Prevalence of the prescription of potentially interacting drugs

Polypharmacy, drug-drug interactions, anticholinergic burden and cognitive outcomes: a snapshot from a community-dwelling sample of older men and women in northern Italy

Polypharmacy (PP) use is very common in older people and may lead to drug-drug interactions (DDIs) and anticholinergic burden (ACB) that may affect cognitive function. We aimed to determine the occurrence of PP, potential DDIs and ACB and their role in cognitive outcomes in an older population. Cross-sectional data from 636 community-dwelling adults (73.2 ± 6.0 SD, 58.6% women) participating in the NutBrain study (2019-2023) were analyzed. Participants were asked about their medication use, and data on potential DDIs and ACB were extracted. The associations of PP (≥ 5 drugs/day), potential DDIs, and ACB with mild cognitive impairment (MCI) and specific cognitive domains were assessed using logistic regression adjusted for confounders. Sex-stratified analysis was performed. Overall, 27.2% of the participants were exposed to PP, 42.3% to potential DDIs and 19% to cumulative ACB. Women were less exposed to PP and more exposed to ACB than men. In multivariate analysis, the odds of having MCI (24%) were three times higher in those with severe ACB (≥ 3) (OR 3.34, 95%CI 1.35-8.25). ACB was positively associated with poor executive function (OR 4.45, 95%CI 1.72-11.49) and specifically with the Frontal Assessment Battery and neuropsychological tests of phonological and semantic fluency. In sex-stratified analysis, ACB was statistically significantly associated with MCI and executive function in women and with memory in men. PP, potential DDIs and anticholinergics use are very common in community-dwelling older people. ACB exposure is associated with MCI, particularly with poor executive function. Clinicians are encouraged to be vigilant when prescribing anticholinergics.Trial registration: Trial registration number NCT04461951, date of registration July 7, 2020 (retrospectively registered, ClinicalTrials.gov).

Prevalence and factors associated with potential drug-drug interactions in prescriptions presented at private pharmacies in Mbarara city, southwestern Uganda

BACKGROUND

Drug-drug interactions (DDIs) influence the effectiveness of medication and thus determine the treatment outcomes of diseases managed with pharmacotherapy. This study aimed to determine the prevalence, severity, and factors associated with potential drug-drug interactions in prescriptions presented at private pharmacies in Mbarara city.

METHODS

DDIs were identified and classified basing on risk and severity using Lexicomp drug interaction database. STATA version 13 was used to analyze the collected data. Descriptive statistics were used to summarize the severity of potential DDIs identified. Bivariate and multivariate logistic regression was employed to identify different factors associated with the presence of potential DDIs.

RESULTS

A total of 295 prescriptions from 18 private pharmacies were studied and the prevalence of clinically significant potential DDIs was 37.6%. About half (149, 50.5%) of the patients were females, the majority (199, 67.5%) were adults 18-59 years of age whereas most (208, 70.5%) had a comorbid condition. Over one half (162, 54.9%) of the prescriptions were received from hospitals and majority of the prescriptions had 4 drugs prescribed (n = 175, 59.32%). Having one or more comorbidities and prescribing of therapeutic drug categories including anti-fungal, antihypertensives, analgesics, or corticosteroids were significantly associated with potential DDIs.

CONCLUSIONS

The prevalence of potential drug-drug interactions in outpatient setting in Mbarara city was high and majority of the potential DDIs were of moderate severity. Having 1 or more comorbidities and prescribing of therapeutic drug categories including antifungals, antihypertensives, analgesics, or corticosteroids were significantly associated with potential DDIs.

Implementation and assessment of a novel drug interaction tool (TLC-act) in an entry-to-practice doctor of pharmacy program

BACKGROUND AND PURPOSE

Drug-drug interaction (DDI) assessment is an important role that pharmacists have in practice. Students often struggle with this complex clinical reasoning skill. TLC-Act is a tool that was created to mirror the steps and clinical checkpoints that pharmacists complete when assessing DDIs. Through integration of TLC-Act in the pharmacy curriculum, students will be better prepared for assessing and evaluating DDIs when in practice.

EDUCATIONAL ACTIVITY AND SETTING

For the 2021-2022 academic year, an asynchronous educational activity to teach students how to use TLC-Act was created and implemented. Five videos that encompassed multiple facets of TLC-Act including an introduction to the tool and how to use it, an example application of the tool to a patient case, and the clinical utility of using TLC-Act in the hospital and community settings. Students were instructed to view all five videos and then complete a patient case that focused on the DDI between ciprofloxacin and metformin.

FINDINGS

A pre- and post-activity survey was disseminated to 640 students across the first three years of the program to gather students' perspectives on the educational activity. Overall, survey response rates were 32% for the pre- and 23% for the post-activity surveys.

SUMMARY

The TLC-Act educational activity improved students' skills with managing DDIs.

Prevalence of Drug-Drug Interactions in Older Community-Dwelling Individuals: A Systematic Review and Meta-analysis

BACKGROUND

Drug-drug interactions (DDIs) can lead to medication-related harm, and the older population is at greatest risk. We conducted a systematic review and meta-analysis to estimate DDI prevalence and identify common DDIs in older community-dwelling adults.

METHODS

PubMed and EMBASE were searched for observational studies published between 01/01/2010 and 10/05/2021 reporting DDI prevalence in community-dwelling individuals aged ≥ 65 years. Nursing home and inpatient hospital studies were excluded. Study quality was assessed using the Joanna Briggs Institute critical appraisal tool. Meta-analysis was performed using a random-effects model with logit transformation. Heterogeneity was evaluated using Cochran's Q and I². DDI prevalence and 95% confidence intervals (CIs) are presented. All analyses were performed in R (version 4.1.2).

RESULTS

There were 5144 unique articles identified. Thirty-three studies involving 17,011,291 community-dwelling individuals aged ≥ 65 years met inclusion criteria. Thirty-one studies reported DDI prevalence at the study-participant level, estimates ranged from 0.8% to 90.6%. The pooled DDI prevalence was 28.8% (95% CI 19.3-40.7), with significant heterogeneity (p < 0.10; I² = 100%; tau² = 2.13) largely explained by the different DDI identification methods. Therefore, 26 studies were qualitatively synthesised and seven studies were eligible for separate meta-analyses. In a meta-analysis of three studies (N = 1122) using Micromedex^®, pooled DDI prevalence was 57.8% (95% CI 52.2-63.2; I² = 69.6%, p < 0.01). In a meta-analysis of two studies (N = 809,113) using Lexi-Interact^®, pooled DDI prevalence was 30.3% (95% CI 30.2-30.4; I² = 6.8%). In a meta-analysis of two studies (N = 947) using the 2015 American Geriatrics Society Beers criteria^®, pooled DDI prevalence was 16.6% (95% CI 5.6-40.2; I² = 97.5%, p < 0.01). Common DDIs frequently involved cardiovascular drugs, including ACE inhibitor-potassium-sparing diuretic; amiodarone-digoxin; and amiodarone-warfarin.

