Pharmacoepidemiologic study of potential drug interactions in outpatients of a university hospital in Thailand

The Prevalence and Severity of Potential Drug-Drug Interactions in Internal Medicine Ward at Soba Teaching Hospital

Background

Multiple drug therapies are commonly used to achieve a desired therapeutic goal, especially in hospitalized patients. However, drug-drug interactions might occur and threaten the patients' safety.

Objective

This study aims to assess the prevalence and severity of potential drug-drug interactions (PDDIs) in the internal medicine ward at Soba Teaching Hospital.

Methods

A retrospective cross-sectional hospital-based study was carried out in the internal medicine ward at Soba Teaching Hospital from June 2021 to December 2021. The data was collected from patients' medical records. PDDIs were identified using Lexicomp® drug interaction software.

Results

A total of 377 patients were included in this study, and overall prevalence of PDDIs was 62.9%. We have identified 989 potential DDIs and 345 pairs of interacting drugs, the mean of the PDDIs per patient was 4.17 ± 4.079. Among 345 PDDIs most were of moderate interactions 70.1% (n=242) followed by Minor interactions 19.1% (n=66). The most common type of interaction was of category C representing 63.5% (n=219). A significant association was observed between the occurrence of PDDIs with patients' age, presence of chronic diseases, length of hospital stay, and number of medications received by the patients.

Conclusion

Drug-drug interactions were highly prevalent in the internal medicine ward. Therefore, certain attempts are required to increase the awareness of the physicians about these interactions and minimize their occurrence.

Evaluation of medication errors in patients with kidney diseases in Quetta, Pakistan

BACKGROUND

Medication errors represent a significant challenge in healthcare, as they can lead to enduring harm for patients and impose substantial financial burdens on the healthcare system. To effectively mitigate medication errors, it is imperative to gain a comprehensive understanding of their frequency and the contributing variables. Thus, the primary objective of this study was to evaluate the occurrence of medication errors among patients with kidney diseases in Quetta, Pakistan.

METHODS

The objective of this study was to assess medication errors in patients diagnosed with kidney diseases in Quetta, Pakistan. The research was conducted at the Balochistan Institute of Nephro-Urology Quetta (BINUQ) Hospital, which serves as a tertiary care center specializing in the treatment of kidney diseases. A cross-sectional descriptive study design was employed over a period of six months. The study population consisted of patients admitted to the Nephro-urology wards at BINUQ Hospital during the specified duration. Data collection encompassed various methodologies, including checklist-guided observation, review of prescription order forms, documentation of drug administration, and comprehensive analysis of patient medical records. Descriptive and analytical analyses were conducted using SPSS version 23. Univariate analysis was employed to identify independent variables associated with medication errors, employing a significance level of p<0.01. The multivariate logistic regression analysis incorporated variables that exhibited a significant association with medication errors during the univariate analysis. Only those variables demonstrating a p-value of less than 0.05 at a 95% confidence level were considered significant predictors of medication administration errors within the final multivariate model.

RESULTS

Among the 274 medication errors identified in the study, documentation errors accounted for 118 cases (12.06%), administration errors for 97 cases (9.91%), prescribing errors for 34 cases (3.47%), and dispensing errors for 25 cases (2.55%). Statistical analysis revealed significant associations (p<0.05) between forgetfulness and duty shift, and medication errors in the documentation process. Similarly, inattention was significantly associated (p<0.05) with both prescribing and dispensing errors. Furthermore, the number of medications received emerged as the most influential factor associated with medication errors. Patients receiving 4-6 medications exhibited an odds ratio of 9.08 (p<0.001) compared to patients receiving 1-3 medications, while patients receiving more than 6 medications had an odds ratio of 4.23 (p<0.001) in relation to patients receiving 1-3 medications.

CONCLUSION

In conclusion, this study determined that documentation errors were the most prevalent medication errors observed in patients with kidney disease in Quetta, Pakistan. Forgetfulness and duty shift were associated with documentation errors, whereas inattention was linked to prescribing and dispensing errors. The significant risk factor for medication errors was found to be a high number of prescribed medications. Therefore, strategies aimed at reducing medication errors should prioritize enhancements in documentation practices, alleviating medication burden, and increasing awareness among healthcare providers.

Potential drug-drug interactions in adults receiving oral anticoagulant and antiaggregant therapy

BACKGROUND

Anticoagulant and antiaggregant drugs are drug groups with high mortality and the most common cause of malpractice.

RESEARCH DESIGN AND METHODS

18 and 65 years were scheduled for pharmacotherapy in the Family Health Center. 122 patients during their anticoagulant and/or antiaggregant treatment were evaluated in terms of drug-drug interactions.

RESULTS

Drug-drug interactions were detected in 89.7% of the patients included in the study. A total of 212 drug-drug interactions were found in 122 patients. Of these, 12 (5.6%) were identified as A, 16 (7.5%) B, 146 (68.6%) C, 32 (15.2%) D and 6 (2.8%) X risk category. The number of DDI was found to be significantly higher in patients aged between 56 and 65 years. The most drug interactions are significantly higher in the C and D categories, respectively. The most predicted clinical outcomes of DDI's were increased in the therapeutic effect and adverse/toxic reactions.

CONCLUSIONS

Contrary to expectations, it is seen that although polypharmacy is relatively less in patients aged 18-65 years compared to patients over 65 years of age, it is very important to detect drug interactions in this age group in terms of safety, efficacy and treatment benefit in terms of drug-drug interaction.

Assessment of risk factors associated with potential drug-drug interactions among patients suffering from chronic disorders

Patients suffering from chronic diseases are more likely to experience pDDIs due to older age, prolonged treatment, severe illness and greater number of prescribed drugs. The objective of the current study was to assess the prevalence of pDDIs and risk factors associated with occurrence of pDDIs in chronic disease patients attending outpatient clinics for regular check-ups. Patients suffering from diabetes, chronic obstructive pulmonary disease (COPD), stroke and osteoporosis were included in the study. This study was a cross sectional, observational, prospective study that included 337 patients from outpatient clinics of respiratory ward, cardiac ward and orthopedic ward of Nishter Hospital Multan, Pakistan. The mean number of interactions per patient was 1.68. A greater risk for occurrence of pDDI was associated with older age ≥ 60 years (OR = 1.95, 95% CI = 1.44-2.37, p<0.001); polypharmacy (≥ 5 drugs) (OR = 3.74, 95% CI 2.32-4.54, p<0.001); overburden (OR = 2.23, 95% CI = 1.64-3.16, p<0.01); CCI score (OR = 1.28, 95% CI = 1.04-1.84, p<0.001); multiple prescribers to one patient (OR = 1.18, 95% CI = 1.06-1.41, p<0.01); and trainee practitioner (OR = 1.09, 95% CI = 1.01-1.28, p<0.01). Old age, polypharmacy, overburden healthcare system, higher comorbidity index, multiple prescribers to one patient and trainee practitioner were associated with increased risk of occurrence of pDDIs in chronic disease patients.

A Survey of Medical Residents' Knowledge, Attitude, and Practice about Drug-Drug Interactions, Shiraz, Iran

Rationale, aims and objectives: Medical residents are among the most important and influential members of the medical team and the level of their knowledge regarding potential drug-drug interactions (DDIs) is a good predictor of the ability to prevent the occurrence of DDIs, as well as safe and rational prescribing in inpatient settings. This survey was designed to evaluate internal medicine and cardiology residents' knowledge and opinion toward DDIs and to determine different sources of DDI information used by this population. Method: This cross-sectional knowledge attitude practice (KAP) questionnaire study was conducted in Shiraz, Iran. A 25-question questionnaire was designed and completed by 86 internal medicine and cardiology residents. The questions were related to the participants' demographic information, their practice characteristics, the information sources used by the participants, the residents' opinion regarding DDIs, and their knowledge regarding the interaction between 8 drug pairs. Results: The results showed that when the participants wanted to learn more about DDIs, most of them used software on mobile or tablet (59.3%). Nearly three-fourths of the participants (73.82%) reported that when a patient was about to be exposed to a potential DDI, they were informed by software on mobile or tablet that the interaction may be present. On average, residents answered 44.03% ± 23.79 of drug pair questions correctly.Conclusion: Our results show insufficient practice skills, as well as relatively poor knowledge concerning the participants' answers to questions. It seems that further practical training and education are required to enable prescribers to prevent potential DDIs.

