Contraindicated Drug Combinations Research Articles

Polypharmacy, anticholinergic burden and drug-drug interaction assessment in people with four-class-resistant HIV: data from the PRESTIGIO registry.

To evaluate polypharmacy, anticholinergic burden (ACB) and drug-drug interactions (DDIs) in people with four-class-resistant HIV (4DR-PWH). We performed a cross-sectional study, including 4DR-PWH from the PRESTIGIO Registry taking at least one non-antiretroviral drug. Polypharmacy was defined as taking five or more non-antiretroviral drugs. ACB was calculated using the ACB scale: 0 = no AC effect, 1-2 = low/moderate risk, ≥3 = high AC risk. Participants' characteristics by ACB score were compared using the Kruskal-Wallis test, and Spearman's correlation coefficient was used to assess linear relationships. DDIs were evaluated using the Liverpool database. Overall, 172 4DR-PLWH were evaluated: 75.6% males, median age 49.9 years (IQR = 45.6-56), 62 (27.1%) on polypharmacy, 124 (72.1%) using a boosting agent and 72 (41.8%) with four or more antiretrovirals. Based on ACB, 128 (74.45%), 33 (19.2%) and 11 (6.4%) had a no, low/moderate and high AC risk, respectively. The most common AC drugs were β-blockers (12.2%), diuretics (8.7%) and antidepressants (8.7%). The high ACB was significantly related to the number of drugs/person (r = 0.33, P < 0.0001) and the number of clinical events (r = 0.222, P = 0.004). Overall, 258 DDIs were found between antiretrovirals and co-medications in 115 (66.8%) PWH, and 14 (8.1%) PWH received contraindicated drug combinations. In 4DR-PWH, polypharmacy, DDIs and the proportion of people with moderate/high AC burden were high. In 4DR-PWH undetectability achievement and maintenance is the priority and use of boosted PIs is common. A strict collaboration (infectious diseases specialists, virologists, pharmacologists) is needed to limit the risk of ACB and DDIs and to explore the advantages of new antiretrovirals.

Current Prescription Status of Contraindicated Drug Combinations Causing Serotonin Syndrome: Analysis of HIRA-NPS Data

Current Prescription Status of Contraindicated Drug Combinations Causing Serotonin Syndrome: Analysis of HIRA-NPS Data

Assessment of drug-drug interactions among patients with psychiatric disorders: A clinical pharmacist-led study

BackgroundDrug-drug interaction alters the efficacy of the drugs. Early identification can reduce unintended therapeutic outcomes. ObjectiveThe main objective of the present study was to assess the drug-drug interactions among patients with psychiatric disorders. MethodologyA prospective observational study was conducted for a period of eight months. A total of 112 psychiatric inpatients were enrolled in the study. The patients were monitored regularly to identify the incidence of potential and actual drug-drug interactions. The identified interactions were analyzed for their severity by using various standard references which included published scientific articles, online databases (e.g., UpToDate) and standard textbooks. Results and DiscussionThe mean age of the study population in years was found to be 37.93 ± 12.21 standard deviation. It was observed that the incidence of potential drug-drug interactions was 66.96%. A total of 201 potential drug-drug interactions were identified from 75 patients. Based on the severity assessment of the identified interactions, 52.73% were major, 37.31% were moderate, and 19.82% were minor. About 7.46% were contraindicated drug combinations. The data on the onset of interaction revealed that 34.82% were of delayed onset and 14.92% with rapid onset and 50.24% were not specified. The drug that was responsible for the majority of the interactions in the study was found to be olanzapine. ConclusionThe study revealed a high incidence of drug-drug interaction. Drug-drug interactions most frequently encountered among psychiatric patients were found to be major in terms of severity. The study concluded on the higher event of drug-drug interactions among the patients prescribed with olanzapine.

Prevalence of Potential Drug-Drug Interaction Risk among Chronic Kidney Disease Patients in a Spanish Hospital.