CONCLUSIONS

DDIs are prevalent among older community-dwelling individuals; however, the methodology used to estimate these events varies considerably. A standardised methodology is needed to allow meaningful measurement and comparison of DDI prevalence.

Community pharmacist perceptions of drug-drug interactions

Background

Drug-drug interactions are preventable medication errors that can lead to serious negative outcomes for patients. Community pharmacists are uniquely positioned with their medication knowledge and role in prescription clinical assessment. However, workplace pressures and limitations related to computer systems can lead to drug-drug interactions being missed. There is a lack of information as to how community pharmacists assess drug interactions.

Methods

A qualitative study using key informant interviews of community pharmacists was conducted. Pharmacists were questioned on their perceptions and views of drug interactions.

Results

Eight community pharmacists participated. Four main themes were identified from the interviews: 1) pharmacist process of identifying drug interactions, 2) tools that help pharmacists assess and respond to drug interactions, 3) challenges in identifying and responding to clinically important drug interactions and 4) measures to avoid missing interactions.

Discussion

Community pharmacists experience challenges around their lack of access to patient information, which limits their ability to properly assess drug-drug interactions. In addition, increasing workload pressures have affected their ability to ensure their patients receive optimal pharmaceutical care. There is also a disconnect between the community pharmacy computer systems' alerts and their clinical relevancy to their specific patients. The overall burdens can lead to professional abstinence in the assessment of drug-drug interactions.

Conclusion

Community pharmacists are in an ideal position to prevent patients from experiencing drug-drug interactions. However, to further enable them to fulfill this role, increased access to patients' health records, decreased workload and better customization of computer alerts need to occur.

Factors associated with a basic common drug-drug interaction knowledge among emergency department medical personnel

Background

Drug-drug interactions (DDIs) are common but less concerning in clinical practice of time-sensitive situations. We aimed to identify factors associated with a basic common DDI knowledge among an emergency physician (EP), an emergency medicine resident (EMR), and an emergency care nurse (ECN).

Methods

This was a prospective cross-sectional study. EP, EMR, and ECN did the examination (multiple-choice questions, 40 points) about common DDI. Prespecified factors associated with examination scores were profession, longer emergency medicine experience, pharmacological training, last advanced cardiovascular life support (ACLS) training, DDI checker book, and application user experience. The outcome was an examination score to evaluate the ability of DDI knowledge. Univariable and multivariable means regressions were used.

Results

A total of 244 participants were enrolled. Factors associated with high examination score were EP (unadjusted mean difference 3.3 points, 95% confidence interval [CI] 2.1 to 4.5, p < 0.001), EMR (2.1, 95% CI 0.7 to 3.5, p 0.005) compared to ECN. Last ACLS training within 2 years (3.7, 95% CI 0.7 to 6.6, p 0.015), 2–4 years (3.4, 95% CI 0.4 to 6.5, p 0.027), and ≥4 years (4.4, 95% CI 1.2 to 7.6, p 0.007) were higher score than no ACLS training. Moreover, the DDI checker application experience user (1.7, 95% CI 0.6 to 2.8, p 0.003) also had a high score compared to the non-experienced user. After adjustment for all factors, EP (adjusted mean difference 3.3 points, 95% CI 1.8 to 4.7, p < 0.001), EMR (2.5, 95% CI 0.6 to 4.3, p 0.010) were higher scores compared to ECN. Meanwhile, the last ACLS training ≥4 years (3.3, 95% CI 0.1 to 6.6, p 0.042) was a higher score than no ACLS training.

Conclusion

EP, EMR, and the last ACLS training ≥4 years were associated with higher DDI knowledge than ECN and no ACLS training, respectively.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00623-0.

TLC-Act: A Novel Tool for Managing Drug Interactions

Background

Clinical decision support systems (CDSS) are used by pharmacists to assist in managing drug-drug interactions (DDIs). However, previous research suggests that such systems may perform suboptimally in providing clinically relevant information in practice.

Objectives

The primary objective of this study was to develop a novel DDI management tool to reflect the clinical thought process that a pharmacist uses when assessing a DDI. The secondary objective was to investigate practitioners' perceptions of this tool.

Methods

This study was conducted in 3 phases: development of the DDI management tool, implementation of the tool in clinical practice, and collection of practitioners' opinions of the tool through an online qualitative survey (although because of circumstances related to the COVID-19 pandemic, the study population for the survey phase included only pharmacy residents). A comprehensive literature search and analysis by an expert panel provided underlying context for the DDI management tool. The tool was validated through simulation against a known list of DDIs before implementation into practice by hospital pharmacists and pharmacy residents. Participating pharmacy residents were invited to provide feedback on the tool. Survey results were analyzed using descriptive statistics.

Results

The novel tool that was developed in this study (called TLC-Act) consisted of components important to a pharmacist when assessing a DDI, including the duration of concomitant use of the interacting medications and patient-specific risk factors. Study participants implemented the tool in clinical practice for a total of 6 weeks. Of the 28 pharmacy residents surveyed, 15 (54%) submitted a response, of whom 11 (73%) found the TLC-Act tool to be slightly more useful for assessing a DDI than usual care with the CDSS alone.

Conclusions

The TLC-Act tool maps out a pharmacist's clinical thought process when assessing a DDI in practice. This novel tool may be more useful than a CDSS alone for managing DDIs, as it takes into account other important factors pertinent to the assessment of a DDI.

Determination of potential drug-drug interactions in prescription orders dispensed in a community pharmacy setting using Micromedex® and Lexicomp®: a retrospective observational study

Background Community pharmacists have a role in identifying drug-drug interactions (DDIs) when processing prescription orders and dispensing medications to patients. The harmful effects of DDIs can be prevented or minimized by using an electronic DDI checker to screen for potential DDIs (pDDIs). However, different DDI checkers have variable rates of detecting pDDIs. Aim To estimate the prevalence of pDDIs in prescriptions dispensed in a community pharmacy setting using two electronic DDI databases and to evaluate the association between the pDDIs and contributory factors. Method Eligible prescription orders dispensed by a community pharmacy chain in Qatar from January to July 2020 were included in this retrospective observational study. For each prescription, Micromedex^® and Lexicomp^® were simultaneously used to identify pDDIs, and the interactions categorized based on severity and risk rating. Results Seven hundred-twenty prescriptions met the inclusion criteria, of which Micromedex^® and Lexicomp^® respectively identified 125 prescriptions (17.4%) and 230 prescriptions (31.9%) as having at least one pDDI. Moderate strength of agreement was found between Lexicomp^® and Micromedex^® in identifying pDDIs (Cohen's Kappa = 0.546). Micromedex^® classified 61.6% of DDIs as major severity, while Lexicomp^® classified 30.8% as major severity. The number of concurrent medications per prescription was significantly and positively associated with pDDI. Conclusion This study demonstrates a high prevalence of pDDIs among prescriptions dispensed in a community pharmacy setting. It is advisable that community pharmacists in Qatar, who typically do not have access to computerized patient profiles, use these DDI checkers to ensure all pDDIs are communicated to respective prescribers for appropriate action.

