Clinical risk management in Dutch community pharmacies: the case of drug-drug interactions

Prevalence of potential drug - drug interactions in the cardiothoracic intensive care unit patients in a Chinese tertiary care teaching hospital

Background

With an increasing number of reviews describing clinically significant drug–drug interactions (DDIs), the scope and severity of interactions involving commonly used drugs in cardiothoracic intensive care units (CCUs) remain unclear. This study aims to identify risk factors and determine the incidence of potential DDIs in intensive care units.

Methods

DDIs were identified based on the profile of the prescribed drug and classified according to the Micromedex drug interaction database. Potential risk factors associated with DDIs have been identified.

Results

A total of 3193 medication episodes were evaluated, and 680 DDIs (21.3%) were found. A total of 203 patients were recruited into the study, with an average of 3.4 DDIs per patient [95% confidence interval (3.2 − 3.6)]. A total of 84.2% of the patients experienced at least one DDI. Anticoagulant and antiplatelet agents were involved in 33.5% (228/680) of the potential drug − drug interactions in the CCU. Univariate analysis and multiple logistic regression analysis showed that the age of the patient and the number of medications prescribed were significantly correlated with the occurrence of DDIs. In multiple linear regression analysis, the number of DDIs had a significant correlation only with the number of prescription drugs.

Conclusions

A high prevalence of DDIs was observed, especially in intensive care units without pharmacist intervention and computerized drug monitoring systems, highlighting the need for active surveillance to prevent potential adverse events.

Investigating Potential Drug-Drug Interactions from Greek e-Prescription Data

BACKGROUND

The prevalence of potential drug-drug interactions (pDDIs) is indicative of the prevalence of actual drug-drug interactions and prescription quality. However, they are significantly understudied in Greece.

OBJECTIVE

To determine the prevalence of pDDIs among outpatients and identify factors associated with their occurrence.

METHODS

Anonymous e-prescription data between 2012 and 2017 were obtained from community pharmacies in Thessaloniki, Greece. Patients taking more than one medication for at least three months were included. pDDIs were identified and categorized depending on their clinical significance using Drug Interactions Checker. Crude and adjusted odds ratios (ORs) with accompanying 95% confidence intervals (CIs) of risk factors of pDDIs occurrence were identified using multivariable logistic regression.

RESULTS

During the study period, 6,000 anonymous e-prescriptions (1,000 per year) satisfying the inclusion criteria, were collected. The overall prevalence of major pDDIs was 17.4% (63.0% for moderate pDDIs). The most common major pDDIs were between amlodipine and simvastatin (22.8% of major interactions) followed by clopidogrel and omeprazole (6.4% of major interactions). Polypharmacy (≥5 concomitantly received medications) was associated with an increased risk of major pDDIs (adjusted OR, 5.72; 95% CI, 4.87-6.72); no associations were observed regarding age, sex and number of prescribing physicians.

CONCLUSION

The prevalence of pDDIs in this study was higher than previously reported in other European countries, with polypharmacy being a potential risk factor. Those results argue for a need for improvement in the area of prescribing in Greece.

The use of a clinical decision support tool to assess the risk of QT drug-drug interactions in community pharmacies

Introduction:

The handling of drug–drug interactions regarding QTc-prolongation (QT-DDIs) is not well defined. A clinical decision support (CDS) tool will support risk management of QT-DDIs. Therefore, we studied the effect of a CDS tool on the proportion of QT-DDIs for which an intervention was considered by pharmacists.

Methods:

An intervention study was performed using a pre- and post-design in 20 community pharmacies in The Netherlands. All QT-DDIs that occurred during a before- and after-period of three months were included. The impact of the use of a CDS tool to support the handling of QT-DDIs was studied. For each QT-DDI, handling of the QT-DDI and patient characteristics were extracted from the pharmacy information system. Primary outcome was the proportion of QT-DDIs with an intervention. Secondary outcomes were the type of interventions and the time associated with handling QT-DDIs. Logistic regression analysis was used to analyse the primary outcome.

Results:

Two hundred and forty-four QT-DDIs pre-CDS tool and 157 QT-DDIs post-CDS tool were included. Pharmacists intervened in 43.0% and 35.7% of the QT-DDIs pre- and post-CDS tool respectively (odds ratio 0.74; 95% confidence interval 0.49–1.11). Substitution of interacting agents was the most frequent intervention. Pharmacists spent 20.8 ± 3.5 min (mean ± SD) on handling QT-DDIs pre-CDS tool, which was reduced to 14.9 ± 2.4 min (mean ± SD) post-CDS tool. Of these, 4.5 ± 0.7 min (mean ± SD) were spent on the CDS tool.

Conclusion:

The CDS tool might be a first step to developing a tool to manage QT-DDIs via a structured approach. Improvement of the tool is needed in order to increase its diagnostic value and reduce redundant QT-DDI alerts.

Plain Language Summary

The use of a tool to support the handling of QTc-prolonging drug interactions in community pharmacies

Introduction: Several drugs have the ability to cause heart rhythm disturbances as a rare side effect. This rhythm disturbance is called QTc-interval prolongation. It may result in cardiac arrest. For health care professionals, such as physicians and pharmacists, it is difficult to decide whether or not it is safe to proceed treating a patient with combinations of two or more of these QT-prolonging drugs. Recently, a tool was developed that supports the risk management of these QT drug–drug interactions (QT-DDIs).