Associated factors of potential drug-drug interactions and drug-food interactions in patients with multiple sclerosis

Background:

Multiple sclerosis (MS) is the most common immune-mediated demyelinating disease in younger adults. Patients with MS (PwMS) are vulnerable to the presence of potential drug–drug interactions (pDDIs) and potential drug–food interactions (pDFIs) as they take numerous medications to treat MS, associated symptoms and comorbidities. Knowledge about pDDIs and pDFIs can increase treatment success and reduce side effects.

Objective:

We aimed at determining the frequency and severity of pDDIs and pDFIs in PwMS, with regard to polypharmacy.

Methods:

In the cross-sectional study, we analysed pDDIs and pDFIs of 627 PwMS aged ⩾18 years. Data collection was performed through patient record reviews, clinical examinations and structured patient interviews. pDDIs and pDFIs were identified using two DDI databases: Drugs.com Interactions Checker and Stockley’s Interactions Checker.

Results:

We identified 2587 pDDIs (counted with repetitions). Of 627 PwMS, 408 (65.1%) had ⩾ 1 pDDI. Polypharmacy (concomitant use of ⩾ 5 drugs) was found for 334 patients (53.3%). Patients with polypharmacy (Pw/P) were found to have a 15-fold higher likelihood of having ⩾ 1 severe pDDI compared with patients without polypharmacy (Pw/oP) (OR: 14.920, p < 0.001). The most frequently recorded severe pDDI was between citalopram and fingolimod. Regarding pDFIs, ibuprofen and alcohol was the most frequent severe pDFI.

Conclusion:

Pw/P were particularly at risk of severe pDDIs. Age and educational level were found to be factors associated with the occurrence of pDDIs, independent of the number of medications taken. Screening for pDDIs/pDFIs should be routinely done by the clinical physician to increase drug safety and reduce side effects.

Risk Factors for the Occurrence of Potential Drug-Drug Interactions in Surgical Patients

Background: Drug-drug interactions are defined as modifications of the drug action that result from the simultaneous administration of another individual drug or several drugs. Nowadays, potential drug-drug interactions (DDIs) are most frequently detected and analyzed using personal digital assistant software programs (online interaction checker tools).

Objective: To determine the risk factors for the emergence of all drug-drug interactions in surgical patients with particular emphasis on clinically significant interactions.

Patients and methods: This was a retrospective cohort analysis of patients treated at the Surgical Clinic of the Clinical Center Kragujevac. Three interaction checkers were used to reveal drug-drug interactions: Medscape, Epocrates and Micromedex.

Results: The study included total of 200 patients, aged 58.54±17.08 years. Average number of drug-drug interactions per patient was between 10.50±9.10 (Micromedex) and 18.75±17.14 (Epocrates). Number of prescribed drugs, antidepressive therapy, antiarrhythmic therapy, number of pharmacological/therapeutic subgroups (2nd level of ATC classification) prescribed, delirium or dementia, diabetes, heart failure, and number of physicians who prescribed drugs to single patient were identified as risk factors for drug-drug interactions while length of hospitalization in days and age of patient in years emerged as protective factors.

Conclusion: Drug-drug interactions are relatively common in surgical patients and predisposed by factors such as number of prescribed drugs or drug group per patient, number of physicians who prescribed drugs, antidepressive therapy, antiarrhythmic therapy, presence of delirium or dementia, diabetes and heart failure. On the other hand, prolonged hospitalization and higher age are factors that reduce the risk of interactions in surgical patients.

Potential drug-drug interactions in patients with cardiovascular diseases: findings from a prospective observational study

Background

Patients with cardiovascular diseases (CVD) are at high risk of experiencing drug–drug interactions (DDIs). The objective of this study was to evaluate the frequency, level and risk factors associated with potential-DDIs (pDDIs) in hospitalized CVD patients at cardiology departments of two tertiary care hospitals in Quetta, Pakistan.

Methods

In the current prospective observational study, a total of 300 eligible CVD inpatients were evaluated for pDDIs using Lexicomp Interact®. The pDDIs were classified into class A (no known interaction); B (no action needed); C (monitor therapy: it is documented that the benefits of an interaction outweigh the risk, appropriately monitor therapy in order to avoid potential adverse outcomes); D (consider therapy modification: it is documented that proper actions must be taken to reduce the toxicity resulting from an interaction); X (avoid combination: the risk of an interaction outweighs the benefits and are usually contraindicated). Multivariate binary logistic regression analysis was used to find factors associated with the presence of Class-D and/or X pDDIs. A p-value < 0.05 was considered statistically significant.

Results

With a median of 8.50 pDDIs per patient, all patients (100%) had ≥ 1 pDDIs. Out of total 2787 pDDIs observed, 74.06% (n = 2064) were of moderate and (n = 483) 17.33% of major severity. Class C pDDIs were most common (n = 1971, 70.72%) followed by D (n = 582, 20.88%), B (n = 204, 7.32%) and X (n = 30, 1.08%). Suffering from cardiovascular diseases other than myocardial infarction (OR 0.053, p-value < 0.001) and receiving > 12 drugs (OR 4.187, p-value = 0.009) had statistical significant association with the presence of class D and/or X pDDIs.

Conclusion

In the current study, pDDIs were highly prevalent. The inclusion of DDI screening tools, availability of clinical pharmacists and paying special attention to the high-risk patients may reduce the frequency of pDDIs at the study sites.

Inappropriate Medication Use In Older Adults According To Beers Criteria In A Tertiary Referral Hospital, In Bolu, Turkey

Aims — We aimed to study the medications used by older adults for any potentially inappropriate medications. Material and Methods — A hundred and four consecutive subjects over 65 years of age who visited our clinic were enrolled in the study. Possible inappropriate medications were defined according to Beers Criteria. Results — A total of 57 women and 49 men were enrolled in the study. Mean ages of the women and men were 78.6±6.1 years and 77.4±5.4 years, respectively (p=0.30). While 18 subjects (17%) had no increased risk due to inappropriate use of medications, 30 were on inappropriate medications that increased renal failure risk, 5 were on inappropriate medication that amplified neurological side effects, 12 were on inappropriate medications that augmented bleeding risk, 20 were on inappropriate medication that lack safety and efficacy data, and 30 were on inappropriate medication that amplified the risk of falls. The number of increased risks according to Beers Criteria was significantly and positively correlated with number of medications used (r=0.366, p<0.001) and the number of comorbidities (r=0.312, p=0.001). Conclusion — The number of increased risks due to inappropriate use of medicines in older adults is positively correlated with the number of medicines used and the number of accompanied diseases. Therefore we suggest that the medicines used by older people should be reviewed in all settings, and unnecessary drugs should be avoided to be prescribed.

Assessment of Potential Drug–Drug Interactions and Their Predictors in Chronic Outpatient Department of Dessie Referral Hospital, Dessie, Northeast Ethiopia

Objective

To assess the prevalence and predictors of Potential drug–drug interactions (DDIs) at the chronic outpatient department of Dessie Referral Hospital, Dessie, Northeast Ethiopia.

Patients and Methods

A cross-sectional study was carried out on the medical records of patients treated in the chronic ambulatory department of Dessie Referral Hospital (DRH), from March 1/2019 to May 30/2019. Ethical clearance was granted from the department of pharmacy, college of medicine, and health sciences, Wollo University. Lexi-comp computer program database was used to detect pDDIs. SPSS version 22 was used to produce a descriptive analysis of the background data and logistic regression to identify predictors of pDDIs.

Results

In this study, the medical record of 300 patients has been reviewed and 489 pDDIs have been identified. The prevalence of pDDIs per patient was 1.63. Of all the identified pDDIs, the moderate severity interactions were the majority, 88.55% (n=433) followed by 8.38% (n=41) of minor, 2.66% (n=13) of major, and 0.41% (n=2) of contraindicated drug interactions. Taking three or more drugs at a time has been found as a statistically significant predictor of the occurrence of pDDIs.

Conclusion

A high rate of moderate severity pDDIs have been recorded. A system of checks and balances should be developed and executed for all those who are involved in prescribing, dispensing, and administration of medications for effective identification and prevention of pDDIs.