Comparison of Clinical Importance of Drug Interactions Identified by Hospital Pharmacists and a Local Clinical Decision Support System

Background

Drug-drug interactions (DDIs) may cause adverse drug events, potentially leading to hospital admission. Clinical decision support systems (CDSSs) can improve decision-making by clinicians as well as drug safety. However, previous research has suggested that pharmacists are concerned about discrepancies between CDSSs and common clinical practice in terms of severity ratings and recommended actions for DDIs.

Objectives

The primary objective was to characterize the level of agreement in terms of DDI severity ranking and actions recommended between the local CDSS and pharmacists. The secondary objectives were to determine the level of agreement among pharmacists concerning DDI severity, to determine the influence of the CDSS on clinicians' decision-making, and to review the literature supporting the severity rankings of DDIs identified in the study institution's database.

Methods

This 2-part survey study involved pharmacists and pharmacy residents working at 1 of 4 health organizations within the Lower Mainland Pharmacy Services, British Columbia, who were invited to participate by email. Participants were first asked to rank the severity of 15 drug pairs (representing potential DDIs) on a 5-point Likert scale and to select an action to manage each interaction. Participants were then given the CDSS severity classification for the same 15 pairs and again asked to select an appropriate management action.

Results

Of the estimated 500 eligible pharmacists, a total of 73 pharmacists participated, for a response rate of about 15%. For DDIs of moderate severity, most participants chose to monitor. For severe and contraindicated interactions, the severity ranking and action proposed by participants varied, despite the same severity classification by the CDSS. There was poor agreement among respondents about the severity of the various DDIs. Moreover, knowledge of the CDSS severity ranking did not seem to change the actions proposed by most respondents.

Conclusion

This study identified a gap between the local CDSS and clinical practice. There were discrepancies in terms of severity rankings and actions proposed to manage DDIs, particularly for severe and contraindicated DDIs. The current CDSS did not appear to have a large impact on clinical decision-making, which suggests that it may not be functioning to its full potential.

The Prevalence of Selected Potential Drug-Drug Interactions of Analgesic Drugs and Possible Methods of Preventing Them: Lessons Learned From the Analysis of the Real-World National Database of 38 Million Citizens of Poland

Introduction: Drug-drug interactions may lead to poor health outcomes, as well as increased costs and utilization of healthcare services. Unfortunately, real-world data continuously prove high prevalence of potential drug-drug interactions (pDDIs) worldwide. Among identified drivers, ageing, multimorbidity and polypharmacy play a very important role. With these factors being widespread, the need for implementation of strategies minimizing the burden of pDDIs becomes an urgency. This, however, requires a better understanding of the prevalence of pDDIs and the underlying causative factors.

Aim of study: To assess the real-world prevalence of pDDIs and its characteristics in the general population of Poland, using analgesic drugs as a model, and to find out whether pDDIs are caused by prescribing coming from the very same prescribers (co-prescribing).

Methods: A retrospective analysis of the 2018 dispensation data of the National Health Fund (NHF) - the only Polish public healthcare payer organization with nationwide coverage. We searched for selected pDDIs of non-steroidal anti-inflammatory drugs (NSAIDs) with antihypertensives, other NSAIDs (double use), oral glucocorticoids, oral anticoagulants, selective serotonin reuptake inhibitors (SSRIs), serotonin–norepinephrine reuptake inhibitors (SNRIs), and antiplatelet drugs; as well as opioides with SSRIs, SNRIs, gabapentinoids, and benzodiazepines. A pDDI was deemed present if two drugs standing in a possible conflict were dispensed within the same calendar month.

Results: Out of 38.4 million citizens of Poland, 23.3 million were dispensed prescribed drugs reimbursed by NHF in 2018. In this cohort, we have identified 2,485,787 cases of analgesic drug pDDIs, corresponding with 6.47% of the Polish population. Out of these, the most prevalent pDDI was caused by “NSAIDs + antihypertensives” (1,583,575 cases, i.e., 4.12% of the Polish population), followed by “NSAIDs + NSAIDs” (538,640, 1.40%) and “NSAIDs + glucocorticoids” (213,504, 0.56%). The most persistent pDDIs among those studied were caused by “Opioids + Gabapentinoids” (2.19, 95%CI: 2.16–2.22 months). On average, 76.63% of all cases of pDDIs were caused by drugs prescribed by the very same prescribers.

Conclusion: Based on high-quality, nationwide data, we have found a high prevalence of analgesic drugs-related pDDIs in Poland. Over ¾ of the identified pDDIs were caused by co-prescribing, i.e., prescriptions issued by the same prescribers. The significance of the problem, illustrated with our findings on analgesic drugs-related pDDIs in Poland, deserves much more scientific and policymaker attention.

Frailty and Co-Prescribing of Potentially Interacting Drugs in New Users of Warfarin

Background

Warfarin is underutilised in frail older people because of the fear of bleeding complications. Drug interactions are an independent bleeding risk factor. However, the extent to which potential drug interactions are taken into account at warfarin therapy initiation in frail patients is not known.

Objective

The objective of this study was to investigate the use of potentially interacting drugs increasing the bleeding risk before and after warfarin initiation in frail and non-frail patients.

Methods

We conducted an observational study including inpatients aged ≥ 60 years initiated on warfarin in a tertiary hospital in Adelaide, South Australia. Frailty status was assessed with the Reported Edmonton Frail Scale. Medication charts were reviewed before and after warfarin initiation.

Results

In total, 151 patients (102 non-frail and 49 frail) were included. Before warfarin initiation, the use of clopidogrel and acetaminophen was more common in frail patients compared with non-frail patients (25.5% vs 10.2%, p = 0.0135, 63.8% vs 35.7% p = 0.0014, respectively). The use of non-steroidal anti-inflammatory drugs, 9.2% in non-frail patients and 6.4% in frail patients before warfarin initiation, was completely stopped after warfarin initiation in both groups. The use of antiplatelet drugs decreased from 56.1% in non-frail patients and 66.0 % in frail patients to 12.2% and 14.9%, respectively. Instead, the use of drugs affecting the metabolism of warfarin or vitamin K increased in both groups. No statistically significant difference was seen in the exposure to interacting drugs between study groups after warfarin initiation. Acetaminophen, senna glycosides and cytochrome P450 2C9 inhibiting drugs were the most common interacting drugs at discharge used in 49.0%, 18.4% and 20.4% of non-frail patients and 53.2%, 29.8% and 19.1% of frail patients, respectively.