Methods: In this study, we studied the effect of this tool on the proportion of QT-DDIs for which an intervention was considered by pharmacists. An intervention study was performed using a pre- and post-design in 20 community pharmacies in The Netherlands. All QT-DDIs that occurred during a before- and after-period of 3 months were included.

Results: Two hundred and forty-four QT-DDIs pre-implementation of the tool and 157 QT-DDIs post-implementation of the tool were included. Pharmacists intervened in 43.0% of the QT-DDIs before the tool was implemented and in 35.7% after implementation of the tool. Substitution of one of the interacting agents was the most frequent intervention. Pharmacists spent less time on handling QT-DDIs when the tool was used.

Conclusion: The clinical decision support tool might be a first step to developing a tool to manage QT-DDIs via a structured approach.

Identifying and Characterizing Serious Adverse Drug Reactions Associated With Drug-Drug Interactions in a Spontaneous Reporting Database

Background: Drug-drug interactions (DDIs) are an important cause of adverse drug reactions (ADRs). In literature most of studies focus only on potential DDIs, while detailed data on serious ADRs associated with DDIs are limited. Our aim is to identify and characterize serious ADRs caused by DDIs using a spontaneous reporting database.

Methods: All serious ADR reports, not related to vaccines and with a “definite”, “probable” or “possible” causality assessment, inserted into the National Pharmacovigilance database from Veneto Region (January 1, 2015 to May 31, 2020) were analyzed. A list of drug pairs was created by selecting the reports containing at least two suspected or concomitant drugs. We verified which drug pairs potentially interacted according to the online version of DRUGDEX^® system. For each potential DDI we controlled whether the ADR description in the report corresponded to the interaction effect as described in Micromedex. A detailed characterization of all serious reports containing an occurring DDI was performed.

Results: In the study period a total of 31,604 reports of suspected ADRs from the Veneto Region were identified, of which 2,195 serious reports (6.9% of all ADR reports) containing at least two suspected or concomitant drugs were analyzed. We identified 1,208 ADR reports with at least one potential DDI (55.0% of 2,195) and 381 reports (17.4% of 2,195 reports) with an occurring ADR associated with a DDI. The median age of patients and the number of contraindicated or major DDIs were significantly higher in reports with an occurring DDI. Warfarin was the most frequently reported interacting drug and the most common ADRs were gastrointestinal or cerebral hemorrhagic events. The proton pump inhibitors/warfarin, followed by platelet aggregation inhibitors/warfarin were the drug-drug combinations most frequently involved in ADRs caused by DDIs. The highest proportion of fatal reports was observed with platelet aggregation inhibitors/warfarin and antidepressants/warfarin.

Conclusion: Our findings showed that about one-third of patients exposed to a potential DDI actually experienced a serious ADR. Furthermore, our study confirms that a spontaneous reporting database could be a valuable resource for identifying and characterizing ADRs caused by DDIs and the drugs leading to serious ADRs and deaths.

Discontinuation and dose adjustment of metoprolol after metoprolol-paroxetine/fluoxetine co-prescription in Dutch elderly

Purpose

Co‐prescription of paroxetine/fluoxetine (a strong CYP2D6 inhibitor) in metoprolol (a CYP2D6 substrate) users is common, but data on the clinical consequences of this drug‐drug interaction are limited and inconclusive. Therefore, we assessed the effect of paroxetine/fluoxetine initiation on the existing treatment with metoprolol on the discontinuation and dose adjustment of metoprolol among elderly.

Methods

We performed a cohort study using the University of Groningen IADB.nl prescription database (www.IADB.nl). We selected all elderly (≥60 years) who had ever been prescribed metoprolol and had a first co‐prescription of paroxetine/fluoxetine, citalopram (weak CYP2D6 inhibitor), or mirtazapine (negative control) from 1994 to 2015. The exposure group was metoprolol and paroxetine/fluoxetine co‐prescription, and the other groups acted as controls. The outcomes were early discontinuation and dose adjustment of metoprolol. Logistic regression was applied to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI).

Results

Combinations of metoprolol‐paroxetine/fluoxetine, metoprolol‐citalopram, and metoprolol‐mirtazapine were started in 528, 673, and 625 patients, respectively. Compared with metoprolol‐citalopram, metoprolol‐paroxetine/fluoxetine was not significantly associated with the early discontinuation and dose adjustment of metoprolol (OR = 1.07, 95% CI:0.77‐1.48; OR = 0.87, 95% CI:0.57‐1.33, respectively). In comparison with metoprolol‐mirtazapine, metoprolol‐paroxetine/fluoxetine was associated with a significant 43% relative increase in early discontinuation of metoprolol (OR = 1.43, 95% CI:1.01‐2.02) but no difference in the risk of dose adjustment. Stratified analysis by gender showed that women have a significantly high risk of metoprolol early discontinuation (OR = 1.62, 95% CI:1.03‐2.53).

Conclusion

Paroxetine/fluoxetine initiation in metoprolol prescriptions, especially for female older patients, is associated with the risk of early discontinuation of metoprolol.