Chronic kidney disease (CKD) is a major health problem worldwide and, in Spain, it is present in 15.1% of individuals. CKD is frequently associated with some comorbidities and patients need to be prescribed multiple medications. Polypharmacy increases the risk of adverse drug reactions (ADRs). There are no published studies evaluating the prevalence of potential drug–drug interactions (pDDIs) among CKD patients in any European country. This study was aimed to determine the prevalence, pattern, and factors associated with pDDIs among CKD patients using a drug interactions program. An observational cross-sectional study was carried out at Plasencia Hospital, located in Spain. Data were collected among patients with CKD diagnoses and pDDIs were assessed by the Lexicomp® Drug Interactions platform. Data were obtained from 112 CKD patients. A total number of 957 prescribed medications were acknowledged, and 928 pDDIs were identified in 91% of patients. Age and concomitant drugs were significantly associated with the number of pDDIs (p < 0.05). According to the results, the use of programs for the determination of pDDIs (such as Lexicomp®) is recommended in the clinical practice of CKD patients in order to avoid serious adverse effects, as is paying attention to contraindicated drug combinations.

ERROS DE PRESCRIÇÃO DE MEDICAMENTOS NA ATENÇÃO PRIMÁRIA FRENTE AO PROGRAMA NACIONAL DE SEGURANÇA DO PACIENTE

Erros de prescrição podem provocar riscos de dano ao paciente, além de gastos desnecessários ao paciente e ao sistema público de saúde. O objetivo deste estudo foi realizar revisão da literatura sobre os erros de prescrição na atenção primária à saúde frente ao Programa Nacional de Segurança do Paciente. Trata-se de estudo de revisão da literatura cuja estratégia de busca foi pesquisa por artigos brasileiros publicados no período de 2013 a 2018, período de vigência do Programa Nacional de Segurança do Paciente, utilizando os descritores prescrição de medicamentos, erros de medicação e atenção primária à saúde. Os erros mais frequentes foram omissão da duração do tratamento, medicamentos prescritos por nome comercial, falta de adesão à Relação Nacional de Medicamentos Essenciais, polifarmácia com interações medicamentosas potenciais, terapia duplicada e combinações contraindicadas de medicamentos. Ainda são escassos os estudos que investigam erros relacionados a prescrição de medicamentos no âmbito da atenção primária à saúde. Outrossim, apesar da existência de legislação que regula ações voltadas à segurança do paciente no Brasil, é necessária a sensibilização por parte dos profi ssionais de saúde e gerenciamento quanto ao cumprimento da legislação, o que pressupõe a necessidade de expansão dos Núcleos de Segurança do Paciente para o âmbito da Atenção Primária à Saúde.

Rational use of antibiotics in an intensive care unit: a retrospective study of the impact on clinical outcomes and mortality rate.

BackgroundIntensive care units (ICUs) are specialized units where patients with critical conditions are admitted for getting specialized and individualized medical treatment. High mortality rates have been observed in ICUs, but the exact reason and factors affecting the mortality rates have not yet been studied in the local population in Pakistan.AimThis study was aimed to determine rational use of antibiotic therapy in ICU patients and its impact on clinical outcomes and mortality rate.MethodsThis was a retrospective, longitudinal (cohort) study including 100 patients in the ICU of the largest tertiary care hospital of the capital city of Pakistan.ResultsIt was observed that empiric antibiotic therapy was initiated in 68% of patients, while culture sensitivity test was conducted for only 19% of patients. Thirty-percent of patients developed nosocomial infections and empiric antibiotic therapy was not initiated for those patients (P<0.05). Irrational antibiotic prescribing was observed in 86% of patients, and among them, 96.5% mortality was observed (P<0.05). The overall mortality rate was 83%; even higher mortality rates were observed in patients on a ventilator, patients with serious drug–drug interactions, and patients prescribed with irrational antibiotics or nephrotoxic drugs. Adverse clinical outcomes leading to death were observed to be significantly associated (P<0.05) with irrational antibiotic prescribing, nonadjustment of doses of nephrotoxic drugs, use of steroids, and major drug–drug interactions.ConclusionIt was concluded that empiric antibiotic therapy is beneficial in patients and leads to a reduction in the mortality rate. Factors including irrational antibiotic selection, prescribing contraindicated drug combinations, and use of nephrotoxic drugs were associated with high mortality rate and poor clinical outcomes.