Conclusions

The overall frequency of potential drug interactions was moderate and frail patients were not exposed to warfarin drug interactions more often than non-frail patients. Further studies in larger study populations are required to verify these results.

Electronic supplementary material

The online version of this article (10.1007/s40266-020-00755-0) contains supplementary material, which is available to authorized users.

A pragmatic controlled trial to improve the appropriate prescription of drugs in adult outpatients: design and rationale of the EDU.RE.DRUG study

Introduction:

Pharmacological intervention is an important component of patient care. However, drugs are often inappropriately used. It is necessary for countries to implement strategies to improve the rational use of drugs, including independent information for healthcare professionals and the public, which must be supported by well-trained staff. The primary objectives of the EDU.RE.DRUG (Effectiveness of informative and/or educational interventions aimed at improving the appropriate use of drugs designed for general practitioners and their patients) study are the retrospective evaluation of rates of appropriate prescribing indicators (APIs) and the assessment of the effectiveness of informative and/or educational interventions addressed to general practitioners (GPs) and their patients, aimed at improving prescribing quality and promoting proper drug use.

Methods and analysis:

This is a prospective, multicentre, open-label, parallel-arm, controlled, pragmatic trial directed to GPs and their patients in two Italian regions (Campania and Lombardy). The study data are retrieved from administrative databases (Demographic, Pharmacy-refill, and Hospitalization databases) containing healthcare information of all beneficiaries of the National Health Service in the Local Health Units (LHUs) involved. According to LHU, the GPs/patients will be assigned to one of the following four intervention arms: (1) intervention on GPs and patients; (2) intervention on GPs; (3) intervention on patients; and (4) no intervention (control). The intervention designed for GPs consists of reports regarding the status of their patients according to the APIs determined at baseline and in two on-line Continuous Medical Education (CME) courses. The intervention designed for patients consists in flyers and posters distributed in GPs ambulatories and community pharmacies, focusing on correct drug use.

A set of indicators (such as potential drug–drug interactions, unnecessary duplicate prescriptions, and inappropriate prescriptions in the elderly), adapted to the Italian setting, has been defined to determine inappropriate prescription at baseline and after the intervention phase. The primary outcome was a composite API.

Ethics and dissemination:

The study was approved by the Ethics Committee of the University of Milan on 7th June 2017 (code 15/17). The investigators will communicate trial results to stakeholders, collaborators, and participants via appropriate presentations and publications.

Registration details: NCT04030468. EudraCT number 2017-002622-21

Use of the French healthcare insurance database to estimate the prevalence of exposure to potential drug-drug interactions

PURPOSE

Drug-drug interactions (DDIs) require monitoring in an aging population with increasing polypharmacy exposure. We aimed to estimate the prevalence of exposure to potential DDIs using the French healthcare insurance system database, for six DDIs with various clinical relevance: angiotensin II receptor blockers or angiotensin-converting enzyme inhibitors and nonsteroidal anti-inflammatory drugs (ARBs-ACEIs + NSAIDs), antiplatelet agents and NSAIDs (AAP + NSAIDs), serotonergic drugs and tramadol (SD + T), statins and macrolides (S + M), oral anticoagulant and NSAIDs (OAC + NSAIDs), and colchicine and macrolides (C + M).

METHODS

We used exhaustive healthcare data from a 1/97th random sample of the population covered by the French health insurance system (EGB) between 2006 and 2016. Exposure to a DDI was defined as overlapping exposure to two interacting drugs. The prevalence of exposure was estimated by year.

RESULTS

Prevalence of exposure in 2016 was estimated at 3.7% for ARBs-ACEIs + NSAIDs, 1.5% for AAP + NSAIDs, 0.76% for SD + T, 0.36% for S + M, 0.24% for AOC + NSAIDs, and 0.02% for C + M. In 26% to 58% of episodes of exposure, the two interacting drugs were prescribed by the same physician and dispensed by the same pharmacy the same day. Between 2006 and 2016, the yearly prevalence was increasing for SD + T and for DDIs involving NSAIDs, and it was decreasing for those involving macrolides.

CONCLUSION

Exposures to potential DDIs in France are not uncommon with a high proportion resulting from a co-prescription by the same physician. Monitoring the prevalence of exposure to DDIs is needed to implement prevention measures. Administrative data enable this surveillance in large and representative cohorts.

Art of Making Artificial Liver: Depicting Human Liver Biology and Diseases in Mice

Advancement in both bioengineering and cell biology of the liver led to the establishment of the first-generation humanized liver chimeric mouse (HLCM) model in 2001. The HLCM system was initially developed to satisfy the necessity for a convenient and physiologically representative small animal model for studies of hepatitis B virus and hepatitis C virus infection. Over the last two decades, the HLCM system has substantially evolved in quality, production capacity, and utility, thereby growing its versatility beyond the study of viral hepatitis. Hence, it has been increasingly employed for a variety of applications including, but not limited to, the investigation of drug metabolism and pharmacokinetics and stem cell biology. To date, more than a dozen distinctive HLCM systems have been established, and each model system has similarities as well as unique characteristics, which are often perplexing for end-users. Thus, this review aims to summarize the history, evolution, advantages, and pitfalls of each model system with the goal of providing comprehensive information that is necessary for researchers to implement the ideal HLCM system for their purposes. Furthermore, this review article summarizes the contribution of HLCM and its derivatives to our mechanistic understanding of various human liver diseases, its potential for novel applications, and its current limitations.

Risk factors for potential drug-drug interactions in patients with chronic obstructive pulmonary disease

Potential drug-drug interactions (pDDIs) are especially frequent in patients with chronic obstructive pulmonary disease (COPD) who, if hospitalized, experience, on average 6.5 pDDIs on admission, and 7.2 on discharge. The aim of our study was to identify and analyze risk and/or protective factors for occurrence of pDDIs in hospitalized patients with COPD. Main outcome was occurrence of pDDIs in COPD patients ascertained by Medscape, Epocrates, and Micromedex interaction checkers. The most serious pDDIs (contraindicated/serious/major/use alternative) were found in 16 (22%), 8 (11%), and 35 (49%) patients, according to the Medscape, Epocrates, and Micromedex, respectively. The COPD patients who were prescribed more drugs (especially antiarrhythmic and anticoagulants), by several independent prescribers, and having more comorbidities, were more prone to experience a pDDI; the only protective factor against pDDIs was age of the patients. In conclusion, COPD patients with the abovementioned risk factors should have their therapy more intensely monitored for pDDIs.

Concomitant use of drugs known to cause interactions with oral antiplatelets-polypharmacy in acute coronary syndrome outpatients in Finland

PURPOSE

Use of oral antiplatelets (OAPs) is essential for preventing thrombotic events in patients with acute coronary syndrome (ACS). Effects of clopidogrel, prasugrel, and ticagrelor may be enhanced due to pharmacodynamic interactions, but as CYP substrates, they are prone to pharmacokinetic interactions too. The aim was to study polypharmacy in ACS patients following hospital discharge.