Risk Factors Associated With Medication Errors Among Patients Suffering From Chronic Disorders

Introduction: Medication error is unintentional and can be reduced by reducing the risk factors. Patients suffering from chronic diseases are at an increased risk of medication errors.

Objective: This work aims to assess the risk factors associated with medication errors among patients suffering from chronic disorders in hospitals of South Punjab, Pakistan.

Methodology: Multiple logistic regression analysis was used to assess the impact of different risk factors on the prevalence of medication errors in patients suffering from chronic diseases.

Results: A greater risk for the occurrence of medication errors was associated with age ≥60 years (odds ratio, OR = 1.9; 95% CI = 1.3–3.1; p = 0.001), overburdened healthcare system (OR = 2.2; 95% CI = 1.64–3.56; p < 0.000), number of prescribed drugs ≥5 (OR = 1.74; 95% CI = 1.02–2.64; p < 0.000), comorbidities (OR = 2.6; 95% CI = 1.72–3.6; p = 0.003), Charlson comorbidity index (OR = 1.31; 95% CI = 0.49–1.84; p = 0.004), and multiple prescribers to one patient (OR = 1.12; 95% CI = 0.64–1.76; p = 0.001).

Conclusion: Older age, overburdened healthcare system, number of prescribed drugs, comorbidities, Charlson comorbidity index, and multiple prescribers to one patient are significant risk factors for the occurrence of medication errors.

Simultaneous determination of canrenone, digoxin and tolvaptan by UHPLC-MS/MS: application in heart failure patients

Aim: Heart failure patients are frequently given comedication of digoxin and diuretics like spironolactone and tolvaptan. A UHPLC-MS/MS assay for determining canrenone (main active metabolite of spironolactone), digoxin and tolvaptan simultaneously should be developed so as to support related drug-drug interaction studies. Results: A UHPLC-MS/MS method for simultaneous determination of these three drugs in human plasma was established and fully verified as per CFDA guidelines. Chromatographic separation was achieved using a 4-min isocratic elution. Mass analyses were performed under positive electrospray ionization mode. The calibration curves were established over 1.0-400.0 ng/ml for canrenone and tolvaptan while over 0.1-40.0 ng/ml for digoxin. Conclusion: The developed method was feasible in detecting concentration and related drug-drug interaction studies.

Prevalence and significance of potential drug-drug interactions among cancer patients receiving chemotherapy

Background

Cancer patients often receive multiple drugs to maximize their therapeutic benefit, treat co-morbidities and counter the adverse effects of chemotherapy. Concomitant administration of multiple drugs increases the risk of drug interactions leading to compromised therapeutic efficacy or safety of therapy. The purpose of this study was to identify the prevalence, levels and predictors of potential drug-drug interactions (pDDIs) among cancer patients.

Methods

Six hundred and 78 patients receiving chemotherapy from two tertiary care hospitals were included in this cross-sectional study. Patient medication profiles were screened for pDDIs using the Micromedex® database. Logistic regression analysis was performed to identify the predictors of pDDIs.

Results

The overall prevalence of pDDIs was 78%, majority of patients had 1–2 pDDIs (39.2%). A total of 1843 pDDIs were detected. Major-pDDIs were most frequent (67.3%) whereas, a significant association of pDDIs was found between > 7 all prescribed drugs (p < 0.001) and ≥ 3 anti-cancer drugs (p < 0.001). Potential adverse outcomes of these interactions include reduced therapeutic effectiveness, QT interval prolongation, tendon rupture, bone marrow suppression and neurotoxicity.

Conclusions

Major finding of this study is the high prevalence of pDDIs signifying the need of strict patient monitoring for pDDIs among cancer patients. Patients at higher risk to pDDIs include those prescribed with > 7 any types of drugs or ≥ 3 anticancer drugs. Moreover, list of most frequently identified major and moderate interactions will aid health care professional in timely identification and prevention of pDDIs.

Influence of combinations of drugs that act on the CYP2D6 metabolic pathway in the treatment of major depressive disorder: A population-based study

Objective

To describe the frequency of drug combinations (substrate-substrate or substrate-inhibitor) with the potential to interfere with the CYP2D6 metabolic pathway in patients receiving antidepressant medication for major depressive disorder.

Methods

We carried out an observational study using outpatient medical records. We included adult subjects who initiated antidepressant medication during 2008–2010. Patients were assigned to three study groups: no combination, substrate-substrate, and substrate-inhibitor. Follow-up period was 12 months. Main measures: demographics, comorbidity and medication persistence. Statistical analysis included a logistic regression model, P < 0.05.

Results

Five thousand six hundred and thirty patients were recruited (61.9 years, 76.9% female), 24.4% (CI: 23.8 – 26.0%) received some kind of drug combination (substrate-substrate: 15.4%, substrate-inhibitor: 9.0%). Variables significantly associated with drugs combinations that may act on the CYP2D6 metabolic pathway were: dementia (OR = 4.2), neuropathy (OR = 4.2) and stroke (OR = 1.9), P < 0.001. Medication persistence at 12 months was longer in patients with no combination (55.3%) than in patients receiving substrate-substrate (50.5%) or substrate-inhibitor (45.0%) combinations, P < 0.001.

Conclusions

Twenty-five percent of major depressive disorder patients received a combination of drugs with the potential to interfere with CYP2D6 metabolic pathway. These combinations increased with comorbidity and resulted in shorter medication persistence of antidepressant treatment.

Potential drug-drug interactions in outpatient department of a tertiary care hospital in Pakistan: a cross-sectional study

BACKGROUND

Potential drug-drug interactions (pDDIs) are one of the preventable drug related problems having the risk of serious adverse events or therapeutic failure. In developing countries like Pakistan, this issue remains poorly addressed. The objective of this study was to explore prevalence of pDDIs in the Outpatient Department (OPD) of a tertiary care hospital in Pakistan. The secondary aim was to describe the levels of reported pDDIs and develop a list of widespread clinically relevant interactions.

METHODS

Prescriptions of 2400 OPD patients were analyzed for pDDIs through Micromedex Drug-Reax®. Prevalence, severity- and documentation-levels and widespread clinically relevant interactions were reported.

RESULTS

Of total 2400 prescriptions, pDDIs were present in 22.3%. Whereas, moderate- and major-pDDIs were found in 377 (15.7%) and 225 (9.4%), respectively. PDDIs were more prevalent in Medicine (9.2%) and Cardiology (2.6%) as compared with other OPD specialties. Total 942 pDDIs were identified, of which, the majority were either moderate- (61.9%) or major-pDDIs (32.1%). Some of the most common interactions were ibuprofen + levofloxacin (n = 50), ciprofloxacin + diclofenac (32), aspirin + atenolol (24), and diclofenac + levofloxacin (19). The potential adverse outcomes of widespread interactions were seizures, bleeding, QT-interval prolongation, arrhythmias, tendon rupture, hypoglycemia/hyperglycemia, serotonin syndrome, drug toxicity, and decreased therapeutic response.

CONCLUSIONS

OPD patients were at risk to pDDIs, particularly to major- and moderate-pDDIs. Screening of prescriptions for pDDIs and monitoring of pharmacotherapy in terms of response and associated adverse drug events will contribute to patient safety.

Prevalence of drug-drug interactions in geriatric patients at an ambulatory care pharmacy in a tertiary care teaching hospital

Objective

A cross-sectional study was performed from February to May 2015, to estimate the prevalence of drug–drug interactions in geriatric patients at the ambulatory care pharmacy at King Abdul-Aziz Medical City in Jeddah, Saudi Arabia.

Results

A total of 310 patients were included, with a mean age (± SD) of 73.78 ± 6.96, and 48.70% were female. The overall prevalence of DDIs of all categories was 90.64%. Category B DDIs was 55.80%, category C DDIs 87.74%, category D DDIs 51.93%, and category X DDIs 16.45%. Atorvastatine plus omeprazole was identified as the most common interacting pair, with a prevalence of 25.26%. Multivariate logistic regression analysis showed that category D or X DDIs are more likely to occur in the female patient (OR = 1.79; 95% CI 1.07, 2.97), the patient taking more than three medications (OR = 22.62; 95% CI 2.93, 174.83), and the patient with more than two conditions (OR = 3.09; 95% CI 1.81, 5.27).