Prevalence and predictors of potential drug–drug interactions in patients of internal medicine wards of a tertiary care hospital in India

BackgroundDrug–drug interactions are a major source of adverse drug events (ADEs). Polypharmacy, age and the number of comorbid conditions are important predictors of adverse drug interactions. ADEs account for up...

Polypharmacy in the elderly.

Objective:The objective was to assess the frequency of polypharmacy and potential complications among local seniors.Methods:A cross-sectional convenience sample of 59 adults aged above 65 years was interviewed at Cuyahoga county (U.S. state of Ohio) senior programs. Polypharmacy was defined as more than five prescribed medications. Primary outcomes were frequent missed doses, one or more duplicate drug/s, and equal or more than one contraindicated drug combinations.Findings:Among seniors with the mean age of 76.9 years (25.4% male), 40.6% used multiple pharmacies and 35.6% had polypharmacy. Of all seniors with polypharmacy, about 57% had contraindicated drug combinations. Polypharmacy was associated with duplication (P = 0.02), but not frequent missed doses (P = 0.20).Conclusion:As shown by this study, polypharmacy was associated with duplicated therapy and contraindicated drug combinations. Improved communications among seniors, physicians, and pharmacists is necessary to minimize adverse consequences of polypharmacy.

Incidence of Antiretroviral Drug Interactions During Hospital Course: The Role of a Pharmacist-Led Antiretroviral Stewardship Program.

Background: Human immunodeficiency virus (HIV) providers are treating more comorbid conditions with additional pharmacologic agents, resulting in patients with HIV being disproportionately at risk for clinically significant drug-drug interactions (CSDDIs). There is a potential to overlook these interactions and ultimately place patients at risk for drug toxicity, resistance, and virologic failure. Objective: To assess the burden of CSDDIs among patients receiving antiretroviral therapy (ART) within 24 hours of admission and to evaluate the effect of a clinical pharmacist operating through an antiretroviral stewardship (ARVSP) program in identifying and correcting potential drug interactions. Methods: Adult HIV-positive patients receiving ART who were admitted to The Brooklyn Hospital Center from November 2010 through January 2012 were included in the analysis. Drug interactions were categorized according to time frame (ie, within 24 hours of admission vs after 24 hours of admission) and type (ie, contraindicated combinations, dosage modifications, and frequency alterations). The Liverpool HIV drug reference, Micromedex drug database, and the Department of Health and Human Services Guidelines were used as comprehensive tools for identification of antiretroviral drug errors. Results: Eighty-four CSDDIs were identified from 252 admissions among 158 patients receiving ART during the study period. Of the identified CSDDIs, 61 (73%) occurred within 24 hours of admission and 23 (27%) later in the hospital course. Forty-eight drug interactions (57%) represented contraindicated drug combinations. Protease inhibitor-based regimens were associated with the highest percentage of CSDDIs (98%). Of all CSDDIs, the most common interacting drug class was acid-suppressive therapy (63%). Clinical pharmacists identified and intervened in 80% of the CSDDIs that occurred on patient admission with all interventions accepted. Conclusions: CSDDIs are common among patients receiving ART at the time of admission and throughout the hospital course. Interventions including medication review by clinical pharmacists are critical in the prevention of CSDDIs on admission.