METHODS

This observational drug utilization study linked patient-level data from nationwide registers. The study population consisted of adult ACS patients discharged from Finnish hospitals in 2009-2013. Logistic regression was used to model the probability of drug-drug interactions with odd ratios for predefined predictors such as age, gender, and ACS type.

RESULTS

In the cohort of 54,416 ACS patients, 91% of those treated with OAP received clopidogrel. Of clopidogrel-treated patients, 12% purchased warfarin at least once while on clopidogrel treatment. Old age, male sex, ST-elevation myocardial infarction as index event, and a history of previous ACS events were associated with an increased risk of warfarin-OAP interaction (p < 0.001 for all). Ibuprofen, and serotonergic drugs tramadol, citalopram, and escitalopram were the next most common drugs causing pharmacodynamic interactions. In general, concomitant use of drugs known to cause pharmacokinetic interactions was rare, but both esomeprazole and omeprazole were prescribed in more than 6% of clopidogrel-treated patients.

CONCLUSIONS

Warfarin and ibuprofen were the most commonly used concomitant medications causing pharmacodynamic interactions and potentially increasing the risk of bleeding in OAP-treated patients. Esomeprazole and omeprazole were used in clopidogrel-treated patients although there are alternatives available for gastric protection.

[Potential drug interactions in adults and the elderly in primary health care]

The objective of the present study was to characterize the potential drug interactions (PDI), estimating the factors associated to their occurrence in adults and the elderly assisted by the Programa Médico de Família de Niterói, Rio de Janeiro. This is a sub-study of STUDY DIGITALIS, which included individuals enrolled in the Niteroi Family Medical Program (45-99 years). In this study, 341 individuals with a prescription of two or more drugs were analyzed. The classification of PDI followed MICROMEDEX. There were 113 different interactions. Of the total number of individuals, 63.6% had at least one PDI. The variables with higher probability of PDI were: lower level of schooling; income less than R$800.00; absence of health plan; previous diagnosis of hypertension and diabetes; use of 5 or more medications prescribed. After adjustment, the variables previous diagnosis of hypertension and diabetes and use of 5 or more prescription drugs remained statistically significant. Careful management of primary care treatment with monitoring is important in patients with PDI, especially in patients who are more susceptible.

Potential drug-drug interactions and associated factors among hospitalized cardiac patients at Jimma University Medical Center, Southwest Ethiopia

Background

Concomitant use of several drugs for a patient is often imposing increased risk of drug-drug interactions. Drug-drug interactions are a major cause for concern in patients with cardiovascular disorders due to multiple co-existing conditions and the wide class of drugs they receive. This study is aimed to assess the prevalence of potential drug-drug interactions and associated factors among hospitalized cardiac patients at medical wards of Jimma University Medical Center, Southwest Ethiopia.

Methods

A hospital-based prospective observational study was conducted among hospitalized cardiac adult patients based on the inclusion criteria. Patient-specific data were collected using structured data collection tool. Potential drug-drug interaction was analyzed using Micromedex 3.0 DRUG-REAX^® System. Data were analyzed using statistical software package, version 20.0. To identify the independent predictors of potential drug-drug interaction, multiple stepwise backward logistic regression analysis was done. Statistical significance was considered at a p-value < 0.05. Written informed consent from patients was obtained and the patients were informed about confidentiality of the information obtained.

Results

Of the total 200 patients, majority were male (52.50%) and with a mean(±standard deviation) age of 42.54(±7.89) years. Out of 673 patients' prescriptions analyzed, 521 prescriptions comprised potential drug interactions and it was found that 967 drug interactions were present. The prevalence rate of potential drug-drug interactions among the study unit was 4.83 per patient and 1.44 per prescription regardless of the severity during their hospital stay. Overall the prevalence rate of potential drug interactions was 74.41%. Older age (adjusted odds ratio (95% confidence interval): 1.067 (2.33-27.12), p = 0.049), long hospital stay (⩾7 days) (adjusted odds ratio (95% confidence interval): 2.80 (1.71-4.61), p = 0.024), and polypharmacy (adjusted odds ratio (95% confidence interval): 1.64 (0.66-4.11), p = 0.041) were independent predictors for the occurrence of potential drug-drug interactions.

Conclusion

This study demonstrated a high prevalence of potential DIs among hospitalized cardiac patients in medical wards due to the complexity of pharmacotherapy. The prevalence rate is directly related to age, number of prescribed drugs, and length of hospital stay. Pharmacodynamic drug-drug interaction was the common mechanism of drug-drug interactions. Therefore, close monitoring of hospitalized patients is highly recommended.

Potentially inappropriate medications prescribing according to Beers criteria among elderly outpatients in Jordan: a cross sectional study

Background

Due to aging, along with its associated physiological changes, older adults are extremely vulnerable to be afflicted with multiple chronic conditions (multimorbidity). Accordingly, prescribing a large number of drugs to older adults would be inevitable. Resulted complex drug regimens can lead to prescribing of Potentially Inappropriate Medications (PIMs) with subsequent negative health and economic outcomes.

Objectives

The main objective of this study is to investigate the prevalence and predictors of PIMs prescribing among Jordanian elderly outpatients, using the last updated version of the American Geriatrics Society (AGS) Beers Criteria (2015 version).

Methods

A Unicenter, cross-sectional study were data was assessed using medical records of included study subjects conducted over three months period from beginning of October to the end of December 2016 at King Abdullah University Hospital, Al Ramtha, Jordan. Our study included patients aged 65 years or above who visited the outpatient clinics at King Abdullah University hospital (KAUH) and were prescribed at least one oral medication during the study period. PIMs were identified for these patients and further classified according to the 2015 AGS Beers Criteria. We measured the prevalence of PIMs prescribed among elderly outpatients in Jordan.

Results

A total of 4622 eligible older adults were evaluated in this study, of whom 62.5% (n=2891) were found to have at least one PIM prescribed during the three months study period. 69% of identified PIMs were medications to be used with caution in elderly, 22% were medications to avoid in many or most older adults, 6.3% were medications to be avoided or have their dosage adjusted based on kidney function in older adults, 2.04% medications were to avoid in older adults with specific diseases/syndromes, and 1.6% were potentially clinically important non-anti-infective drug-drug interactions to be avoided in older adults. Female gender and polypharmacy were found to be significant predictors of PIMs use among elderly.

Conclusions

Potentially Inappropriate Medication prescribing is common among Jordanian elderly outpatients. Female gender and polypharmacy are associated with more PIMs prescribing and so need further attention.