Potential drug-drug interactions in inpatients treated at the Internal Medicine ward of Tikur Anbessa Specialized Hospital

PURPOSE

Although the concomitant use of multiple drugs often increases therapeutic effectiveness, certain combinations result in unwanted drug-drug interactions (DDIs). Most interactions go unnoticed by physicians due to the absence of new clinical signs and symptoms, and because they often produce a worsening of already existing symptoms. Quantification of the occurrence of the potential DDIs is essential to prevent the harmful effects associated with interactions. This study was launched to assess the prevalence of potential DDIs in the Internal Medicine ward of Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia.

PATIENTS AND METHODS

Cross-sectional data were gathered from the medical charts of 252 randomly selected patients who were admitted to the Internal Medicine ward during August 23 to October 23, 2013, and exposed to at least two concomitant drugs. Potential DDIs were identified using Medscape Drug Interaction Checker. The data were analyzed using SPSS software. Logistic regression analysis was used to determine the presence of association between variables and p-value <0.05 was considered statistically significant.

RESULTS

At least one potential DDI was found in 78.2% of the patients. The mean number of potential interactions per patient was 3.7±3.4. Out of the 719 potential interactions identified, 49.8% were pharmacokinetic type, 44.6% were pharmacodynamic and the remaining 5.6% were unknown mechanisms. Major potential DDIs accounted for 13.1% of the whole interactions; 53.5% were moderate interactions; and the remaining 33.4% were minor interactions. Ceftriaxone, cimetidine and heparin were the three most involved drugs in major potential interactions. Prescription of five or more concomitant drugs was associated with high risk of encountering potential DDIs.

CONCLUSION

The findings of this study showed that the prevalence of potential DDIs among inpatients was high. Pharmacists should closely review drugs prescribed for patients and avoid dispensing combinations of drugs that may have serious DDIs.

Risk factors for potential drug-drug interactions in intensive care unit patients

PURPOSE

To determine risk factors for each severity-based category of potential drug-drug interactions (DDIs) encountered at intensive care unit (ICU) patients.

METHODS

This was a retrospective cohort analysis of patients treated at the ICU of the Clinical Center Kragujevac, a public tertiary care hospital in Kragujevac, Serbia. Three interaction checkers were used to reveal drug-drug interactions: Medscape, Epocrates and Micromedex.

RESULTS

The study included 201 patients, 66.19±16.11 years of age. Average number of DDIs per patient ranged from 10.49±8.80 (Micromedex) to 29.43±21.51 (Medscape). Antiarrhythmic or anticonvulsant drug prescription, Charlson Comorbidity Index, male sex, length of hospitalization, number of drugs or therapeutic groups prescribed and surgery increased the risk of DDIs in ICU patients, while presence of delirium or dementia and transfer from emergency department to ICU protected against.

CONCLUSIONS

The rate of the DDIs in ICU patients at a tertiary care hospital is high, and adversely influenced by number of drugs or drug groups prescribed per patient, antiarrhythmic or anticonvulsant drug prescription, comorbidities, length of hospitalization and surgery. On the other hand, presence of cognitive deficit and transfer from emergency department to ICU protect ICU patients from the DDIs.

Clinically relevant potential drug-drug interactions among outpatients: A nationwide database study

BACKGROUND

Adverse drug events due to drug-drug interactions (DDIs) represent a considerable public health burden, also in Slovenia. A better understanding of the most frequently occurring potential DDIs may enable safer pharmacotherapy and minimize drug-related problems.

OBJECTIVES

The aim of this study was to evaluate the prevalence and predictors of potential DDIs among outpatients in Slovenia.

METHODS

An analysis of potential DDIs was performed using health claims data on prescription drugs from a nationwide database. The Lexi-Interact Module was used as the reference source of interactions. The influence of patient-specific predictors on the risk of potential clinically relevant DDIs was evaluated using logistic regression model.

RESULTS

The study population included 1,179,803 outpatients who received 15,811,979 prescriptions. The total number of potential DDI cases identified was 3,974,994, of which 15.6% were potentially clinically relevant. Altogether, 9.3% (N = 191,213) of the total population in Slovenia is exposed to clinically relevant potential DDIs, and the proportion is higher among women and the elderly. After adjustment for cofactors, higher number of medications and older age are associated with higher odds of clinically relevant potential DDIs. The burden of DDIs is highest with drug combinations that increase risk of bleeding, enhance CNS depression or anticholinergic effects or cause cardiovascular complications.

CONCLUSION

The current study revealed that 1 in 10 individuals in the total Slovenian population is exposed to clinically relevant potential DDIs yearly. Taking into account the literature based conservative estimate that approximately 1% of potential DDIs result in negative health outcomes, roughly 1800 individuals in Slovenia experience an adverse health outcome each year as a result of clinically relevant potential interactions alone.

Introducing the Big Knowledge to Use (BK2U) challenge

The purpose of the Big Data to Knowledge initiative is to develop methods for discovering new knowledge from large amounts of data. However, if the resulting knowledge is so large that it resists comprehension, referred to here as Big Knowledge (BK), how can it be used properly and creatively? We call this secondary challenge, Big Knowledge to Use. Without a high-level mental representation of the kinds of knowledge in a BK knowledgebase, effective or innovative use of the knowledge may be limited. We describe summarization and visualization techniques that capture the big picture of a BK knowledgebase, possibly created from Big Data. In this research, we distinguish between assertion BK and rule-based BK (rule BK) and demonstrate the usefulness of summarization and visualization techniques of assertion BK for clinical phenotyping. As an example, we illustrate how a summary of many intracranial bleeding concepts can improve phenotyping, compared to the traditional approach. We also demonstrate the usefulness of summarization and visualization techniques of rule BK for drug-drug interaction discovery.

Assessment of potential drug-drug interactions and its associated factors in the hospitalized cardiac patients

Drug-drug interactions (DDIs) may result in the alteration of therapeutic response. Sometimes they may increase the untoward effects of many drugs. Hospitalized cardiac patients need more attention regarding drug-drug interactions due to complexity of their disease and therapeutic regimen. This research was performed to find out types, prevalence and association between various predictors of potential drug-drug interactions (pDDIs) in the Department of Cardiology and to report common interactions. This study was performed in the hospitalized cardiac patients at Ayub Teaching Hospital, Abbottabad, Pakistan. Patient charts of 2342 patients were assessed for pDDIs using Micromedex® Drug Information. Logistic regression was applied to find predictors of pDDIs. The main outcome measure in the study was the association of the potential drug-drug interactions with various factors such as age, gender, polypharmacy, and hospital stay of the patients. We identified 53 interacting-combinations that were present in total 5109 pDDIs with median number of 02 pDDIs per patient. Overall, 91.6% patients had at least one pDDI; 86.3% were having at least one major pDDI, and 84.5% patients had at least one moderate pDDI. Among 5109 identified pDDIs, most were of moderate (55%) or major severity (45%); established (24.2%), theoretical (18.8%) or probable (57%) type of scientific evidence. Top 10 common pDDIs included 3 major and 7 moderate interactions. Results obtained by multivariate logistic regression revealed a significant association of the occurrence of pDDIs in patient with age of 60 years or more (p < 0.001), hospital stay of 7 days or longer (p < 0.001) and taking 7 or more drugs (p < 0.001). We found a high prevalence for pDDIs in the Department of Cardiology, most of which were of moderate severity. Older patients, patients with longer hospital stay and with elevated number of prescribed drugs were at higher risk of pDDIs.

A limited number of prescribed drugs account for the great majority of drug-drug interactions

PURPOSE

The purpose of this study was to investigate the prevalence of prescribed combinations of interacting drugs in the Swedish population.

METHODS

This study design was retrospective and cross-sectional, based on a national register of dispensed prescription drugs during the period from January 1 to April 30, 2010. Prescription data was linked to the drug-drug interaction database SFINX to yield the prevalence of interacting combinations dispensed in the population. The study focused in particular on C- (clinically relevant interactions that can be handled, e.g. by dose adjustments), and D-interactions (clinically relevant interactions that should be avoided).