Drug-Drug Interactions in the Hematology and Oncology Department: A Real-Life Assessment of Frequency and Severity

Abstract 4250 Introduction:Drug-drug interactions (DDI) may lead to adverse drug events and constitute a risk for patients and a major challenge for treating physicians. Especially cancer patients receive a considerable number of concomitant drugs for the treatment of the underlying disease, the side effects of cancer therapy and due to preexisting comorbidities. As more and more older and severely compromised patients are treated today, polypharmacy and its related problems are of growing importance. However, data on the frequency and nature of DDI in cancer patients during hospitalization are rare. Methods:To determine the prevalence and nature of potential DDI, we performed a detailed chart review of all hospitalized patients in our hematology and oncology department during two randomly appointed days. All medications administered on these very days were extracted from the electronically archived patients' medical charts. DDI were identified and rated for severity and level of evidence using two different electronic interaction databases, Micromedex 2.0 and Lexi-Interact. Only DDI of at least moderate severity (i.e. rated as moderate, major or contraindicated) were included in the analysis, and documented irrespective of their actual clinical consequences. At the time of analysis, no routinely performed DDI screening or electronic DDI alert system was in place in our department. Results:Medication profiles from 157 inpatients were analyzed. Patients’ median age was 62 years (range: 25–94). Underlying diseases were leukemia (n=51), lymphoma (n=49), solid tumors (n=49) and non-malignant diseases (n=8). We evaluated a total of 1748 drug prescriptions with a median of 11 drugs per patient and day (range: 1–22). The median number of drugs was 9 in patients with solid tumors, 11 in patients with leukemia, and 12 in patients with lymphoma or non-malignant diseases. We found a total of 1153 drug interactions rated as of at least moderate severity by either Micromedex or Lexi-Interact, which corresponds to 734 DDI/100 patient days. The drug classes most frequently involved comprised antibiotics (23%), antifungals (21%), diuretics (20%), corticosteroids (17%), calcium channel blockers (11%), immunosuppressants (10%), benzodiazepines (9%) and opioid analgesics (8%). Antineoplastic drugs constituted 2.7% of all prescribed drugs, and were involved in 47 DDI (4%). The severity rating for all DDI was contraindicated, major and moderate in 2%, 24% and 74% of cases, respectively, according to the respective higher rating of both databases. The median number of DDI per patient was 5 (range: 0–31), and was highest for patients with leukemia with a median number of 7. 85% of patients experienced at least one DDI, and 26% of patients were exposed to ≥10 DDI on the evaluated day. The level of evidence of the 1153 DDI identified was excellent, good, fair and poor in 10%, 45%, 44% and 1% of cases, respectively.To identify the most clinically relevant DDI, we also determined the frequency and nature of those DDI which were rated as major severity or contraindicated by both databases. 61 DDI fulfilled these criteria and occurred in 33/157 patients (21%). The level of evidence of those 61 DDI was excellent, good and fair in 18%, 28% and 54% of cases, respectively. The most frequently detected potential clinical consequences of the 61 DDI rated as major or contraindicated by both databases were QT-prolongation with a variety of drug combinations (n=36), extrapyramidal reactions of different combinations including metoclopramide (n=5), and cyclosporine toxicity in combination with voriconazole (n=4). Conclusions:This retrospective DDI analysis revealed a high percentage of patients encountering DDI, including contraindicated drug combinations. Although some of these DDI are difficult to avoid or well manageable through close monitoring of the patients' clinical condition or laboratory results, there is a strong need for rising awareness of DDI to avoid patient harm. This is of particular relevance in the hematology and oncology setting, where numerous drugs are being applied, including cytotoxic agents. By identifying the most relevant DDI in this setting, these results allow targeted physician education and highlight the need to implement an electronic prescription system with DDI alerts in close cooperation with clinical pharmacists. Disclosures:No relevant conflicts of interest to declare.