Clinical Decision Support and Optional Point of Care Testing of Renal Function for Safe Use of Antibiotics in Elderly Patients: A Retrospective Study in Community Pharmacy Practice

Objective

The aim was to investigate the management of drug therapy alerts on safe use of antibiotics in elderly patients with (potential) renal impairment and the contribution of optional creatinine point of care testing (PoCT) in community pharmacy practice.

Methods

Community pharmacists used a clinical decision support system (CDSS) for seven antibiotics. Alerts were generated during prescription processing in the case of previously registered renal impairment and when no information on renal function was available for patients aged 70 and over. Pharmacists could perform PoCT when renal function could not be retrieved from other health care professionals. Actions were registered in the CDSS. A retrospective descriptive analysis of alert management, performed PoCT and medication dispensing histories was performed.

Results

A total of 351 pharmacists registered the management of 88,391 alerts for 64,763 patients. For 68,721 alerts (77.7%), the pharmacist retrieved a renal function above the threshold for intervention. 1.7% of the alerts (n = 1532) led to a prescription modification because of renal impairment; in 3.0% of the alerts (n = 2631), the patient had renal impairment, but the pharmacist judged that no intervention was needed. Pharmacists performed 1988 PoCTs (2.2% of the alerts), which led to 15 prescription modifications (0.8% of the PoCT).

Conclusion

Community pharmacists performed CDSS-based interventions to prevent potentially inappropriate (dosing of) antibiotics in elderly patients with renal impairment. Pharmacists were well able to retrieve information on renal function, using PoCT in a limited number of cases. The intervention rate could be greatly increased by better registration of information on renal function. Performing PoCT seems especially worthwhile in the highest age groups.

Better specification of triggers to reduce the number of drug interaction alerts in primary care

OBJECTIVE

Drug interaction alerts (drug-drug and drug-disease interaction alerts) for chronic medications substantially contribute to alert fatigue in primary care. The aim of this study was to determine which events require (re)assessment of a drug interaction and whether using these events as triggers in clinical decision support systems (CDSSs) would affect the alert rate.

METHODS

Two random 5% data samples from the CDSSs of 123 community pharmacies were used: dataset 1 and 2. The top 10 of most frequent drug interaction alerts not involving laboratory values were selected. To reach consensus on events that should trigger alerts (e.g. first time dispensing, dose modification) for these drug interactions, a two-step consensus process was used. An expert panel of community pharmacists participated in an online survey and a subsequent consensus meeting. A CDSS with alerts based on the consensus was simulated in both datasets.

RESULTS

Dataset 1 and 2 together contained 1,672,169 prescriptions which led to 591,073 alerts. Consensus on events requiring alerts was reached for the ten selected drug interactions. The simulation showed a reduction of the alert rate of 93.0% for the ten selected drug interactions (comparable for dataset 1 and 2), corresponding with a 28.3% decrease of the overall drug interaction alert rate.

CONCLUSION

By consensus-based better specification of the events that trigger drug interaction alerts in primary care, the alert rate for these drug interactions was reduced by over 90%. This promising approach deserves further investigation to assess its consequences and applicability in daily practice.

Lower alert rates by clustering of related drug interaction alerts

OBJECTIVE

We aimed to investigate to what extent clustering of related drug interaction alerts (drug-drug and drug-disease interaction alerts) would decrease the alert rate in clinical decision support systems (CDSSs).

METHODS

We conducted a retrospective analysis of drug interaction alerts generated by CDSSs in community pharmacies. Frequently generated combinations of alerts were analyzed for associations in a 5% random data sample (dataset 1). Alert combinations with similar management recommendations were defined as clusters. The alert rate was assessed by simulating a CDSS generating 1 alert per cluster per patient instead of separate alerts. The simulation was performed in dataset 1 and replicated in another 5% data sample (dataset 2).

RESULTS

Data were extracted from the CDSSs of 123 community pharmacies. Dataset 1 consisted of 841 572 dispensed prescriptions and 298 261 drug interaction alerts. Dataset 2 was comparable. Twenty-two frequently occurring alert combinations were identified. Analysis of these associated alert combinations for similar management recommendations resulted in 3 clusters (related to renal function, electrolytes, diabetes, and cardiovascular diseases). Using the clusters in alert generation reduced the alert rate within these clusters by 53-70%. The overall number of drug interaction alerts was reduced by 11% in dataset 1 and by 12% in dataset 2. This corresponds to a decrease of 21 alerts per pharmacy per day.

DISCUSSION AND CONCLUSION

Using clusters of drug interaction alerts with similar management recommendations in CDSSs can substantially decrease the overall alert rate. Further research is needed to establish the applicability of this concept in daily practice.

Nature and management of duplicate medication alerts

OBJECTIVE

To investigate the nature of duplicate medication (DM) alerts, their management by community pharmacists, and potential characteristics of DM alerts that lead to interventions by pharmacists.

METHODS

Observational study in 53 community pharmacies. Each pharmacist registered the nature and management of 24 DM alerts on a structured form.

