) was prescribed while a DOAC had already been restarted postoperatively. VKA users received conflicting information about perioperative anticoagulation management more often than DOAC users (33% versus 20%; p < 0.001). No difference was seen in postoperative coagulation-related complications. CONCLUSION: Guidelines compliance in DOAC users is higher than in VKA users. Clinical decision support to help in selecting the right interruption interval in DOAC users, simplified standardized perioperative management, good coordination of instructions given to patients, and familiarity with updated guidelines are important in reducing noncompliance.

Use of xylometazoline in hospitalised infants: is it safe? A retrospective cohort study.

OBJECTIVE: When infants suffer from nasal congestion, xylometazoline spray or drops can be effective to facilitate breathing and drinking. However, case reports on side effects have resulted in international warnings regarding use of xylometazoline in infants. Nevertheless, the incidence of these side effects in hospitalised infants is unknown. DESIGN: Retrospective cohort study. SETTING: Teaching hospital between 2017 and 2021. PATIENTS: Infants under 2 years of age. EXPOSURE: Receiving either saline-only (unlimited frequency, concentration 0.9%) or in combination with xylometazoline (maximum three times daily, concentration 0.025%). MAIN OUTCOME MEASURES: Predefined potential side effects (events), including among others apnoea, nausea, bradycardia, cyanosis and nosebleeds, were extracted from patient records, and the probability to be caused by saline only or xylometazoline-saline was determined using the ADR Probability Scale. RESULTS: We included 898 admitted children during 1285 treatment episodes who received saline with or without xylometazoline. 26 events occurred in the saline-only group (incidence 20.0/100 treatment episodes), and 117 events occurred in the xylometazoline saline group (incidence of 10.5/100 treatment episodes), which was significantly lower (OR 0.47 95% CI 0.29 to 0.75, p=0.002). No definite linked or life-threatening events were found. Three nosebleeds had a probable link to the use of xylometazoline-saline, and all other events could only possibly be linked to saline-only or xylometazoline saline use. The incidence of all events was higher in the saline-only group as compared with the xylometazoline saline group, except nausea, which had a similar occurrence (p=0.65). Results were very similar across (gestational) age groups, gender and reasons for admission. CONCLUSION: The use of low-dose xylometazoline seems to be safe in hospitalised infants.

Discontinuation of infliximab treatment in patients with inflammatory bowel disease who retransitioned to originator and those who remained on biosimilar.

Background: Many patients with inflammatory bowel disease (IBD) have transitioned from an infliximab originator to a biosimilar. However, some patients retransition to the originator (i.e. stop biosimilar and reinitiate the originator). Whether this sign of potential unsatisfactory treatment response is specifically related to the infliximab biosimilar or the patient and/or the disease including patients' beliefs on the biosimilar is unclear. Objectives: We aimed to compare the risk of and reasons for infliximab discontinuation between retransitioned patients and those remaining on biosimilar. Design: Non-interventional, multicentre cohort study. Methods: IBD patients who transitioned from infliximab originator to biosimilar between January 2015 and September 2019 in two Dutch hospitals were eligible for this study. Retransitioned patients (retransitioning cohort) were matched with patients remaining on biosimilar (biosimilar remainder cohort). Reasons for discontinuation were categorised as the unwanted response (i.e. loss of effect or adverse events) or remission. Risk of unwanted discontinuation was compared using Cox proportional hazards models. Results: Patients in the retransitioning cohort (n = 44) were younger (median age 39.9 versus 44.0 years), more often female (65.9% versus 48.9%) and had shorter dosing intervals (median 48.5 versus 56.0 days) than in the biosimilar remainder cohort (n = 127). Infliximab discontinuation due to unwanted response was 22.7% in the retransitioning and 13.4% in the biosimilar remainder cohort, and due to remission was 2.3% and 9.4%, respectively. Retransitioned patients are at increased risk of discontinuing due to unwanted response compared with biosimilar remainder patients (adjusted HR 3.7, 95% CI: 1.0-13.9). Patients who retransitioned due to an increase in objective disease markers had higher discontinuation rates than patients who retransitioned due to symptoms only (66.7% versus 23.7%). Conclusion: Retransitioned patients are at increased risk of infliximab discontinuation due to unwanted response. Retransitioning appeared related to the patient and/or disease and not the product. Clinicians might switch patients opting for retransitioning to other treatment regimens.