Countrywide prevalence of critical drug interactions in Hungarian outpatients: a retrospective analysis of pharmacy dispensing data

Background

Drug-drug interactions (DDIs) present a significant source of adverse drug reactions. Despite being one of the commonly cited risks to patient safety, prevention of DDIs still poses a challenge to healthcare systems. The prevalence of DDIs can be used as a quality indicator for the safety of prescribing. With the analysis of drug utilization databases, real-world data on critical DDIs can be obtained. The aim of this study was to establish a list of critical DDIs and estimate their prevalence in the Hungarian outpatient population.

Methods

Since there is no conclusive and generally accepted repository of high-risk DDIs, a systematic search of the literature for consensus-based lists was performed. Based on these results and their analysis with 5 interaction compendia, we propose a simple methodology to identify critical combinations. Present study focused on DDIs which are (1) of high clinical importance thus being most likely to cause significant harm if not detected, (2) well-supported by available evidence and (3) affect drugs which are routinely dispensed in the community pharmacy setting. A retrospective analysis of prescriptions filled between 2013 and 2016 was performed. The source of drug utilization data was the IQVIA’s national prescription fill database. The number of interacting drug pairs dispensed at the same time to the same patient was established.

Results

After excluding drugs with low dispensing rates, the analysis covered 39 DDIs. The distribution of risk categories of the analysed DDIs was inconsistent among different drug interaction compendia. The total number of prescriptions filled varied between 173924449 and 176368468 per year. The prevalence of the selected potential DDIs ranged from 0.00 to 355.89 per 100000 prescriptions per year. There was significant variation between how the number of cases had changed for each DDI throughout the study period, no general tendency could have been described.

Conclusions

There were 1.8 million cases of co-dispensing each year, where prescribers’ and community pharmacists’ role in recognizing and managing potentially serious interactions was or would have been critical. The method presented to identify high-risk DDIs can serve as a starting point for the much-needed improvement of routine interaction screening.

Electronic supplementary material

The online version of this article (10.1186/s40360-019-0311-0) contains supplementary material, which is available to authorized users.

Preventing potential drug-drug interactions through alerting decision support systems: A clinical context based methodology

BACKGROUND

The effectiveness of the clinical decision support systems (CDSSs) is hampered by frequent workflow interruptions and alert fatigue because of alerts with little or no clinical relevance. In this paper, we reported a methodology through which we applied knowledge from the clinical context and the international recommendations to develop a potential drug-drug interaction (pDDI) CDSS in the field of kidney transplantation.

METHODS

Prescriptions of five nephrologists were prospectively recorded through non-participatory observations for two months. The Medscape multi-drug interaction checker tool was used to detect pDDIs. Alongside the Stockley's drug interactions reference, our clinicians were consulted with respect to the clinical relevance of detected pDDIs. We performed semi-structured interviews with five nephrologists and one informant nurse. Our clinically relevant pDDIs were checked with the Dutch "G-Standard". A multidisciplinary team decided the design characteristics of pDDI-alerts in a CDSS considering the international recommendations and the inputs from our clinical context. Finally, the performance of the CDSS in detecting DDIs was evaluated iteratively by a multidisciplinary research team.

RESULTS

Medication data of 595 patients with 788 visits were collected and analyzed. Fifty-two types of interactions were most common, comprising 90% of all pDDIs. Among them 33 interactions (comprising 77% of all pDDIs) were rated as clinically relevant and were included in the CDSS's knowledge-base. Of these pDDIs, 73% were recognized as either pseudoduplication of drugs or not a pDDI when checked with the Dutch G-standard. Thirty-three alerts were developed and physicians were allowed to customize the appearance of pDDI-alerts based on a proposed algorithm.

CONCLUSION

Clinical practice contexts should be studied to understand the complexities of clinical work and to learn the type, severity and frequency of pDDIs. In order to make the alerts more effective, clinicians' points of view concerning the clinical relevance of pDDIs are critical. Moreover, flexibility should be built into a pDDI-CDSS to allow clinicians to customize the appearance of pDDI-alerts based on their clinical context.

Prescription of proton pump inhibitors in older adults with complex polytherapy

OBJECTIVES

Prescription of proton pump inhibitors (PPIs) may be a source of potentially clinically relevant drug-drug interactions (DDIs) and related complications for elderly patients with complex polytherapy at discharge from hospital. The aim of the study was to identify, through the analysis of hospital discharge records, the co-administrations (PPIs + one or more drugs potentially generating DDIs) hypothetically leading to severe consequences according to the literature and online databases. Subsequently, alternatives to PPIs were evaluated for the treatment of gastric acidity and ulcers.

METHODS

The medical records of 1288 patients, discharged from a geriatric ward at the Città della Salute e della Scienza Hospital in Turin from January 2012 to December 2013, were collected in an Excel database for analysis of DDIs using the literature and online sources such as Micromedex. RESULTS : Six hundred and sixty-three of the 1288 clinical folders had a PPI prescription. A list of 18 drugs considered potentially hazardous and able to trigger a DDI when co-administrated with PPIs was drafted; the frequencies of the co-prescriptions of each PPI with one of the listed drugs were esomeprazole 65.38%, lansoprazole 52.87%, omeprazole 48.19% and pantoprazole 37.11%. An analysis of these co-prescriptions, according to Micromedex classification, gave a percentage of major interactions of 11.01% over 663 clinical folders including a PPI.

CONCLUSIONS

This study provides a collection of potentially hazardous drug associations and helpful suggestions to improve the quality of prescriptions for elderly patients and strengthens the case for synergic work between doctors and pharmacists in the wards.

All-cause mortality and antipsychotic use among elderly persons with high baseline cardiovascular and cerebrovascular risk: a multi-center retrospective cohort study in Italy

BACKGROUND

Little is known about the comparative risk of death with atypical or conventional antipsychotics (APs) among persons with cardiovascular or cerebrovascular disease (CCD).

RESEARCH DESIGN AND METHODS

A cohort study was conducted using five Italian claims databases. New atypical AP users with CCD aged ≥65 (reference) were matched to new conventional AP users. Mortality per 100 person-years (PYs) and hazard ratios (HR), estimated using Cox models, were reported. Incidence and risk of death were estimated for persons having drug-drug interactions. Outcome occurrence was evaluated 180 days after AP initiation.

RESULTS

Overall 24,711 and 27,051 elderly new conventional and atypical AP users were identified. The mortality rate was 51.3 and 38.5 deaths per 100 PYs for conventional and atypical AP users. Mortality risk was 1.33 (95%CI: 1.27-1.39) for conventional APs. There was no increased mortality risk with single drug-drug interactions (DDIs) vs. no DDI. AP users with ≥1 DDI had a 29% higher mortality risk compared to no DDI in the first 90 days of treatment (HR: 1.29 (95% CI: 1.00-1.67)).

CONCLUSIONS

Conventional APs had a higher risk of death than atypical APs among elderly persons with CCD. Having ≥1 DDI was associated with an increased risk of death.