RESULTS

On average, the clinical decision support systems generated 20.4 DM alerts per 100 dispensed drugs. In half of the 1272 registered alerts, the pharmacists judged that there was no risk for concurrent use of both prescriptions. In 32% of the alerts, the DM alert was generated for an intentional combination. In 17% of the alerts, there was a risk for unintentional concurrent use. In 32% of the alerts the pharmacists decided that one or more actions were needed: the electronic patient record was updated in 15% of the alerts and in 19% of the alerts the pharmacists performed an external action-for example, informing the patient or modifying the prescription (including 5 therapeutic prescription modifications and 22 logistic prescription modifications). Alerts concerning first dispensing were more likely to be followed by an external action than alerts concerning refills (40% vs 14%, P < .001).

DISCUSSION AND CONCLUSION

In community pharmacy, prescription modifications based on DM alerts are rare, but DM alerts lead with some regularity to other actions-for example, patient instruction and update of the electronic patient record. As the current DM alerts are diverse and nonspecific in detecting situations where external action is considered relevant, other ways of alerting should therefore be considered.

Assessing the safety features of electronic patient medication record systems used in community pharmacies in England

Aims

To evaluate the ability of electronic patient medication record (ePMR) systems used in community pharmacies in England to detect and alert users about clinical hazards, errors and other safety problems.

Methods

Between September 2012 and November 2012, direct on-site observational data about the performance of ePMR systems were collected from nine sites. Twenty-eight scenarios were developed by consensus agreement between a general practitioner and two community pharmacists. Each scenario was entered into the ePMR system, and the results obtained from the assessment of six unique systems in nine sites, in terms of the presence or absence of an alert, were recorded onto a prespecified form.

Results

None of the systems produced the correct responses for all of the 28 scenarios tested. Only two systems provided an alert to penicillin sensitivity. No dose or frequency check was observed when processing a prescription for methotrexate. One system did not warn about nonsuitability of aspirin prescribed to a child of 14 years of age. In another system, it was not possible to record a patient's pregnancy status. None of the six systems provided any warning for diclofenac overdose, high initiation dose of morphine sulfate or significant dose increase. Only one of the systems did not produce any spurious alerts.

Conclusions

The performance of the ePMR systems tested was variable and suboptimal. The findings suggest the need for minimum specifications and standards for ePMR systems to ensure consistency of performance.

Prevalence and Correlates of Drug-drug Interactions in the Regional Hospital of Gjilan, Kosovo

AIM

Our aim was to assess the prevalence and socioeconomic and clinical correlates of drug-drug interactions among the adult population of transitional Kosovo.

METHODS

A cross-sectional study was conducted including a representative sample of 1921 patients aged ≥18 years (mean age: 57.8±11.2 years; 50.3% women; overall response: 96%) from the regional hospital of Gjilan, Kosovo, during 2011-2013. Potential drug-drug-interactions were assessed and clinical data as well as demographic and socioeconomic information were collected. Binary logistic regression was used to assess the correlates of drug-drug interactions.

RESULTS

Upon multivariable adjustment for all the demographic and socioeconomic factors as well as the clinical characteristics, drug-drug interactions were positively and significantly related to older age (OR=2.1, 95%CI=1.3-2.8), a lower educational attainment (OR=1.4, 95%CI=1.1-1.9), a longer hospitalization period (OR=2.7, 95%CI=2.1-3.6), presence of three groups of diseases [infectious diseases (OR=1.7, 95%CI=1.3-2.4), cardiovascular diseases (OR=1.8, 95%CI=1.4-2.6), respiratory diseases (OR=1.6, 95%CI=1.2-2.5)], presence of comorbid conditions (OR=3.2, 95%CI=2.3-4.4) and an intake of at least four drugs (OR=5.9, 95%CI=4.6-7.1).

CONCLUSIONS

Our study provides important evidence on the prevalence and socioeconomic and clinical correlates of drug-drug interactions among the hospitalized patients in the regional hospital of Gjilan, Kosovo. Findings from our study should raise the awareness of decision-makers and policy makers about the prevalence and determinants of drug-drug interactions in the adult population of post-war Kosovo.

What, if all alerts were specific - estimating the potential impact on drug interaction alert burden

PURPOSE

Clinical decision support systems (CDSS) may potentially improve prescribing quality, but are subject to poor user acceptance. Reasons for alert overriding have been identified and counterstrategies have been suggested; however, poor alert specificity, a prominent reason of alert overriding, has not been well addressed. This paper aims at structuring modulators that determine alert specificity and estimating their quantitative impact on alert burden.

METHODS

We developed and summarized optimizing strategies to guarantee the specificity of alerts and applied them to a set of 100 critical and frequent drug interaction (DDI) alerts. Hence, DDI alerts were classified as dynamic, i.e. potentially sensitive to prescription-, co-medication-, or patient-related factors that would change alert severity or render the alert inappropriate compared to static, i.e. always applicable alerts not modulated by cofactors.

RESULTS

Within the subset of 100 critical DDI alerts, only 10 alerts were considered as static and for 7 alerts, relevant factors are not generally available in today's patient charts or their consideration would not impact alert severity. The vast majority, i.e. 83 alerts, might require a decrease in alert severity due to factors related to the prescription (N=13), the co-medication (N=11), individual patient data (N=36), or combinations of them (N=23). Patient-related factors consisted mainly of three lab values, i.e. renal function, potassium, and therapeutic drug monitoring results.

CONCLUSION

This paper outlines how promising the refinement of knowledge bases is in order to increase specificity and decrease alert burden and suggests how to structure knowledge bases to refine DDI alerting.