Evaluation of Contraindicated Drug-Drug Interaction Alerts in a Hospital Setting

Risks associated with contraindicated drug-drug interaction alerts (CDDIAs) should always outweigh benefits. Misclassified CDDIAs should be eliminated. To review CDDIAs and determine if they are contraindicated according to Food and Drug Administration-approved product labeling and if there are circumstances in which contraindicated interactions are acceptable. A cross-sectional observational and quality improvement study was conducted over two 1-year periods. The 20 most common CDDIAs from May 2007 to May 2008 and all CDDIAs from April 2008 to April 2009 were collected at a large teaching hospital. Horizon Meds Manager used First DataBank as the knowledge base for decision support. Interactions were deemed truly contraindicated if listed in the contraindications section of the labeling of at least one of the interacting drugs. Alerts were grouped by drug and pharmacologic class to evaluate the evidence supporting the relevance of these interactions. An expert panel determined when an alert was misclassified. A medical advisory committee determined whether a contraindicated drug-drug combination was acceptable. Twelve (60%) of the most common 20 contraindicated interaction pairs from 2007 to 2008 were inappropriately classified. Half of the alerts were not truly contraindicated. The 8 truly contraindicated drug-drug pairs were ketorolac and other nonsteroidal antiinflammatory drugs or oral solid potassium products and anticholinergics. Half of these interactions were subsequently deemed acceptable under specific circumstances. Similar results were found in the second year, with only 55.1% of all CDDIAs being truly contraindicated despite eliminating some of the alerts that were misclassified in the first year. Nearly three fourths of legitimate CDDIAs were deemed acceptable under specific circumstances. Most contraindicated drug-drug interaction alerts from a commercial knowledge base were inappropriately categorized and could be downgraded. Some contraindicated drug combinations are permissible under specific circumstances. Alerts suggesting that certain drugs should never be used together, but their use together is sometimes acceptable, contribute to alert fatigue.

Deaths involving contraindicated and inappropriate combinations of serotonergic drugs

In the Australian state of Victoria, all fatalities that were recorded from 2002 through to 2008 involving the use of certain serotonin active drugs (tramadol, venlafaxine, fluoxetine, sertraline, citalopram and paroxetine), were reviewed to assess the incidence of contraindicated or ill advised drug combinations. More than 1,000 were identified of which 326 cases formed the basis of this study. These cases involved contraindicated or inappropriate drug combinations that can lead to adverse drug reactions (ADRs) and subsequent fatal toxicity. Of these, 46% were drug-related, 35% were a result of natural disease and 13% were classified as external injury cases. The remaining cases were those where the cause of death (COD) was unascertained. Tramadol was the most common drug, usually detected alongside a serotonergic antidepressant (in 20% of cases). Twenty-five (8%) cases involved contraindicated drug combinations while the remainder (301 cases, 92%) involved drug combinations that are associated with adverse interactions ranging from minor to major severity. Of these 326 cases, the Coroner determined 166 cases (51%) to be acts of intentional self-harm or drug misuse, with the remainder unascertained or attributed to natural disease. Very few post-mortem reports and Coroners' findings made mention of possible ADRs when such combinations were actually present. The majority of cases comprising contraindicated drug combinations involved the combined use of five drugs (24%) at the time of death. A combination of three to five drugs was most common in cases involving inadvisable drug combinations. Combined drug toxicity was the most common COD, with heart disease the most common co-morbidity.

Results from a mailed promotion of medication reviews among Department of Defense beneficiaries receiving 10 or more chronic medications.