Pattern and Appropriateness of Medicines Prescribed to Outpatients at a University Hospital in Northwestern Ethiopia

The study assessed the pattern and appropriateness of medicines prescribed to outpatients at Gondar University Referral Hospital in northwestern Ethiopia. An institution-based cross-sectional study was employed, through interviews and prescription reviews, among 346 patients at the outpatient pharmacy, from 2nd to 20th of May 2016. Data on sociodemographic profile of patients and medicines prescribed to them were collected. A mean of 1.72 medicines per encounter was prescribed, over a third of the total being anti-infectives. Patients were able to get about 85% of these medicines. An unskilled government employee would be required to work more than one and a half day to be able to afford the average priced medicine. Among prescriptions with two or more medicines, more than a third had at least one potential drug-drug interaction (PDDI), the commonest pair containing amoxicillin and doxycycline. Being male, being older (50–59 years), and increased number of medicines were associated with higher likelihood of PDDIs. In conclusion, the number of medicines prescribed per encounter was up to accepted standard. However, their availability fell short, together with considerable cost. Regarding appropriateness, a significant proportion of potential drug-drug interactions is identified and associated with patient's sex, age, and number of medicines prescribed.

Pharmacological treatment of depression in geriatric chronic pain patients: a biopsychosocial approach integrating functional restoration

INTRODUCTION

A recent literature review concluded that the comorbidity of chronic pain and depression in adults is approximately 50%-65%. Physical and cognitive declines, concurrent multiple health conditions, and complex medication regimens add to the unique and complex challenges of effectively treating pain in particularly geriatric populations. Interdisciplinary medical intervention and monitoring for psychiatric sequelae, such as depression, cognitive change, and synergistic physical side effects are necessary. Areas covered: This review covers an extensive multi-database wide search of the pharmacotherapy of pain and depression in older adults, including biopsychosocial approaches. One of these, on which this review focuses, is Functional Restoration, an interdisciplinary application of quantified physical rehabilitation, case management, and cognitive behavioral and educational therapies to achieve improved well- being and better physical functioning. The biopsychosocial model incorporates an overview of the overlapping and interactive dimensions of a patient's life and addresses them within a comprehensive plan of treatment. Expert commentary: A multifactorial, rather than a single factor approach to the treatment of complicated health care problems such as chronic pain in an elderly patient is emphasized as an important change in perspective for the health care provider.

Drug prescription appropriateness in the elderly: an Italian study

Purpose

Correct drug prescription in the elderly is a difficult task that requires careful survey of the current pharmacological therapies. In this article, we reviewed the drug prescriptions provided to 860 persons aged 65 years or over, residing in a small city of Lombardy, Italy.

Methods

Subjects were recruited from a local nursing home, the Pavia and Vigevano Neuropsychological Center for Alzheimer’s Disease, general practitioners’ offices, and the local University of the Third Age. For each patient, the amount of potentially inappropriate prescriptions (PIPs), sedative and anticholinergic load (SL and AL, respectively), and drug–drug interactions were evaluated.

Results

Widespread polypharmacy, giving rise to 10.06% of PIPs in the whole collection of prescriptions, was observed. In particular, PIPs mainly concern drugs acting at the central nervous system level, mostly benzodiazepines and antipsychotics. Moreover, approximately one-fourth of the subjects had an elevated SL and approximately one-tenth a high AL. Drug–drug interactions were frequent (266 requiring medical attention), up to five for each single patient. Of concern was the underuse of antidementia drugs: only 20 patients received a cholinesterase inhibitor or memantine, although 183 patients were potentially suitable for this treatment.

Conclusion

These results demonstrate the need to develop novel strategies aimed at improving the quality of drug prescription.

Statin intolerance: diagnosis and remedies

Despite the efficacy of statins in reducing cardiovascular events in both primary and secondary prevention, the adherence to statin therapy is not optimal, mainly due to the occurrence of muscular adverse effects. Several risk factors may concur to the development of statin-induced myotoxicity, including patient-related factors (age, sex, and race), statin properties (dose, lipophilicity, and type of metabolism), and the concomitant administration of other drugs. Thus, the management of patients intolerant to statins, particularly those at high or very high cardiovascular risk, involves alternative therapies, including the switch to another statin or the use of intermittent dosage statin regimens, as well as nonstatin lipid lowering drugs (ezetimibe and fibrates) or new hypolipidemic drugs such as PCSK9 monoclonal antibodies, the antisense oligonucleotide against the coding region of human apolipoprotein B mRNA (mipomersen), and microsomal triglyceride transfer protein inhibitor lomitapide. Ongoing clinical trials will reveal whether the lipid-lowering effects of alternative therapies to statins can also translate into a cardiovascular benefit.

Incidence rate and pattern of clinically relevant potential drug-drug interactions in a large outpatient population of a developing country

The objective of this study was to determine incidence rate, type, and pattern of clinically relevant potential drug-drug interactions (pDDIs) in a large outpatient population of a developing country. A retrospective, descriptive cross-sectional study was conducted on outpatients' prescriptions in Khorasan Razavi province, Iran, over 12 months. A list of 25 clinically relevant DDIs, which are likely to occur in the outpatient setting, was used as the reference. Most frequent clinically relevant pDDIs, most common drugs contributing to the pDDIs, and the pattern of pDDIs for each medical specialty were determined. Descriptive statistics were used to report the results. In total, out of 8,169,142 prescriptions, 6,096 clinically relevant pDDIs were identified. The most common identified pDDIs were theophyllines-quinolones, warfarin-nonsteroidal anti-inflammatory drugs, benzodiazepines-azole antifungal agents, and anticoagulants-thyroid hormones. The most common drugs contributing to the identified pDDIs were ciprofloxacin, theophylline, warfarin, aminophylline, alprazolam, levothyroxine, and selegiline. While the incidence rate of clinically relevant pDDIs in prescriptions of general practitioners, internists, and cardiologists was the highest, the average pDDI incidence per 10,000 prescriptions of pulmonologists, infectious disease specialists, and cardiologists was highest. Although a small proportion of the analyzed prescriptions contained drug pairs with potential for clinically relevant DDIs, a significant number of outpatients have been exposed to the adverse effects associated with these interactions. It is recommended that in addition to training physicians and pharmacists, other effective interventions such as computerized alerting systems and electronic prescribing systems be designed and implemented.

Clinically important drug-drug interactions in poly-treated elderly outpatients: a campaign to improve appropriateness in general practice

AIMS

The aim was to assess the impact of a campaign for general practitioners (GPs) to reduce clinically-important drug-drug interactions (DDIs) in poly-treated elderly patients.

METHODS

We compiled a list of 53 DDIs and analyzed reimbursed prescriptions dispensed to poly-treated (≥four drugs) elderly (>65 years) patients in the Emilia Romagna region during January 2011-June 2011 (first pre-intervention period), January 2012-June 2012 (second pre-intervention period) and January 2013-June 2013 (post-intervention period). Educational initiatives to GPs were completed in July 2012-December 2012. Pre-test/post-test analysis (2013 vs. 2012) was performed, also using predicted 2013 data (P < 0.01 for statistical significance).