Epidemiology and characteristics of adverse drug reactions caused by drug-drug interactions

INTRODUCTION

Drug-drug interactions (DDIs) arise in numerous different ways, involving pharmacokinetic or pharmacodynamic mechanisms. Adverse drug reactions are a possible consequence of DDIs and health operators are often unaware of the clinical risks of certain drug combinations. Many papers on drug interactions have been published in recent years, but most of them focused on potential DDIs while few studies have been conducted on actual interactions.

AREAS COVERED

This paper reviews the epidemiology of actual DDIs in outpatients as well as in hospital settings and in spontaneous reporting databases. The incidence of actual DDIs is consistently lower than that of potential DDIs. However, the absolute number of patients involved is high, representing a significant proportion of adverse drug reactions. The importance of risk factors such as age, polypharmacy and genetic polymorphisms is also evaluated. The relevance and efficacy of tools for recognizing and preventing DDIs are discussed.

EXPERT OPINION

Potential DDIs far outnumber actual drug interactions. The potential for an adverse interaction to occur is often theoretical, and clinically important adverse effects occur only in the presence of specific risk factors. Several studies have shown the efficacy of computers in early detection of DDIs. However, a correct risk-benefit evaluation by the prescribing physician, together with a careful clinical, physiological and biochemical monitoring of patients, is essential. Future directions of drug interaction research include the increasing importance of pharmacogenetics in preventing DDIs and the evaluation of interactions with biological drugs.

Clarity and applicability of drug-drug interaction management guidelines: a systematic appraisal by general practitioners and community pharmacists in the Netherlands

BACKGROUND

Despite the availability and daily use of computerized drug-drug interaction surveillance systems, exposure to potentially relevant drug-drug interactions (DDIs) continues. DDI management guidelines are often inadequate and clear management options are lacking, which attributes to overriding of DDI signals. Although general criteria for the development and reporting of high-quality clinical practice guidelines have been identified, it appears these have not yet been applied to DDI management guidelines.

OBJECTIVES

The aim of the study was to assess the clarity and applicability of guidelines for the management of potentially harmful DDIs.

METHODS

We selected 13 DDIs that are potentially harmful for patients and frequently occur in community pharmacy practice in the Netherlands. The clarity and applicability of the management guidelines of these DDIs were appraised using the appropriate two domains - 'Clarity and presentation' and 'Applicability', of the validated Appraisal of Guidelines for Research and Evaluation (AGREE) Instrument. The appraisal was performed by 12 community pharmacists and 12 general practitioners. The standardized domain scores and mean item scores for 'Clarity and presentation' and 'Applicability' were compared.

RESULTS

All DDI management guidelines were generally found to score well on 'Clarity and presentation', but poorly with respect to 'Applicability' (standardized domain scores 68.0 vs 26.1%). Within the domain 'Clarity and presentation', the item 'tools for application' received the lowest scores. Within the domain 'Applicability', cost implications, organizational barriers and key review criteria were all poorly documented. All guidelines presented non-directive advice using words such as 'consider' and 'regularly'.

CONCLUSIONS

Developers of DDI management guidelines should take the appropriate domains of the AGREE Instrument into consideration in their development processes. The applicability of DDI management guidelines should be pretested before publishing. To improve guideline quality, more attention should particularly be paid to the available tools for applications and cost implications.

Drug use in pregnancy: Knowledge of drug dispensers and pregnant women in Dar es Salaam, Tanzania

More than 90% of pregnant women take prescription or non-prescription drugs at some time during pregnancy. In general, unless absolutely necessary, drugs should not be used during pregnancy because many of them are harmful to the fetus. Appropriate dispensing is one of the steps for rational drug use; so, it is necessary that drug dispensers should have relevant and updated knowledge and skills regarding drug use in pregnancy. To assess the knowledge of drug dispensers and pregnant women regarding drug use in pregnancy, focusing on four commonly used drugs that are teratogenic or cause unwanted effects to the fetus and babies. The study was conducted in two parts: consumers′ perception and providers′ practice. It was a cross-sectional study involving visits to 200 private retail community pharmacies (as simulated client) within Temeke, Ilala and Kinondoni municipals in Dar es Salaam, Tanzania. The second part of the study was conducted at the antenatal clinics of the three municipal hospitals in Dar es Salaam. A semi-structured questionnaire was used to gather information from pregnant women. In total, 200 pregnant women were interviewed. Out of 200 drug dispensers, 86 (43%) were willing to dispense artemether-lumefantrine (regardless of the age of pregnancy), 56 (29%) were willing to dispense sodium valproate, 104 (52%) were willing to dispense captopril and 50 (25%) were willing to dispense tetracycline. One hundred and thirty-three (66.5%) pregnant women reported that they hesitated to take medications without consulting their physicians, 47 (23.5%) indicated that it was safe to take medications during pregnancy, while 123 (61.5%) mentioned that it was best to consult a doctor, while 30 (15%) did not have any preference. Sixty-three (31.5%) women reported that they were aware of certain drugs that are contraindicated during pregnancy. It is evident that most drug dispensers have low knowledge regarding the harmful effects of drugs during pregnancy. Drug dispensing personnel should be considered part of the therapeutic chain and, if appropriately trained, they will play a very important role in promoting rational use of medicines.