Like many payers, the Department of Defense (DoD) has limited ability to work directly with prescribers to ensure appropriate medication use. Many older beneficiaries are prescribed multiple maintenance medications, placing them at higher risk for adverse drug interactions, contraindicated medication use, and other polypharmacy-related problems. Medication reviews may mitigate these risks, but the optimal venue for medication therapy management is unclear. To (a) determine if beneficiaries will respond to a mailed request from the DoD to pursue a medication review; (b) identify medication review location and outcomes from the patient perspective; and (c) assess the statistical significance of changes in the number of prescription medications overall and for key categories, including maintenance medications and contraindicated medications, relative to a propensity-matched comparison group. A total of 4,000 TRICARE beneficiaries aged 55 years or older, residing in North Carolina, who obtained 10 or more maintenance medications (defined by a unique combination of drug, strength, and dosage form) during the 90-day baseline period from May 3, 2008, to July 31, 2008, were mailed letters requesting their participation in the study. Consenting subjects received a personalized medication list to review with their physicians or pharmacists and a survey form to complete after the review. Survey results were compared by location of medication review (i.e., physician's office, pharmacy, or both). Changes from the 90-day baseline to 90-day post-intervention period were calculated for prescription utilization measures (total drug count, maintenance drug count, count of Beers list medications, and count of contraindicated drug combinations) for the subsample of subjects who completed the survey (n = 373) and for subjects who received the initial consent letter (n = 3,856) versus a propensity-matched comparison sample drawn from neighboring states. Variables included in the propensity score were gender, age group, military rank, catchment status indicating proximity to military pharmacies, enrollment status, number of pharmacy settings used, and each of 30 binary disease indicators. A total of 1,469 subjects responded to the consent letter (response rate = 38.1%); 606 subjects consented to participate (consent rate = 15.7%); and 373 subjects returned a completed survey (completion rate = 9.7%). Among those who completed the survey, 190 (50.9%) received reviews in a physician's office; 103 (27.6%) received reviews in a pharmacy; 60 (16.1%) received reviews in both locations; and 20 (5.4%) reported a different location or no location. 61 survey respondents (16.4%) indicated that they were told to stop a medication, and 77 (20.6%) reported a dosage change. Medication changes occurred significantly more frequently for reviews performed at a physician's office compared with other review locations. Therapeutic classes most frequently stopped or adjusted for dosage were antidiabetics, diuretics, antilipidemics, renin-angiotensin aldosterone system inhibitors, anticoagulants, nonsteroidal anti-inflammatory drugs, and beta-adrenergic blocking agents. 85% of respondents reported that the medication review was worth doing. In the assessments of changes in prescription utilization from the baseline to post-intervention periods, no significant by-group differences were noted among those who completed the study relative to their matched comparison subjects. In the comparison of subjects who received the initial consent letter with their matched counterparts, small but statistically significant differences were observed for several prescription utilization measures, including changes in use of high-risk Beers list medications (P = 0.033); use of electrolytic, caloric, and water balance medications (P = 0.038); and use of hypertension medications (P = 0.028). The magnitude of the decrease observed among comparison subjects, however, exceeded that observed among the case subjects. Response was poor to a mailing that promoted a beneficiary- initiated medication review. The absence of significant changes following the medication review suggests several possibilities: a mailed intervention is ineffective in promoting medication review; medication regimens for study subjects are already optimized to the extent obtainable through a routine medication review; or the study sample size was too small to detect relevant changes. Most drug regimen changes were dosage adjustments for current medications or substitutions within the same therapeutic class. The extent to which comprehensive assessment of a patient's medication regimen, including nonprescription and herbal agents, was performed is unclear. More intensive interventions may be required to ensure that medication regimens are being actively managed among those who use a large number of prescription medications.

Black Box Warning Contraindicated Comedications: Concordance Among Three Major Drug Interaction Screening Programs