RESULTS

Despite the slight increase in poly-therapy rate (16% in 2013, +1.5% from 2011), we found a stable or slightly declining number of potential DDIs for each elderly poly-treated patient (~1.5). In 2013, 11 DDIs exceeded 5% of prevalence rate: antidiabetics-β-adrenoceptor blockers ranked first (20.3%), followed by ACE Inhibitors (ACEIs)/sartans-non steroidal anti-inflammatory drugs (NSAIDs) (16.4%), diuretics-NSAIDs (13.6%), selective serotonin re-uptake inhibitors (SSRIs)-NSAIDs/acetyl salicylic acid (ASA) (12.7%) and corticosteroids-NSAIDs/ASA (9.7%). A remarkable reduction emerged for NSAID-related DDIs (diuretics-NSAIDs peaked -14.5%; P < 0.01), whereas prevalence of antidiabetics-β-adrenoceptor blockers increased (+7.9%; P < 0.01). When using predicted values, the statistical significance disappeared for antidiabetics-β-adrenoceptor blockers (+1.3%; P = 0.04), whereas it persisted for almost all NSAIDs-related DDIs: ACEIs/sartans-NSAIDs (-3.0%), diuretics-NSAIDs (-6.0%), SSRIs-NSAIDs/ASA (-5.9%).

CONCLUSIONS

This campaign contained the burden of DDIs in poly-treated elderly patients by 1) reducing most prevalent DDIs, especially NSAIDs-related DDIs and 2) balancing the observed rise in poly-therapy rate with stable rate in overall prescriptions of potentially interacting drugs per patient.

Co-prescription trends in a large cohort of subjects predict substantial drug-drug interactions

Pharmaceutical prescribing and drug-drug interaction data underlie recommendations on drug combinations that should be avoided or closely monitored by prescribers. Because the number of patients taking multiple medications is increasing, a comprehensive view of prescribing patterns in patients is important to better assess real world pharmaceutical response and evaluate the potential for multi-drug interactions. We obtained self-reported prescription data from NHANES surveys between 1999 and 2010, and confirm the previously reported finding of increasing drug use in the elderly. We studied co-prescription drug trends by focusing on the 2009-2010 survey, which contains prescription data on 690 drugs used by 10,537 subjects. We found that medication profiles were unique for individuals aged 65 years or more, with ≥98 unique drug regimens encountered per 100 subjects taking 3 or more medications. When drugs were viewed by therapeutic class, it was found that the most commonly prescribed drugs were not the most commonly co-prescribed drugs for any of the 16 drug classes investigated. We cross-referenced these medication lists with drug interaction data from Drugs.com to evaluate the potential for drug interactions. The number of drug alerts rose proportionally with the number of co-prescribed medications, rising from 3.3 alerts for individuals prescribed 5 medications to 11.7 alerts for individuals prescribed 10 medications. We found 22% of elderly subjects taking both a substrate and inhibitor of a given cytochrome P450 enzyme, and 4% taking multiple inhibitors of the same enzyme simultaneously. By examining drug pairs prescribed in 0.1% of the population or more, we found low agreement between co-prescription rate and co-discussion in the literature. These data show that prescribing trends in treatment could drive a large extent of individual variability in drug response, and that current pairwise approaches to assessing drug-drug interactions may be inadequate for predicting real world outcomes.

Potentially inappropriate medication use in older patients in Swiss managed care plans: prevalence, determinants and association with hospitalization

Objectives

To describe the prevalence and determinants of potentially inappropriate medication (PIM) use and association with hospitalizations in an elderly managed care population in Switzerland.

Methods

Using health care claims data of four health insurers for a sample of managed care patients 65 years of age and older to compare persons on PIM with persons not on PIM. Beers' 2012 and PRISCUS criteria were used to determine the potential inappropriateness of prescribed medications. The sample included 16′490 elderly patients on PIM and 33′178 patients not on PIM in the time period of January 1, 2008 through December 31, 2012. Prevalence estimates are standardized to the population of Switzerland. Associations between PIM and hospitalizations were examined by multivariate Cox regression analyses controlling for possible confounding variables.

Results

The estimated prevalence of PIM use in our managed care sample was 22.5%. Logistic regression analysis showed that number of different medications used in the previous year, total costs in the previous year and hospitalization in the previous year all significantly increased the likelihood of receiving PIM. Multiple Cox regression analysis revealed that those on cumulative levels of PIM use acted significantly as a factor related to greater hospitalization rates: the adjusted HR was 1.13 (95% CI 1.07–1.19) for 1 PIM, 1.27 (95% CI 1.19–1.35) for 2 PIM, 1.35 (95% CI 1.22–1.50) for 3 PIM, and 1.63 (95% CI 1.40–1.90) for more than 3 PIM compared to no PIM use.

Conclusions

The prevalence of PIM in managed care health plans are widely found but seem to be much lower than rates of non-managed care plans. Furthermore, our study revealed a significant association with adverse outcomes in terms of hospitalizations. These findings stress the need for further development of interventions to decrease drug-related problems and manage patients with multiple chronic conditions.

Potentially inappropriate prescribing in elderly outpatients in Croatia

PURPOSE

The purpose of this study was to determine the prevalence of inappropriate prescribing to the elderly and to identify possible gender-related differences in prescribing certain potentially inappropriate medications (PIMs) to outpatients by using large administrative prescription database.

METHODS

Medications prescribed for elderly outpatients (≥ 65 years) in Primorsko-Goranska County, Croatia, who received five or more different drugs simultaneously in 2010, were analyzed. The prevalence of potentially inappropriate drugs prescribed to the elderly was assessed using the new comprehensive protocol developed by authors Mimica Matanović and Vlahović-Palčevski.

RESULTS

A total of 62.4 % of patients received at least one medication with unfavorable benefit/risk ratio in the elderly. Female patients were given inappropriate medications in a significantly higher percentage than men (69.3 % vs. 50.5 %; p < 0.001). The average number of prescriptions for PIMs that should have been avoided with certain diseases or conditions was 0.88 per patient in the survey. The most common drug combination potentially leading to serious drug-drug interactions (DDIs) included an angiotensin-converting enzyme (ACE) inhibitor and a potassium supplement.

CONCLUSIONS

Our study has shown that every tenth medication prescribed to a patient > 65 years and receiving five or more drugs was potentially inappropriate. Elderly women were prescribed PIMs more often than men. Drugs of concern in female patients were benzodiazepines, antidepressants, and nonsteroidal anti-inflammatory drugs (NSAIDs). In male patients, there was a significantly higher proportion of possible interactions with warfarin, theophylline, and medications affecting the cardiovascular system, such as ACE inhibitors and amiodarone.