Frequency of laboratory measurement and hyperkalaemia in hospitalised patients using serum potassium concentration increasing drugs

PURPOSE

Although, drug-drug interactions (DDIs) between potassium-increasing drugs (PIDs) are known risk factors for developing hyperkalaemia, not much is known about their risk and management strategies during hospitalisation. This study examines the frequency of serum potassium measurements and hyperkalaemia in hospitalised patients, based on the use of one or more PIDs, and the determinants thereof.

METHODS

Adult patients hospitalised in the University Medical Centre Utrecht between 2006 and 2008 were included in this cross-sectional study. The frequency of serum potassium measurements and of hyperkalaemia were compared between patients using only one PID at a time (monotherapy group) and patients using two or more PIDs concomitantly (interaction group). The determinants studied were renal failure, diabetes mellitus, use of diuretics, type of DDI, start of the PIDs within the hospital versus continued home medication and medical speciality.

RESULTS

Serum potassium was measured more frequently in the interaction group than in the monotherapy group [67 vs. 56%; relative risk (RR) 1.19, 95% confidence interval (CI) 1.14-1.24] and the risk of hyperkalaemia was also increased in the interaction group (9.9 vs. 5.9%, RR 1.7, 95% CI 1.3-2.1). The combination of potassium-sparing diuretics plus a potassium supplement, start of the PID within the hospital and hospitalisation in non-internal medicine departments was associated with higher relative risk estimates for hyperkalaemia.

CONCLUSIONS

Among our patient cohort, even when physicians received a direct pop-up to monitor serum potassium levels when prescribing two PIDs concomitantly, serum potassium levels were not measured in 33% of patients, and 10% of patients developed hyperkalaemia. Improved management strategies and/or clinical decision-support systems are needed to decrease the frequency of hyperkalaemia following DDIs.

Frequency and nature of drug-drug interactions in a Dutch university hospital

AIM

Drug-drug interactions (DDIs) may lead to often preventable adverse drug events and health damage. Especially within hospitals, this might be an important factor, as patients are severely ill and multiple medications may be prescribed simultaneously. The objective of this study was to measure the frequency and nature of DDI alerts in a Dutch university hospital.

METHODS

All patients hospitalized in the University Medical Centre Utrecht in 2006 who were prescribed at least one medication were included. The frequency of DDIs was calculated as: (i) the percentage of patients experiencing at least one DDI, and (ii) the percentage of prescriptions generating a DDI alert. Based on the national professional guideline, DDIs were classified into categories of potential clinical outcome, management advice, clinical relevance (A-F) and available evidence (0-4).

RESULTS

Of the 21 277 admissions included, 5909 (27.8%) encountered at least one DDI. Overall, the prescribing physician received a DDI alert in 9.6% of all prescriptions. The most frequently occurring potential clinical consequence of the DDIs was an increased risk of side-effects such as increased bleeding risk (22.0%), hypotension (14.9%), nephrotoxicity (12.6%) and electrolyte disturbances (10.5%). Almost half (48.6%) of the DDIs could be managed by monitoring laboratory values.

CONCLUSIONS

Computerized DDI alerts may be a useful tool to prevent adverse drug events within hospitals, but they may also result in 'alert fatigue'. The specificity of alerts could significantly improve by the use of more sophisticated clinical decision support systems taking into account, for example, laboratory values.

Client and pharmacist factors affecting practice in the management of upper respiratory tract infection presented in community pharmacies: a simulated client study

Objectives

To assess the quality of care provided by community pharmacists for simulated clients (SCs) with upper respiratory tract infection (URI) and to examine the effects of gender and appearance of socioeconomic status (SES) of the SCs on the practice.

Setting

Thirty-two community pharmacies in the south of Thailand with four male and four female SCs.

Method

Each SC visited eight community pharmacies twice, 1month apart, once with moderate and once with an appearance of low SES, in random order. Key outcome variables were history-taking, advice-giving, and antibiotic-dispensing, based on international guidelines. Descriptive statistics and mixed-effects models with nesting of SCs and community pharmacies were conducted.

Key findings

The mean scores for history-taking and advice-giving were low. The proportions of 128 encounters ending up with antibiotics, corticosteroids and nonsteroidal anti-inflammatory drugs were 87.5, 12.5 and 7.8%, respectively. Pharmacist practice did not differ by SC gender or appearance of SES.

Conclusion

Such practice by pharmacists needs improvement. Further studies to confirm the lack of effect of clients' gender and SES are needed.

Documentation Quality in Community Pharmacy: Completeness of Electronic Patient Records After Patients' First Visits

Background:

When patients visit a community pharmacy for the first time, the creation of an electronic patient record (EPR) with relevant and up-to-date data is a prerequisite for adequate medication surveillance and patient counseling.

Objective:

To investigate the level of completeness of documentation in the EPR after a patient's first visit to a Dutch community pharmacy.

Methods:

In each participating pharmacy, newly enlisted (<3 mo) patients to whom at least one medication had been dispensed were enrolled in this survey. For each patient who could be interviewed, pharmacy master students used a structured questionnaire to gather relevant, mandatory patient data (ie, basic characteristics, current drugs used, diseases, intolerabilities, specific conditions) and nonmandatory patient data (eg, diagnostic and monitoring data, personal experiences and habits, drug use problems) from the patient's EPR and from a structured telephone interview with the patient. Data retrieved from the patient's EPR were compared with data provided by the patient during the telephone interview.