RESULTS

Thirty-eight and 3.8 % of the population were dispensed combinations of drugs classified as C- or D- interactions, respectively, i.e. clinically relevant, involving all therapeutic areas. Half of the D-interactions were associated with increased risk of adverse drug reactions whereas the other half were considered interactions with a potential to cause therapeutic failure. We identified a top 15 list of D-interactions that included 80 % of the total number of interacting drug combinations. Regarding individual drugs, a group of only ten drugs was involved in as much as 94 % of all D-interactions.

CONCLUSIONS

This study reveals that the majority of prescribed interacting drug combinations in Sweden involve a limited number of drugs. The findings may increase the awareness among prescribers of these most common drug interactions in clinical practice and highlight an area for pharmacological education. It may also serve as an inventory of potential interactions within different therapeutic areas for further research.

Pharmacoepidemiological profile and polypharmacy indicators in elderly outpatients

This cross-sectional study was carried out with 1000 elderly outpatients assisted by a Basic Health District Unit (UBDS) from the Brazilian Public Health System (SUS) in the municipality of Ribeirão Preto. We analyzed the clinical, socioeconomic and pharmacoepidemiological profile of the elderly patients in order to identify factors associated with polypharmacy amongst this population. We used a truncated negative binomial model to examine the association of polypharmacy with the independent variables of the study. The software SAS was used for the statistical analysis and the significance level adopted was 0.05. The most prevalent drugs were those for the cardiovascular system (83.4%). There was a mean use of seven drugs per patient and 47.9% of the interviewees used >7 drugs. The variables that showed association with polypharmacy (P value < 0.01) were female gender, age >75 years, self-medication, number of health problems, number of medical appointments, presence of adverse drug events, use of over-the-counter drugs, use of psychotropic drugs, lack of physical exercise and use of sweeteners. The exposition to all these factors justified the high prevalence of polypharmacy amongst the interviewees. These results showed the need to adopt clinical intervention and educational and managerial measures to analyze and promote rationality in the use of drugs amongst the elderly users of SUS.

Incidence of potential drug interactions in medication prescriptions for children and adolescents in the University Hospital Olomouc, Czech Republic

Drug interactions are important potential causes of adverse drug reactions. However, studies of their occurrence in children are almost entirely lacking. This study evaluates the incidence of potential drug interactions (PDIs) in medication prescriptions for children. The study was performed at the University Hospital in Olomouc. PDIs in each patient's prescriptions were identified. Multivariate analysis was performed in order to assess the risk factors confounding the potential interactions. Univariate analysis was used to assess which diagnostic groups and medication groups significantly increase or lower the odds of a potential drug-drug interaction. A total of 6,078 patients meeting the inclusion criteria entered the study. They received 19,522 prescriptions. PDIs were identified in 3.83 % of patients (moderate-to-severe cases in 0.47 %). Patient age (p = 0.008), the average number of prescriptions per visit (p < 0.0001), and the number of visits per year (p < 0.0001) were found to increase the risk of drug interaction. The presence of epilepsy, leukemia, or rheumatoid arthritis and related disease diagnoses were discovered to increase the risk of PDIs significantly.

CONCLUSION

The risk of PDIs in children is low, but it increases significantly with age and the number of drugs prescribed, particularly antiepileptics and immunosuppressants. The finding of a potential interaction in 0.47 % of all children in whom any medication was prescribed should not be underestimated since it means a significant risk for one child out of every 200, and it is also substantially higher in the chronically ill. Pediatricians should be aware of relevant interactions and should prevent them by therapeutic drug monitoring or appropriate clinical and laboratory monitoring.

How many potential drug-drug interactions cause adverse drug reactions in hospitalized patients?

BACKGROUND

Potential drug-drug interactions (DDIs) are frequent in drug prescription but clinically significant are the ones which can result in changes of therapeutic effect of one of the two drugs or in adverse drug reactions (ADRs). The aim of this study was to assess the potential DDIs as well as the DDIs which cause adverse drug reactions (ADRs) in an internal medicine department hospitalized patients.

METHODS

The prospective study included all patients admitted between November 2010 and January 2011 in an internal medicine ward. Information on patients' demographics and their medication use history was obtained from each patient by interview. In addition, medical history, medication use during hospitalization, and relevant laboratory and clinical data were obtained from medical records. Potential DDIs were identified using the Thomson Micromedex program. Each patient was monitored during the hospitalization period in order to detect the ADRs resulting from DDI's if present.

RESULTS

Three hundred and five patients were enrolled in this study during 3 months. Of 1279 potential DDIs, Fourteen led to 13 ADRs out of which 8 were serious and caused hospital admission or prolongation of hospitalization. There was a statistically significant association between ADRs related to DDIs and the presence of ATC (Anatomical Therapeutic Chemical) C medication during hospitalization and the length of hospital stay, in the multivariate analysis.

CONCLUSION

Awareness of the most commonly occurring DDIs should be raised by the utilization of drug-drug interaction guides in the Romanian clinical practice which can help prescribers and pharmacists prevent DDI related ADRs.

Prevalence of potential drug interactions in an Iranian general hospital

The hazards of prescribing many drugs, including side-effects, drug-drug interactions and difficulties of compliance have long been recognized as particular problems when prescribing. This study estimates the rate and factors associated with potential drug-drug interactions in prescriptions from wards of An Iranian General Hospital. Data were retrieved from the pharmacy of a general hospital (200 beds) during one year period 2010. Potential drug-drug interaction were identified using a computerized drug-drug interaction database system (Prescription Analyzer 2000, Sara Rayane Co., Iran). Patients of both genders and 15 years-old or more were included in this study. Prescriptions with two or more drugs prescribed were selected during one year period 2010. Gender number of drugs and therapeutic drug classes on prescriptions were explored as associated factors to drug-drug interaction. The overall prevalence of potential drug-drug interaction was 20.3%. The risks of severe potential drug interactions were relatively high and the rate of potential drug-drug interaction was significantly higher in women (60.6%) and the patients aged over 60 years old (57.1%). The frequency of the potentially severe drug-drug interaction was 10.8% with digoxin-furosemide as the most common interacting pair (5.91%). A positive correlation was found between drug-drug interaction, patient's age, number of drugs and drugs acting on cardiovascular system. So cardiology women inpatients, age more then 60 years old, and patients prescribed digoxin and angiotensin-converting enzyme inhibitors should be closely monitored for adverse outcomes from drug-drug interaction.

Clinically important drug-drug interactions in primary care

WHAT IS KNOWN AND OBJECTIVE

Drug-drug interactions (DDIs) cause considerable morbidity and mortality worldwide and may lead to hospital admission. Sophisticated computerized drug information and monitoring systems, more recently established in many of the emerging economies, including Malaysia, are capturing useful information on prescribing. Our aim is to report on an investigation of potentially serious DDIs, using a university primary care-based system capturing prescription records from its primary care services.

METHODS

We retrospectively collected data from two academic years over 20 months from computerized databases at the Universiti Sains Malaysia (USM) from users of the USM primary care services.

RESULTS AND DISCUSSION

Three hundred and eighty-six DDI events were observed in a cohort of 208 exposed patients from a total of 23,733 patients, representing a 2-year period prevalence of 876·4 per 100,000 patients. Of the 208 exposed patients, 138 (66·3%) were exposed to one DDI event, 29 (13·9%) to two DDI events, 15 (7·2%) to three DDI events, 6 (2·9%) to four DDI events and 20 (9·6%) to more than five DDI events. Overall, an increasing mean number of episodes of DDIs was noted among exposed patients within the age category ≥70 years (P=0·01), an increasing trend in the number of medications prescribed (P<0·001) and an increasing trend in the number of long-term therapeutic groups (P<0·001).

WHAT IS NEW AND CONCLUSION

We describe the prevalence of clinically important DDIs in an emerging economy setting and identify the more common potentially serious DDIs. In line with the observations in developed economies, a higher number of episodes of DDIs were seen in patients aged ≥70 years and with more medications prescribed. The easiest method to reduce the frequency of DDIs is to reduce the number of medications prescribed. Therapeutic alternatives should be selected cautiously.

Prevalence of the coprescription of clinically important interacting drug combinations involving oral anticancer agents in Singapore: a retrospective database study

BACKGROUND

There has been a recent increase in the availability and use of oral anticancer agents (OAAs). Drug-drug interactions (DDIs) involving OAAs pose a major concern in oncology practice due to these drugs' narrow therapeutic indices and potential for compromised efficacy and fatal adverse events.