Black box warnings represent the strongest safety warning that the Food and Drug Administration can issue for a marketed prescription drug. Some black box warnings recommend against coadministration of specific medications due to an increased risk for serious, perhaps life-threatening, effects. To determine the level of agreement in presence, clinical severity scores level of documentation ratings, and alert content among 3 leading drug interaction screening programs with regard to contraindicated comedications that are mentioned in black box warnings. We reviewed the prescribing information for currently marketed prescription drugs with a black box warning that mentioned a contraindicated drug combination. We selected the drug interaction databases Facts & Comparisons 4.0, MICROMEDEX DRUG-REAX, and Lexi-Comp Lexi-Interact to evaluate the interactions. Discrepancies in the inclusion of interactions and level of agreement in clinical severity scores and level of documentation ratings for each interaction were assessed, using descriptive statistics, Spearman's correlation coefficient, Kendall-Stuart tau-c, and Cronbach's alpha. We identified 11 drugs with black box warnings that contained information on 59 unique contraindicated drug combinations, only 68% of which were covered by any source. Lexi-Comp detected the most interactions (n = 29) and DRUG-REAX the least (n = 18). Only 3 drug combinations were detected and rated as contraindicated or potentially life-threatening in all 3 databases. The severity scores and level of documentation ratings varied widely. There are discrepancies among major drug interaction screening programs in the inclusion, severity, and level of documentation of contraindicated drug combinations mentioned in black box warnings. Further studies could explore the implications of these inconsistencies, particularly with regard to the integration of black box warning information in clinical practice. Clinicians should consult multiple drug resources to maximize the potential for detecting a potentially severe drug interaction.

Incidence and Possible Causes of Prescribing Potentially Hazardous/Contraindicated Drug Combinations in General Practice

Preventing the use of medications where there is the potential for serious drug-drug interactions or drug-disease interactions (contraindications) is essential to ensure patient safety. Previous studies have looked at the incidence of prescribing contraindicated drug combinations, but little is known about the underlying reasons for the co-prescribing events. The objectives of this study were to estimate the incidence of prescribing contraindicated drug combinations in general practice and to explore the clinical context, possible causes and potential systems failures leading to their occurrence. A list of contraindicated drug combinations was compiled according to established references. A search of computerised patient medication records was performed, followed by detailed chart review and assessment. The patient records from four general practices in an area of England were searched for a period of 1 year (1 June 1999-31 May 2000) to identify contraindicated drug combinations. All patients registered with the four participating practices during the study period were included (estimated n = 37 940). Medical records of the cases identified by the computer search were reviewed in detail and relevant information was extracted. Each case was then independently assessed by a pharmacist and a physician who judged whether the co-prescribing was justified and whether it was associated with an adverse drug event. Proximal causes and potential systems failures were suggested for each co-prescribing event. Fourteen patients with potential drug-drug interactions and 50 patients with potential drug-disease interactions were identified. Overall, these represent an incidence of 1.9 per 1000 patient-years (95% CI 1.5, 2.3) or 4.3 per 1000 patients being concurrently prescribed > or =2 drugs per year (95% CI 3.2, 5.4). 62 cases involving 63 co-prescribing events were reviewed. Two-thirds of these events involved medications that were initiated by hospital doctors. Awareness of the potential drug-drug or drug-disease interactions was documented in one-third of the events at the time of initial co-prescribing. Within the study period, the co-prescribing was judged to be not justified in 44 events (70%). Potential drug-drug interactions possibly resulted in two adverse drug events. The majority of contraindicated co-prescribing related to drug-disease interactions involved the use of propranolol or timolol eye drops for patients receiving bronchodilators and the use of amiodarone for patients receiving levothyroxine sodium. The prescribing of contraindicated drug combinations was relatively rare in this study. Multiple possible causes and systems failures were identified and could be used to develop strategies for the prevention of prescribing errors involving contraindicated drug combinations in primary care.