Results:

Of 403 selected patients, 154 (38.2%) could be interviewed by telephone. Poor documentation of telephone numbers in the EPR was the main reason for nonresponse (134/249). Interviewers found that 67.7% of prescription drugs, 0% of over-the-counter drugs, 19.6% of diseases, 3.7% of intolerabilities, and none of the specific conditions reported by patients had been documented in the EPR. Nonmandatory data (personal experiences and habits, drug use problems) reported during the patient interview had not been documented in the EPR.

Conclusions:

The EPR after a patient's first visit to the community pharmacy is often incomplete. For new patients, the pharmacist should more proactively and systematically gather patient information, and all relevant information should be recorded, preferably in coded form, in the pharmacy information system to allow more adequate clinical risk management.

Use of anti-depressants and the risk of fracture of the hip or femur

SUMMARY

Anti-depressants are used largely, but have serious side effects. We show that both selective serotonin re-uptake inhibitors (SSRIs) and tricyclic anti-depressants (TCAs) increase the risk of hip/femur fracture and that this risk is time related and depends on the degree of serotonin transporter inhibition. This should be considered when prescribing anti-depressants to patients.

INTRODUCTION

Anti-depressants are known to have serious side effects. We examined the association between the use of anti-depressants and the risk of hip/femur fractures with a special focus on the relation with the degree of 5-hydroxytryptamine transporter (5-HTT) inhibition and the duration of use.

METHODS

A case-control study was conducted within the Dutch PHARMO-RLS database. Cases (n = 6,763) were adult patients with a first hip/femur fracture during the study period. For each case, four controls (n = 26341) were matched by age, gender and geographic region.

RESULTS

The risk of hip/femur fracture increased with current use of SSRIs (adjusted odds ratio (OR(adj)) 2.35 [95% confidence interval (CI) 1.94-2.84]) and TCAs (ORadj 1.76 [95% CI 1.45-2.15]). The risk of hip/femur fracture declined rapidly after discontinuation of use. The risk of hip/femur fracture increased as the degree of 5-HTT inhibition of all anti-depressants increased from OR(adj) 1.64 [95% CI 1.14-2.35] for drugs with low 5-HTT inhibition to OR(adj) 2.31 [95% CI 1.94-2.76] for those with high 5-HTT inhibiting properties.

CONCLUSION

Current use of both SSRIs and TCAs increase hip/femur fracture risk. Further studies are needed to elucidate the mechanistic pathways and the relation with the underlying pathophysiology. Until then, the elevated fracture risk should be considered when prescribing anti-depressants.

Drug-drug interactions in a geriatric outpatient cohort: prevalence and relevance

BACKGROUND

The prevalence of drug-drug interactions (DDIs) in a geriatric population may be high because of polypharmacy. However, wide variance in the clinical relevance of these interactions has been shown.

OBJECTIVES

To explore whether adverse drug reactions (ADRs) as a result of DDIs can be identified by clinical evaluation, to describe the prevalence of ADRs and diminished drug effectiveness as a result of DDIs and to verify whether the top ten most frequent potential DDIs known to public pharmacies are of primary importance in geriatric outpatients in the Netherlands.

METHOD

All adverse events classified by the Naranjo algorithm as being a possible ADR and drug combinations resulting in diminished drug effectiveness were identified prospectively in 807 geriatric outpatients (mean age 81 years) at their first visit. The setting was a diagnostic day clinic. The Medication Appropriateness Index (MAI) and Beers criteria were used to evaluate drug use and identify possible DDIs. The ten most frequent potential interactions, according to a 1997 national database of public pharmacies ('Top Ten') in the Netherlands, and possible adverse events as a result of other interactions, were described. The effects of changes in medication regimen were recorded by checking the medical records.

RESULTS

In 300 patients (44.5% of the 674 patients taking more than one drug), 398 potential DDIs were identified. In 172 (25.5%) of patients taking more than one drug, drug combinations were identified that were responsible for at least one ADR or which possibly resulted in reduced effectiveness of therapy. Eighty-four of the 158 possible ADRs resulting from enhanced action of drugs forming combinations listed in the 'Top Ten' were seen in 73 patients. Only four DDIs resulting in less effective therapy that involved drug combinations in the 'Top Ten' were identified. Changes in drug regimens pertaining to possible interactions were proposed or put into effect in 111 of the 172 (65%) patients with possible DDIs. Sixty-one (55%) of these patients returned for follow-up. Of these, 49 (80%) were shown to have improved after changes were made to their medication regimen.

CONCLUSION

In this study, nearly half of the geriatric outpatients attending a diagnostic day clinic who were taking more than one drug were candidates for DDIs. One-quarter of these patients were found to have possible adverse events or diminished treatment effectiveness that may have been at least partly caused by these DDIs. These potential interactions can be identified through clinical evaluation. In the majority of patients (99 of 172) the potential interactions resulting in possible ADRs or diminished effectiveness were not present in the 'Top Ten' interactions described by a national database of public pharmacies, a finding that emphasizes that the particular characteristics of geriatric patients (e.g. frequent psychiatric co-morbidities) need to be considered when evaluating their drug use. At least 7% of all patients taking more than one drug, and 80% of those with possible drug interactions whose drug regimen was adjusted, benefited from changes made to their drug regimens.