OBJECTIVE

To assess the prevalence of the coprescription of potentially interacting drug combinations involving OAAs in Singapore.

METHODS

A retrospective review of physicians' electronic prescription records between the years 2007 and 2009 was performed in the largest cancer center in Singapore. An overall prevalence rate of potential DDIs and a prevalence rate for each individual DDI pair were calculated. Logistic regression was used to identify risk factors for potential DDIs.

RESULTS

Fifty-eight clinically significant DDIs were selected for evaluation from Drug Interaction Facts and Micromedex DrugDex. A total of 39,772 OAA prescriptions prescribed to 8837 patients were reviewed. Potential DDI coprescription was found in 5.4% of the patients on OAAs and in 4.7% of the OAA prescriptions. The drug pair prescribed to the largest number of patients was prednisolone and aspirin. About half (53.3%) of the observed DDIs were found on the same prescription. On multivariate analysis, older patients, males, and those taking prednisolone had a higher risk for potential DDIs.

CONCLUSION

Although limited by the data available, the analysis of prescription records found that ∼5% of patients taking OAAs in Singapore were exposed to ≥1 potentially interacting drug combination.

Polypharmacy, aging and potential drug-drug interactions in outpatients in Taiwan: a retrospective computerized screening study

BACKGROUND

Polypharmacy is common in outpatients and has been identified as a major risk factor for drug-drug interactions (DDIs), which are an important cause of adverse drug reactions. There has been a rapid increase in the number of elderly patients worldwide. However, there have been few studies quantifying the impact of both patient age and the number of concomitant drugs prescribed on the probability of potential DDIs per person in general outpatients.

OBJECTIVE

To assess the extent to which polypharmacy and aging are associated with potential DDIs in outpatients at a medical centre in Taiwan.

METHODS

The medications of 81,650 outpatients who visited a medical centre in Taiwan between January 2004 and March 2004 were retrospectively screened for potential DDIs using a computerized drug-interaction program. The main inclusion criteria were a minimum of two drug prescriptions and duration of use of 14 or more days. We also analysed the DDI pattern, which included severity, level of documentation and onset of potential DDIs, and assessed the impact of the number of drugs prescribed and of aging on the prevalence of potential DDIs per person.

RESULTS

The prevalence of potential DDIs was 25.6% (20,902 of 81,650). The mean ± SD age of the 20,902 patients with potential DDIs was 57.5 ± 16.5 years, and 47.6% of these patients were male. The mean ± SD number of prescribed drugs in patients with potential DDIs was 5.8 ± 2.4, and 67.7% of these patients were prescribed more than four drugs. The majority (55.7%) of DDIs were of the C2 pattern (severity: moderate; documentation: probable). The prevalence of potential DDIs increased in a linear mode with increasing age (p < 0.001) and with the number of drugs prescribed (p < 0.001); furthermore, in addition to being independently associated with potential DDIs, these two factors interacted to increase the risk further.

CONCLUSIONS

This study showed that approximately one-quarter of 81,650 outpatients who visited a medical centre in Taiwan over a period of 3 months in 2004 had potential DDIs. We observed independent increases in potential DDIs per person in association with aging and increasing number of prescribed drugs. Furthermore, a significant interaction between these two factors was observed: the effect of aging on the prevalence of potential DDIs increased as the number of prescribed drugs increased. Potential DDIs in outpatients can be reduced by minimizing the number of drugs prescribed following careful consideration of both their benefits and risks, particularly in the aging population.

Potential drug-drug interactions associated with prolonged stays in the intensive care unit: a retrospective cohort study

BACKGROUND AND OBJECTIVES

Drug-drug interactions (DDIs) are one cause of adverse drug events and can cause harm to hospitalized patients. Little has been done to study the relationship between potential DDIs and an increased length of stay (LOS) in the intensive care unit (ICU). The aim of this study was to determine the frequency of potential DDIs during ICU stays and to determine whether the frequency of these adverse events was associated with ICU LOS.

METHODS

This retrospective cohort study was conducted from January to December 2007 in the ICU of the General Hospital of Vitória da Conquista, Brazil. The study population comprised all patients aged >18 years admitted to the hospital's ICU. Demographic and prescription data were collected from medical files. All prescriptions administered during the period were examined. Potential DDIs were identified and classified according to the book Drug Interaction Facts. The median LOS was determined by the Kaplan-Meier method and Cox proportional hazards models were fitted to analyse the relationship between potential DDIs and the LOS.

RESULTS

The study population comprised 236 adults, 158 (67%) of them men, between the ages of 18 and 96 years, with a mean ± SD age of 50 ± 20 years. The median LOS among patients with at least one DDI was 12 days compared with 5 days among those with no DDIs (p < 0.01). Multiple Cox proportional regression analyses showed that a prolonged ICU stay was positively associated with DDIs (hazard ratio [HR] 0.54; 95% CI 0.37, 0.80; p < 0.01), where an HR <1 indicates a variable that increases the risk of prolonged stay (i.e. an adverse outcome). This association was true even after controlling for the cost of hospitalization, the number of procedures and the number of prescribed drugs.

CONCLUSION

In this study, DDIs were found to be associated with a longer ICU stay. Given that LOS is an important indicator of the quality of health care delivered and that DDIs are considered avoidable, specific measures are necessary to increase the recognition of DDIs. E-prescriptions and dispensing programmes associated with a DDI knowledge base can help health professionals identify hazardous drug combinations.

Risk of digoxin intoxication in heart failure patients exposed to digoxin-diuretic interactions: a population-based study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT * Increased frequency of electrolyte abnormalities and cardiac arrhythmias among patients exposed to digoxin-diuretic interactions has been well-documented in numerous descriptive studies. * Nonetheless, a clear causal relationship has not been established in these studies. WHAT THIS STUDY ADDS * The risks of digoxin intoxication associated with use of digoxin in combination with any diuretic use, types of diuretics, combinations of diuretics, and individual diuretics were quantified using a population-based nested case-control study design. * The combined therapy of digoxin with any diuretic is associated with a 3.08-fold increase in the risk of digoxin intoxication. * Regarding diuretic class, the risk carried by loop diuretics is greater than that of thiazides or potassium-sparing diuretics, and the risk varies with different combinations of diuretic classes and individual diuretics. AIMS To quantify the digoxin intoxication risk associated with exposure to digoxin-diuretic interactions, and evaluate whether the risk varies by diuretic type, individually or in combination. METHODS This was a population-based nested case-control study in which data from the National Health Insurance Research Database (NHIRD) in Taiwan were analysed. RESULTS The study cohort comprised 154 058 heart failure (HF) patients taking digoxin between 2001 and 2004, in whom digoxin intoxication requiring a hospitalization (ICD-9 code 972.1) occurred in 595 cases. A total of 28 243 matched controls were also selected for analysis. Cases were 3.08 times (adjusted OR 3.08, 95% CI 2.50, 3.79) more likely to have been prescribed diuretic medication in the previous month than controls. Regarding the class of diuretics, loop diuretics carried the greatest risk (adjusted OR 2.97, 95% CI 2.35, 3.75), followed by thiazides (OR 2.36, 95% CI 1.70, 3.29) and potassium-sparing diuretics (OR 1.72, 95% CI 0.83, 3.56). The risk was also observed to vary with different combinations of diuretics, and the loops/thiazides/potassium-sparing diuretics combination carried the greatest risk (adjusted OR 6.85, 95% CI 4.93, 9.53). Among the individual diuretics examined, hydrochlorothiazide carried the greatest risk (adjusted OR 4.63, 95% CI 2.50, 8.57). CONCLUSIONS This study provided empirical evidence that digoxin-diuretic interactions increased the risk of hospitalization for digoxin intoxication in HF patients. The risk was particularly high for concomitant use of digoxin with a combination of loop diuretics, thiazide and potassium-sparing diuretics. The combined use of digoxin and diuretics should be avoided if possible.

Prevention of adverse drug reactions in intensive care patients by personal intervention based on an electronic clinical decision support system

OBJECTIVE

We investigated the effect of written drug information for senior clinicians on the incidence of drug-drug interactions (DDIs) and DDI-related adverse events in intensive care patients.

