Search

Identifying drug-drug interactions (DDIs) is a major challenge in drug development. Previous attempts have established formal approaches for pharmacokinetic (PK) DDIs, but there is not a feasible solution for pharmacodynamic (PD) DDIs because the endpoint is often a serious adverse event rather than a measurable change in drug concentration. Here, we developed a metric ''S-score'' that measures the strength of network connection between drug targets to predict PD DDIs. Utilizing known PD DDIs as golden standard positives (GSPs), we observed a significant correlation between S-score and the likelihood a PD DDI occurs. Our prediction was robust and surpassed existing methods as validated by two independent GSPs. Analysis of clinical side effect data suggested that the drugs having predicted DDIs have similar side effects. We further incorporated this clinical side effects evidence with S-score to increase the prediction specificity and sensitivity through a Bayesian probabilistic model. We have predicted 9,626 potential PD DDIs at the accuracy of 82% and the recall of 62%. Importantly, our algorithm provided opportunities for better understanding the potential molecular mechanisms or physiological effects underlying DDIs, as illustrated by the case studies. [ABSTRACT FROM AUTHOR]

Background: Causality assessment is used to determine the likelihood that a drug caused a particular adverse event. There are multiple methods for assessing the causality of suspected adverse drug reactions (ADRs). Undertaking some form of causality assessment of suspected ADRs is part of pharmacovigilance practice, but potentially without value if reproducibility of the results is consistently poor, and may vary with the background and experience of the assessor. Objective: The aim of this study was to compare inter-assessor agreements for causality assessment of epidemiological study data from an individual perspective and between individuals from different healthcare backgrounds. Study Methods: Six assessors (two pharmacists, two physicians and two nurses), assessed 200 ADR reports for causality using the Naranjo ADR Probability Scale, the Venulet algorithm and the WHO causality term assessment criteria. Agreement between assessors using the same algorithms was examined, and agreement between the algorithms for the same assessor was also measured. Results: For all methods, the majority of the causality assessments resulted in 'probable' or 'possible' categorization. Physician and pharmacist assessment was more likely to result in 'definite' or 'certain" causality assessments than nurse assessment, when using the Naranjo and WHO algorithms. Use of the Venulet algorithm resulted in a higher number of 'unlikely' or 'unrelated' assessments than the other two methods. The inter-assessor agreement measured was no greater than 'fair' (weighted kappa [κw] = 0.31 ) for any comparison between raters, and for three comparisons, inter-assessor agreement was less than that expected by chance. Conversely, the weighted observed proportion of agreement, Po (w), was good (>0.6) for all assessments. Intra-assessor agreement between scales was highest for the Naranjo algorithm versus the WHO algorithm, with 'substantial" (κw = 0.61) agreement between assessments made by pharmacist 1. The lowest level of agreement within assessors came from nurse 2 when comparing the Naranjo and Venulet algorithms, where agreement was 'slight' (κw = 0.19), though the mean Po (w) for intra-assessor agreement was 0.81. Conclusions: Comparability between assessors was found to be "fair' or less for the ADR causality assessment methods examined in this study. The most consistent results were produced by the application of the Naranjo algorithm and the least consistent was the Venulet algorithm. It is likely that the clinical experience of the assessor influences how the assessment methods are applied. The high level of disagreement in the results produced using the assessment scales in this study question the robustness of causality assessments. [ABSTRACT FROM AUTHOR]

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT ADRs in hospital patients are a significant burden, though how often ADRs cause re-admission to hospital has not been well documented in the literature. WHAT THIS STUDY ADDS • One fifth of patients re-admitted to hospital within 1 year of discharge from their index admission were re-admitted due to an adverse drug reaction. • Admission to a medical ward, elderly age and prescription of anti-platelet agents or diuretics were identified as risk factors for re-admission due to ADRs. • Since up to 50% of these reactions were possibly avoidable, better methods of medication review in both hospital and primary care, in conjunction with a clinical review, are needed to enable improved prescribing practices that will be essential for improving the benefit-harm balance of medicines. AIM The proportion of re-admissions to hospital caused by ADRs is poorly documented in the UK. The aim of this study was to evaluate the impact of ADRs on re-admission to hospital after a period as an inpatient. METHODS One thousand patients consecutively admitted to 12 wards were included. All subsequent admissions for this cohort within 1 year of discharge from the index admission were retrospectively reviewed. RESULTS Of the 1000 patients included, 403 (40.3%, 95% CI 39.1, 45.4%) were re-admitted within 1 year. Complete data were available for 290 (70.2%) re-admitted patients, with an ADR contributing to admission in 60 (20.8%, 95% CI 16.4, 25.6%) patients. Presence of an ADR in the index admission did not predict for an ADR-related re-admission (10.5% vs. 7.2%, P = 0.25), or re-admission overall (47.2% vs. 41.2%, P = 0.15). The implicated drug was commenced in the index admission in 33/148 (22.3%) instances, with 37/148 (25%) commenced elsewhere since the index admission. Increasing age and an index admission in a medical ward were associated with a higher incidence of re-admission ADR. The most frequent causative drugs were anti-platelets and loop diuretics, with bleeding and renal impairment the most frequent ADRs. Over half (52/91, 57.1%) of the ADRs were judged to be definitely or possibly avoidable. CONCLUSIONS One fifth of patients re-admitted to hospital within 1 year of discharge from their index admission are re-admitted due to an ADR. Our data highlight drug and patient groups where interventions are needed to reduce the incidence of ADRs leading to re-admission. [ABSTRACT FROM AUTHOR]