Turning off frequently overridden drug alerts: limited opportunities for doing it safely

OBJECTIVES

This study sought to identify opportunities to safely turn off frequently overridden drug-drug interaction alerts (DDIs) in computerized physician order entry (CPOE).

DESIGN

Quantitative retrospective analysis of drug safety alerts overridden during 1 month and qualitative interviews with 24 respondents (18 physicians and 6 pharmacists) about turning off frequently overridden DDI alerts, based on the Dutch drug database, in a hospital setting. Screen shots and complete texts of frequently overridden DDIs were presented to physicians of internal medicine, cardiology, and surgery and to hospital pharmacists who were asked whether these could be turned off hospital-wide without impairing patient safety, and the reasons for their recommendations.

RESULTS

Data on the frequency of alerts overridden in 1 month identified 3,089 overrides, of which 1,963 were DDIs. The category DDIs showed 86 different alerts, of which 24 frequently overridden alerts, accounting for 72% of all DDI overrides, were selected for further evaluation. The 24 respondents together made 576 assessments. Upon investigation, differences in the reasons for turning off alerts were found across medical specialties and among respondents within a specialty. Frequently mentioned reasons for turning off were "alert well known," "alert not serious," or "alert not needing (additional) action," or that the effects of the combination were monitored or intended. For none of the alerts did all respondents agree that it could be safely turned off hospital-wide. The highest agreement was 13 of 24 respondents (54%). A positive correlation was found between the number of alerts overridden and the number of clinicians recommending to turn them off.

CONCLUSION

Although the Dutch drug database is already a selected reduction from all DDIs mentioned in literature, the majority of respondents wanted to turn off DDI alerts to reduce alert overload. Turning off DDI alerts hospital-wide appeared to be problematic because of differences among physicians regarding drug-related knowledge and of differences across the hospital in routine drug monitoring practices. Furthermore, several reasons for suppression of alerts could be questioned from a safety perspective. Further research should investigate when each of the following might help: changes in alert texts; new differential alert triggers based on clinician knowledge or specialty; and nonintrusive alert presentation so long as serum levels and patient parameters are measured and stay within limits.

A composite screening tool for medication reviews of outpatients: general issues with specific examples

Regular performance of medication reviews is prominent among methods that have been advocated to reduce the extent and seriousness of drug-related problems, such as adverse drug reactions, drug-disease interactions, drug-drug interactions, drug ineffectiveness and cost ineffectiveness. Several screening tools have been developed to guide practising healthcare professionals and researchers in reviewing the medication patterns of elderly patients; however, each of these tools has its own limitations. This review discusses a wide range of general prescription-, treatment- and patient-related issues that should be taken into account when reviewing medication patterns by implicit screening. These include generic and therapeutic substitution; potentially superfluous or inappropriate medications; potentially inappropriate dosages or duration of treatment; drug-disease and drug-drug interactions; under-treatment; making use of laboratory test results; patient adherence, experiences and habits; appropriate dosage forms and packaging. A broad selection of specific examples and references that can be used as a basis for explicit screening of medication patterns in outpatients is also offered.

Recognition and management of potential drug-drug interactions in patients on internal medicine wards

INTRODUCTION

Our aim was to study and possibly improve the clinical management of potential drug-drug interactions (pDDIs) in hospitalized patients by specific interventions.

METHODS

During the initial period, inpatients on three medical wards were screened for major and moderate pDDIs using the interaction screening program Pharmavista. During the second period, patients at discharge were screened similarly. After assessment of the detected pDDIs for clinical relevance, written recommendations and/or information about the pDDIs were sent to the treating physicians. Feedback from the physicians and implementation of the recommendations were analyzed.

RESULTS

During the initial period, 502 inpatients were exposed to 567 pDDIs, of which 419 (74%) were judged to be clinically relevant. Three hundred and forty-nine substantiated recommendations and 70 simple information leaflets were handed out to the physicians. Eighty percent (278 of 349) of the recommendations were accepted and implemented. During the second period, 792 patients at hospital discharge were exposed to 392 pDDIs, of which 258 (66%) were judged to be clinically relevant. Two hundred and forty-seven substantiated recommendations and 11 simple information leaflets were sent to the physicians. Seventy-three percent (180 of 247) of the recommendations were accepted. At hospital discharge, 47 of 71 interventions recommending checkable medication changes were implemented. One year after hospital discharge, 11 of 13 checked medication changes were still in place.

CONCLUSIONS

Clinically relevant pDDIs are common in patients on medical wards, and their management can be influenced by providing substantiated recommendations to physicians. Most changes in medication following such recommendations are still in place 1 year after discharge.

Clinical risk management of herb-drug interactions

The concomitant use of conventional and herbal medicines can lead to clinically relevant herb-drug interactions. Clinical risk management offers a systematic approach to minimize the untoward consequences of these interactions by paying attention to: (i) risk identification and assessment; (ii) development and execution of risk reduction strategies; and (iii) evaluation of risk reduction strategies. This paper reviews which steps should be explored or taken in these domains to improve the clinical risk management of adverse herb-drug interactions.