DESIGN AND METHODS

A prospective controlled intervention cohort study was conducted in a medical intensive and intermediate care unit in a university hospital. From 1,062 consecutive intensive care patients, those 265 (control: 136, intervention: 129) with > or =8 concurrently prescribed drugs were included in the study (to include high-risk patients with polypharmacy). The DDI information for senior clinicians during an intervention period of 3 months was based on a computerised clinical decision support system (CDSS) containing information on risk and management of 9,453 drug combinations.

RESULTS

The number of patients with at least one DDI at the end of the respective study phase decreased by 18% (relative risk reduction) from 90 (66%) patients in controls to 70 (54%) in the intervention group (p = 0.02). The relative risk of a patient suffering from at least one DDI-related adverse event decreased by 43% from 60 (44%) patients in controls to 32 (25%) in the intervention group (p < 0.01). Among these events, the incidence of QT(C) prolongation was reduced by 64% from 15 (11%) patients in the control group to 5 (4%) in the intervention group (p = 0.04), and the incidence of hypokalemia by 80% from 14 (10%) to 2 (2%, p < 0.01).

CONCLUSION

Written drug information based on a CDSS considerably decreased DDIs and DDI-related adverse events in routine practice.

Potential drug-drug interactions in prescriptions dispensed in community pharmacies in Greece

OBJECTIVES

To evaluate the nature, type and prevalence of potential drug-drug interactions (DDIs) in prescriptions dispensed in community pharmacies in Thessaloniki, Greece. Secondary objectives included the classification of DDIs as per pharmacotherapeutic class of the medications and the investigation of the relationship between medical specialties and the frequency of potential DDIs, as well as the relationship between DDIs and prescription size. Setting DDIs are a common cause of adverse drug reactions (ADRs) among patients using multiple drug therapy. In Greece a reliable computerized surveillance system for monitoring potential DDIs is not yet fully established. As a result, the prevalence of such DDIs in prescriptions dispensed by community pharmacies in Greece is unknown.

METHODS

We conducted a prospective, descriptive study. Over a 3-month period (November 2007-January 2008), a total of 1,553 handwritten prescriptions were collected from three community pharmacies in Thessaloniki, Greece. The prescriptions were processed using the Drug Interactions Checker within the www.drugs.com database. The identified potential DDIs were categorized into two classes, major and moderate, according to their level of clinical significance.

MAIN OUTCOME MEASURES

Overall 213 prescriptions had one or more potential DDIs and a total of 287 major and moderate DDIs were identified. Potential DDIs were identified in 18.5% of all prescriptions. Major DDIs were identified in 1.9% of all prescriptions and represented 10.5% of all DDIs detected, whereas moderate DDIs were identified in 16.6% of all prescriptions and represented 89.5% of all DDIs detected. The rate of DDIs increased with prescription size. The most common drug involved in major DDIs was amiodarone which interacts with potassium-wasting diuretics, digoxin, simvastatin and acenocoumarol.

CONCLUSIONS

Our results indicate that patients in Greece are at risk of ADRs caused by medications due to potential DDIs. An appropriate surveillance system for monitoring such interactions should be implemented and physicians should be more aware of potentially harmful DDIs. Pharmacists can contribute to the detection and prevention of drug-related injuries, especially of clinically meaningful DDIs that pose a potential risk to patient safety.

Effect of the cytochrome P450 2C19 inhibitor omeprazole on the pharmacokinetics and safety profile of bortezomib in patients with advanced solid tumours, non-Hodgkin's lymphoma or multiple myeloma

BACKGROUND AND OBJECTIVE

Bortezomib, an antineoplastic for the treatment of relapsed multiple myeloma and mantle cell lymphoma, undergoes metabolism through oxidative deboronation by cytochrome P450 (CYP) enzymes, primarily CYP3A4 and CYP2C19. Omeprazole, a proton-pump inhibitor, is primarily metabolized by and demonstrates high affinity for CYP2C19. This study investigated whether coadministration of omeprazole affected the pharmacokinetics, pharmacodynamics and safety profile of bortezomib in patients with advanced cancer. The variability of bortezomib pharmacokinetics with CYP enzyme polymorphism was also investigated.

PATIENTS AND METHODS

This open-label, crossover, pharmacokinetic drug-drug interaction study was conducted at seven institutions in the US and Europe between January 2005 and August 2006. Patients who had advanced solid tumours, non-Hodgkin's lymphoma or multiple myeloma, were aged >/=18 years, weighed >/=50 kg and had a life expectancy of >/=3 months were eligible. Patients received bortezomib 1.3 mg/m2 on days 1, 4, 8 and 11 for two 21-day cycles, plus omeprazole 40 mg in the morning of days 6-10 and in the evening of day 8 in either cycle 1 (sequence 1) or cycle 2 (sequence 2). On day 21 of cycle 2, patients benefiting from therapy could continue to receive bortezomib for six additional cycles. Blood samples for pharmacokinetic/pharmacodynamic evaluation were collected prior to and at various timepoints after bortezomib administration on day 8 of cycles 1 and 2. Blood samples for pharmacogenomics were also collected. Pharmacokinetic parameters were calculated by noncompartmental analysis of plasma concentration-time data for bortezomib administration on day 8 of cycles 1 and 2, using WinNonlin version 4.0.1.a software. The pharmacodynamic profile was assessed using a whole-blood 20S proteasome inhibition assay.

RESULTS

Twenty-seven patients (median age 64 years) were enrolled, 12 in sequence 1 and 15 in sequence 2, including eight and nine pharmacokinetic-evaluable patients, respectively. Bortezomib pharmacokinetic parameters were similar when bortezomib was administered alone or with omeprazole (maximum plasma concentration 120 vs 123 ng/mL; area under the plasma concentration-time curve from 0 to 72 hours 129 vs 135 ng . h/mL). The pharmacodynamic parameters were also similar (maximum effect 85.8% vs 93.7%; area under the percent inhibition-time curve over 72 hours 4052 vs 3910 % x h); the differences were not statistically significant. Pharmacogenomic analysis revealed no meaningful relationships between CYP enzyme polymorphisms and pharmacokinetic/pharmacodynamic parameters. Toxicities were generally similar between patients in sequence 1 and sequence 2, and between cycle 1 and cycle 2 in both treatment sequences. Among 26 evaluable patients, 13 (50%) were assessed as benefiting from bortezomib at the end of cycle 2 and continued to receive treatment.

CONCLUSION

No impact on the pharmacokinetics, pharmacodynamics and safety profile of bortezomib was seen with coadministration of omeprazole. Concomitant administration of bortezomib and omeprazole is unlikely to cause clinically significant drug-drug interactions and is unlikely to have an impact on the efficacy or safety of bortezomib.

Sex differences in inappropriate drug use: a register-based study of over 600,000 older people

BACKGROUND

Several studies have observed a higher rate of inappropriate drug use in elderly women than in elderly men, although few have focused explicitly on sex differences. Also, educational level (a measure of socioeconomic status) has been associated with both polypharmacy and inappropriate drug use in the elderly population, which could explain sex differences in inappropriate drug use.

OBJECTIVE

To investigate whether sex is associated with inappropriate drug use in a large general population of older people, after adjustment for age, socioeconomic status (ie, educational level), and comorbidity (ie, number of drugs).

METHODS

We conducted an analysis of data on sex, age, dispensed drugs, and education for people aged 75-89 years who were registered in the Swedish Prescribed Drug Register between July and October 2005 (N = 645,429). The main outcome measures were the filling of prescriptions for anticholinergic drugs or long-acting benzodiazepines, concurrent use of 3 or more psychotropic drugs, and potentially serious drug-drug interactions.

RESULTS

Potentially inappropriate drug use was more common in women (24.6%) than in men (19.3%). More women than men were exposed to all types of inappropriate drug use, except for potentially serious drug-drug interactions. Logistic regression analysis showed that women were more likely to be exposed to potentially inappropriate drug use than were men (OR 1.24; 95% CI 1.23 to 1.26) after adjustment for age, education, and number of drugs (used as a proxy for comorbidity). In particular, female sex was highly associated with inappropriate psychotropic use (eg, long-acting benzodiazepines: adjusted OR [ORadjusted] 1.45; 95% CI 1.42 to 1.49; >3 psychotropic drugs: ORadjusted 1.50; 95% CI 1.47 to 1.53). In contrast, women had a lower probability of potentially serious drug-drug interactions than did men (ORadjusted 0.81; 95% CI 0.80 to 0.83).