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Adverse drug reactions (ADRs) are a reporting category in the National Patient Safety Agency (NPSA) incident reporting system, though the Medicines and Healthcare Products Regulatory Agency (MHRA) pharmacovigilance system is the more established method for collecting ADR data. WHAT THIS STUDY ADDS • The majority of ADRs were shown to be of moderate risk to the patient, though some have a severe or catastrophic impact. Classification and reporting of ADRs according to NPSA guidance is possible but offers limited additional value to efforts to improve patient safety over and above the Yellow Card Scheme. AIM In the UK, the National Patient Safety Agency (NPSA) includes adverse drug reactions as a reporting category, while the MHRA Yellow Card Scheme also collects data regarding adverse drug reactions (ADRs). In this study, we aimed to assess ADRs using NPSA criteria and discuss the resulting implications. METHODS ADRs identified in a 6-month prospective study of 3695 inpatient episodes were assessed according to their impact on the patient and on the organization, using tools developed by the NPSA. RESULTS Seven hundred and thirty-three (100%) ADRs were assessed. In terms of impact on the patient, 537 (73.3%) were categorized as ‘low’ (minor treatment), 181 (24.7%) as ‘moderate’ (moderate increase in treatment, no permanent harm), 14 (1.91%) as ‘severe’ (permanent harm) and 1 (0.14%) was categorized as ‘catastrophic’ (direct cause of death). In terms of impact on the organization, none was categorized as ‘no harm/ no risk’, 508 (69.3%) as ‘insignificant’, 188 (25.6%) as ‘minor’, 25 (3.4%) as ‘moderate’, 12 (1.6%) as ‘major’ and none was classed as ‘catastrophic’. Less than 2% of ADRs would be eligible for detailed analysis according to the NPSA guidance. The ADRs that cause incidents of greater significance relate to bleeding, renal impairment and Clostridium difficile infection. CONCLUSIONS Classification of ADRs according to NPSA guidance offers limited additional value over and above that offered by the Yellow Card System. A consistent message needs to be sent to prospective reporters of ADRs; the availability of more than one system is likely to confuse reporters and does not aid patient safety. [ABSTRACT FROM AUTHOR]

Adverse drug reactions (ADRs) are a major cause of hospital admissions, but recent data on the incidence and clinical characteristics of ADRs which occur following hospital admission, are lacking. Patients admitted to twelve wards over a sixmonth period in 2005 were assessed for ADRs throughout their admission. Suspected ADRs were recorded and analysed for causality, severity and avoidability and whether they increased the length of stay. Multivariable analysis was undertaken to identify the risk factors for ADRs. The 5% significance level was used when assessing factors for inclusion in multivariable models. Out of the 3695 patient episodes assessed for ADRs, 545 (14.7%, 95% CI 13.6-15.9%) experienced one or more ADRs. Half of ADRs were definitely or possibly avoidable. The patients experiencing ADRs were more likely to be older, female, taking a larger number of medicines, and had a longer length of stay than those without ADRs. However, the only significant predictor of ADRs, from the multivariable analysis of a representative sample of patients, was the number of medicines taken by the patient with each additional medication multiplying the hazard of an ADR episode by 1.14 (95% CI 1.09, 1.20). ADRs directly increased length of stay in 147 (26.8%) patients. The drugs most frequently associated with ADRs were diuretics, opioid analgesics, and anticoagulants. In conclusion, approximately one in seven hospital in-patients experience an ADR, which is a significant cause of morbidity, increasing the length of stay of patients by an average of 0.25 days/patient admission episode. The overall burden of ADRs on hospitals is high, and effective intervention strategies are urgently needed to reduce this burden. [ABSTRACT FROM AUTHOR]

Aims To investigate the attitudes of UK hospital pharmacists towards, and their understanding, of adverse drug reaction (ADR) reporting. Methods A postal questionnaire survey of 600 randomly selected hospital pharmacists was conducted. Results The response rate was 53.7% (n = 322). A total of 217 Yellow Cards had been submitted to the CSM/MCA by 78 (25.6%) of those responding. Half of those responding felt that ADR reporting should be compulsory and over three-quarters felt it was a professional obligation. However, almost half were unclear as to what should be reported, while the time available in clinical practice and time taken to complete forms were deemed to be major deterrents to reporting. Pharmacists were not dissuaded from reporting by the need to consult a medical colleague or by the absence of a fee. Education and training had a significant influence on pharmacists' participation in the Yellow Card Scheme. Conclusions Pharmacists have a reasonable knowledge and are supportive of the Yellow Card spontaneous ADR reporting scheme. However, education and training will be important in maintaining and increasing ADR reports from pharmacists. [ABSTRACT FROM AUTHOR]