Implementation of a Patient Questionnaire in Community Pharmacies to Improve Care for Patients Using Combined Antithrombotic Therapy: A Qualitative Study.

For several indications or combinations of indications the use of more than one antithrombotic agent is required. The duration of combined antithrombotic therapy depends on indication and patient characteristics. This study investigated the use of an antithrombotic questionnaire tool that had been developed for pharmacists to detect patients with possible incorrect combined antithrombotic therapy. The objective of this study was to identify potential barriers and facilitators that could influence the implementation of the developed antithrombotic questionnaire tool in daily community pharmacy practice. A qualitative study was conducted at 10 Dutch community pharmacies in which the antithrombotic questionnaire tool had been used with 82 patients. Semi-structured interviews were conducted with pharmacy staff who used the antithrombotic questionnaire tool. The interview questions to identify barriers and facilitators were based on the Consolidated Framework for Implementation Research. The interview data were analysed using a deductive thematic analysis. Ten staff members from nine different pharmacies were interviewed. Facilitators for implementation were that the questionnaire was easily adaptable and easy to use, as well as the relative short duration to administer the questionnaire. A possible barrier for using the questionnaire was a lower priority for using the questionnaire at moments when the workload was high. The pharmacists estimated that the questionnaire could be used for 70-80% of the patient population and they thought that it was a useful addition to regular medication surveillance. The antithrombotic questionnaire tool can be easily implemented in pharmacy practice. To implement the tool, the focus should be on integrating its use into daily activities. Pharmacists can use this tool in addition to regular medication surveillance to improve medication safety in patients who use combined antithrombotic therapy.

OCT1 polymorphism is associated with response and survival time in anti-Parkinsonian drug users.

Substrates for the Organic Cation Transporter 1, encoded by the SLC22A1 gene, are metformin, amantadine, pramipexole, and, possibly, levodopa. Recently, we identified that the rs622342 A > C polymorphism is associated with the HbA1c lowering effect in metformin users. In the Rotterdam Study, we associated this polymorphism with higher prescribed doses of all anti-Parkinsonian drugs. Between the first and fifth prescriptions for levodopa, for each minor rs622342 C allele, the prescribed doses were 0.34 defined daily dose higher (95% CI 0.064, 0.62; p=0.017). The mortality ratio after start of levodopa therapy was 1.47 times higher (95% CI 1.01, 2.13; p=0.045).

Novel CYP3A4 intron 6 single nucleotide polymorphism is associated with simvastatin-mediated cholesterol reduction in the Rotterdam Study.

OBJECTIVES: CYP3A4 is involved in the oxidative metabolism of many drugs and xenobiotics including the HMG-CoA reductase inhibitor simvastatin. The objective of this study was to investigate whether a new CYP3A4 functional single nucleotide polymorphism (SNP) in intron 6 (CYP3A4*22) modifies the effect of simvastatin on total cholesterol (TOTc) or LDL cholesterol (LDLc) reduction in a population-based cohort study. METHODS: In a total of 80 incident simvastatin users, the association between the CYP3A4 intron 6 C>T SNP (rs35599367) and reduction in cholesterol levels was analyzed using linear regression analysis and adjusting for potential confounding factors. RESULTS: The CYP3A4*22 allele was associated with a trend towards a stronger simvastatin lipid-lowering response, as reflected by the greater reduction in both TOTc and LDLc levels when compared with homozygous wild type. We observed that the CYP3A4*22 allele carriers had an increased reduction in TOTc and LDLc: -0.25 mmol/l (95% confidence interval [CI(95%)]=[-0.52; 0.01], P=0.058) and -0.29 mmol/l (CI(95%)=[-0.58; 0.01], P=0.054) when compared with homozygous CC. When we adjusted the model for potential confounding factors, the corresponding reduction in TOTc was -0.31 mmol/l (CI(95%)=[-0.59;-0.04], P=0.028) and for LDLc -0.34 mmol/l (CI(95%)=[-0.66; -0.02], P=0.034) greater for CYP3A4*22 allele carriers when compared with homozygotes wild type. CONCLUSION: The CYP3A4*22 intron 6 SNP T-variant allele was associated with reduced CYP3A4 activity, resulting in a better lipid lowering response to simvastatin, when data were adjusted for confounding factors. This observation is a step towards the clarification of the reasons of interindividual variability in statins response and may potentially lead to improved tailoring of simvastatin therapy.