CONCLUSIONS

Inappropriate drug use in the elderly should be monitored separately for women and men. Our results suggest that neither socioeconomic status nor comorbidity seem to explain sex differences in inappropriate drug use. Future research in other large study populations is needed for investigation of other explanations behind these sex differences.

[Patient safety based on computer-assisted drug therapy. Electronic check-up of the patient]

Patients in internal medicine frequently experience adverse drug events. Many of those events, however, are avoidable because they are caused by medication errors, which are particularly frequent in drug prescribing. Therefore, practical concepts are needed to make the rapidly growing knowledge on drugs available already during prescription. But also when deviations from standards are intended access to up-to-date information is required. Computer-based systems can offer support for prescribing clinicians to meet these claims and thus improve the quality of pharmacotherapy. To reach this goal, such systems have to be interlinked among each other and with systems of primary, secondary, and tertiary care. They must be based on scientific published evidence and should consider as many factors as possible for individualization of drug therapy. Individualization and focusing on relevant information are prerequisites to prevent inappropriate alerts (over-alerting) and thus to increase acceptance in practical use.

Quality of interaction database management systems

Objective

To identify drug interaction databases (DID) and assess the quality of their structures.

Method

A search was made of the literature for DID and a series of exclusion and structural quality criteria were defined (at least 4 quality criteria: classification according to severity, classification according to level of evidence, bibliographical reference data, description of clinical management, and 11 criteria used for weighting). The level of compliance of every DID with the criteria defined was analysed, together with the level of compliance of each criteria in each DID.

Results

A total of 54 DID were identified, 30 of which complied with exclusion criteria and 15 of which did not meet the minimum criteria. The rest of the criteria were evaluated in 9 DID: Botplus and Medinteract (100%), SEFH Guide, Lexi-interact and Medscape (89%), Hansten (83%), Micromedex and Stockley (78%), Drug Interactions Facts (68%). Ninety-two percent of the DID describe the mechanism of action, 87% classify the information according to the active ingredient, 75% do not state they have any conflict of interest, classify according to level of severity, have electronic format, and are easy to search. A total of 67% are specific DID, 62% are classified according to level of evidence, contain bibliographical references, and describe clinical management.

Conclusions

A third of the DID comply with the minimum criteria. Differences were observed in the level and compliance criteria among Spanish and foreign DID. Some of the main DID used as references in the bibliography have significant structural defects: no web presentation, no multi-check function and others.

Potential drug-drug and drug-disease interactions in prescriptions for ambulatory patients over 50 years of age in family medicine clinics in Mexico City

BACKGROUND

In Mexico, inappropriate prescription of drugs with potential interactions causing serious risks to patient health has been little studied. Work in this area has focused mainly on hospitalized patients, with only specific drug combinations analyzed; moreover, the studies have not produced conclusive results. In the present study, we determined the frequency of potential drug-drug and drug-disease interactions in prescriptions for ambulatory patients over 50 years of age, who used Mexican Institute of Social Security (IMSS) family medicine clinics. In addition, we aimed to identify the associated factors for these interactions.

METHODS

We collected information on general patient characteristics, medical histories, and medication (complete data). The study included 624 ambulatory patients over 50 years of age, with non-malignant pain syndrome, who made ambulatory visits to two IMSS family medicine clinics in Mexico City. The patients received 7-day prescriptions for non-opioid analgesics. The potential interactions were identified by using the Thompson Micromedex program. Data were analyzed using descriptive, bivariate and multiple logistic regression analyses.

RESULTS

The average number of prescribed drugs was 5.9 +/- 2.5. About 80.0% of patients had prescriptions implying one or more potential drug-drug interactions and 3.8% of patients were prescribed drug combinations with interactions that should be avoided. Also, 64.0% of patients had prescriptions implying one or more potential drug disease interactions. The factors significantly associated with having one or more potential interactions included: taking 5 or more medicines (adjusted Odds Ratio (OR): 4.34, 95%CI: 2.76-6.83), patient age 60 years or older (adjusted OR: 1.66, 95% CI: 1.01-2.74) and suffering from cardiovascular diseases (adjusted OR: 7.26, 95% CI: 4.61-11.44).

CONCLUSION

The high frequency of prescription of drugs with potential drug interactions showed in this study suggests that it is common practice in primary care level. To lower the frequency of potential interactions it could be necessary to make a careful selection of therapeutic alternatives, and in cases without other options, patients should be continuously monitored to identify adverse events.

Interaction risk with proton pump inhibitors in general practice: significant disagreement between different drug-related information sources

AIMS

To compare information on drug-drug interactions (DDIs) reported on two standard drug-related information sources (Summary of Product Characteristics and Drugdex system by Micromedex), by assessing the prevalence and predictors of potential DDI with proton pump inhibitors (PPIs) in general practice.

METHODS

From the 'Caserta-1' Local Health-Service database, 156 general practitioners (GPs) were recruited. From more than 180,000 individuals registered on their lists, we selected patients receiving co-prescription of PPI and medications at interaction risk, according to the Italian Summary of Product Characteristics (SPC) of PPI and Drugdex information, during the year 2003. Thereafter, we carried out a regression analysis to identify the predictors of co-prescription at interaction risk with PPI, on the basis of the two information sources. A number of analyses were performed to evaluate agreement on DDI information between the SPC of PPI and Drugdex.

RESULTS

According to SPC and Drugdex, 324 (3.0%) and 958 (9.0%) patients, respectively, received co-prescriptions of PPI and potentially interacting medications during the study period. PPI users' age, type of medication and number of other drug prescriptions per month were independent predictors of receiving co-prescriptions at interaction risk, when considering only Drugdex. With regard to potential DDIs with PPI, a significant disagreement (P < 0.0001) between the two drug-related information sources, was shown through agreement analyses.

CONCLUSIONS

Potential DDIs with PPI are a common health issue in general practice. Estimates of prevalence and predictors of potential DDIs with PPI significantly changes according to the drug information source being used.

Interacciones medicamentosas. Nuevos aspectos

A drug interaction is the quantitative or qualitative modification of the effect of a drug by the simultaneous or successive administration of a different one. The simultaneous administration of several medicines to the same patient can facilitates their appearance. It is difficult to determine their incidence, but it is related to the number of drugs administered simultaneously. Although it is impossible to remember all the clinical relevant interactions, to bare in mind their existence and the possible mechanisms of production can help to identify them and to contribute to their prevention. The most frequent interactions related with clinical problems are the pharmacokinetic ones, mainly those related to the metabolism through the cytochrome P450 system or the presystemic clearance by means of the P-glycoprotein and other drug transporters. Interactions between drugs and grapefruit juice or St John's wort are frequent and it is important to bear in mind in clinical practice.

Clinical drug interactions in outpatients of a university hospital in Thailand

BACKGROUND

A clinical event is likely to occur in patients receiving a pair of drugs, that have the potential to cause an interaction. The occurrence of a clinical drug-drug interaction in outpatients of university hospitals in Thailand is unknown.

PURPOSE

To investigate the occurrence of a clinical event associated with drug-drug interactions in outpatients at a Thai university hospital.

METHODS

A case-control study was established. The case was a sample group, randomly selected from a 1-year sample of outpatient prescriptions containing 'significance-1' potential drug-drug interactions, whereas the control was from the same year but with no potential drug interactions. Medical records of the cases and the controls were reviewed for an adverse event (AE) using a newly developed review form. The odds ratio of occurrence of the AE between the cases and the controls was determined. The AE was assessed for its possibility of being caused from a drug-drug interaction.

RESULTS

The most common specific AE in both the cases and the controls was cough. An unplanned revisit to outpatient department or emergency room was found to be the most common general AE. The odds ratio of the occurrence of an AE in the cases, compared with the controls, was 1.495 (95% CI: 0.917-2.438). The possibility that the AEs resulted from drug interactions in the case group was nine 'probable' patients and 15 'possible' patients, whereas that in the control group was eight 'possible' patients. The most common interacting drug pair was isoniazid-rifampin with an increase in serum hepatic enzymes as the corresponding AE.

CONCLUSIONS

Despite outpatients receiving drug pairs with a high potential for adverse interactions, the rate of occurrence of clinical drug interaction events was low.