注射薬を含めた相互作用チェックシステムによる併用禁忌の解析―薬歴の中での相互作用チェックの重要性

In order to avoid adverse drug-interactions, we improved a computerized check system incorporated in the physician order-entry system. The improved system checks all drugs prescribed for a patient, including injections, and does not allow contraindicated combinations of drugs to be used. Our system also has a function for recommending safer substitutions for contraindicated drugs. In cases where contraindicated combinations are unavoidable, physicians may prescribe them by entering a password that is valid for one day only. The improved system can also evaluate the kinds of contraindicated combinations that physicians intend to prescribe. On checking our system's database, we found that there had been 299 contraindication alerts during 13 months for 589, 973 prescriptions. Also, the incidence of attempts to prescribe contraindicated drugs after clinical hours was almost 4 times as high as that during clinical hours. The contraindicated drug combinations were found in more than one type of prescription. Surprisingly, 80% of contraindicated combination events involved in injections and more than a half of contraindicated combinations were oral medicines with injections. We released alerts when requested by physicians when we judged these requests to be reasonable and 77 alerts were released during the 13-month period.Thus, our computerized system, which checks drugs as physicians enter orders for them, should be extremely useful in ensuring medication safety. Our findings indicate the possibility that pharmacists are often unaware of the contraindicated combinations after physicians have ordered prescriptions, and also the desirability of pharmacists verifying drug interactions in patient medication histories.

Pharmaceutical Care: Impact on Asthma Medication Use

Background: Asthma has been recognised as a poorly managed disease state in Australia. Rural areas have been identified as being under‐serviced by health professionals. Pharmacists in rural areas are in a prime position to be involved in the provision of multidisciplinary asthma care.Aim: This study investigated the impact of spirometry screening on asthma management by pharmacists in rural areas.Method: A two‐group (intervention: n = 141, control: n = 46) multicentre study design was utilised. The control group was provided with a standard medication review while the intervention group received spirometry testing and a medication review. The study protocol required pharmacists to refer participants to a doctor if required, based on spirometry or medication review results. The researchers assessed asthma severity and adequacy of asthma medication.Results: Spirometry as an intervention attracted participants to the study pharmacies and provided an opportunity for pharmacists to screen and refer a group who may otherwise be overlooked. Medication review identified suboptimal therapy, potentially contraindicated drug combinations and adverse drug reactions.Conclusion: Spirometry adds benefit to the provision of pharmaceutical care for people with asthma. This may have additional significance in rural areas where access to other health services is limited.

Using information systems technology to improve antibiotic prescribing.

The selection of antimicrobial agents in the hospital setting is still a largely manual task and, therefore, fraught with the potential for error. This includes the choice of agents, dosage regimens, and monitoring for response and toxicity. The authors describe current and future strategies to use information technology to improve the process of antimicrobial selection and to avoid dosing errors and contraindicated drug combinations. The possible role of decision support in preventing the emergence of resistance is also discussed.

Impact of a Web-based clinical information system on cisapride drug interactions and patient safety.

Most commercially available drug-interaction screening systems have important limitations that fail to protect patients from dangerous drug combinations. We attempted to overcome the limitations of our commercial program by developing a Web-based clinical information system to serve as a safety net. This system identifies drug interactions with newly marketed medications not screened by our commercial program, and generates a second alert on dangerous interactions that were overridden during order processing. The Web-based system uses patient-specific pharmacy, laboratory, and demographic data to generate detailed alerts on patients receiving potentially dangerous drug combinations. The system's impact on the use of dangerous drug combinations and related adverse events was evaluated by a retrospective analysis of patients receiving cisapride with contraindicated medications in the 2 years before and after implementation. The rate of dangerous drug combinations declined by 66% after implementing the system, from 9.0% of cisapride orders in 1994 and 1995 to 3.1% in 1996 and 1997 (P<.001). The mean [SD] duration of contraindicated therapy (4.1 [3.8] vs 1.6 [1.4] days, P<.001) and proportion of patients being discharged under treatment with a dangerous drug combination (36.2% vs 7.7%, P<.001) was also significantly reduced during the study period. Three patients (1.7%) during the control period experienced serious adverse events that may have been related to the targeted drug interactions. No symptomatic cardiac events were identified during the study period (P = .21). An automated system running as a safety net can be an efficient method of detecting contraindicated drug combinations and serves an important role in the avoidance of potentially serious adverse drug events.