Clinically important potential drug-drug interactions in outpatient settings

Painful diabetic peripheral neuropathy of the feet: integrating prescription-strength capsaicin into office procedures

Prescription-strength (8%) capsaicin topical system is a US FDA-approved treatment for painful diabetic peripheral neuropathy of the feet. A 30 min application of the capsaicin 8% topical system can provide sustained (up to 3 months) local pain relief by desensitizing and reducing TRPV1-expressing cutaneous fibers. Capsaicin is not absorbed systemically; despite associated application-site discomfort, capsaicin 8% topical system is well tolerated, with no known drug interactions or contraindications, and could offer clinical advantages over oral options. Capsaicin 8% topical system are not for patient self-administration and require incorporation into office procedures, with the added benefit of treatment compliance. This article reviews existing literature and provides comprehensive, practical information regarding the integration of capsaicin 8% topical systems into office procedures.

Assessment of potential drug–drug interactions among outpatients in a tertiary care hospital: focusing on the role of P-glycoprotein and CYP3a4 (retrospective observational study)

Background

Selecting a medicine has a significant impact on the quality of therapy including efficacy and safety. P-glycoprotein and CYP3A4 share several common substrates known as bi-substrates. Both play major role in the pharmacokinetics and pharmacodynamics when over or under expressed.

Objective

The study aimed to assess the Drug–Drug Interaction (DDI) related to P-glycoprotein (P-gp) and Cytochrome P450-3A4 (CYP3A4), to predict their clinical outcomes and also to discover prospective predictors of pDDIs.

Methods

The subjects in this retrospective study ranged in age from 18 to 95 years with polypharmacy prescriptions. Information was gathered through patient medical records. Based on Micromedex and previous literature studies, medications prescribed to the patients were observed for pDDIs according to risk rating scale for drug interactions.

Results

A total of 504 patients (160 males and 344 females) were included in the study. The mean of pDDI seen in the patients was 1.66 ± 1.48 and total 825 pDDIs were discovered. The factors significantly associated with having ≥1 pDDIs included: taking ≥5 medicines (OR 1.747), increased age (OR 1.026) increased comorbidities (OR 1.73).

Conclusion

In prescriptions, a considerable number of probable DDI were discovered. Therefore, careful selection of drugs and identification of mechanisms for DDI is needed to lower the frequency of pDDI.

National surveys to evaluate prescribing practices: Methodological considerations

With the changing healthcare landscape, evaluating the care provision in ambulatory settings is vital to understand outpatient care. The national surveys such as the National Ambulatory Medical Care Survey (NAMCS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS) are valuable resources to pharmacy researchers because of their availability and generalizability. With the recent focus on real-world data, the national surveys are critical in providing practice and policy evidence by evaluating ambulatory care, especially prescribing practices. The use of these surveys requires an understanding of the survey content, scope, complex sampling scheme, and analytical and research considerations. There are several methodological and practical considerations that make these national surveys useful to both novice and seasoned researchers. Although some generalized approaches are available for analyzing the national surveys, there is limited focus on the NAMCS and the NHAMCS. This paper provides an in-depth understanding of the NAMCS/NHAMCS, including methodological considerations for evaluating prescribing practices in ambulatory settings.

Impact of Clinical Pharmacist's Interventions on Potential Drug-Drug Interactions in the Cardiac Care Units of Two University Hospitals in Shiraz, South of Iran

Objective:

The main objective of this study aimed to assess drug–drug interactions (DDIs) in the cardiac care unit (CCU) and cardiac surgery units and the role of a clinical pharmacist in detecting and preventing the expected DDIs.

Methods:

This cross-sectional study was conducted in the CCU Units of Nemazee and Shahid Faghihi Hospitals, two referral hospitals in Shiraz, South of Iran, from August to February 2016. Patients older than 18 years, who were admitted and had received >24 h of inpatient services in these wards with two or more medication orders, were included in this study. All medication orders were evaluated by a pharmacist and DDIs were examined based on the Lexi-Interact™ software. In cases with serious DDIs (D or X), the physicians and nurses were informed, and intervention was conducted by a clinical pharmacist.

Findings:

A total of 3706 medical orders were evaluated. 6478 DDIs were detected, of which, 446 (6.88%) belonged to Classes D and X, and a total of 43.43% of all hospitalizations had at least one DDI. Factors with the most considerable influence on DDIs included an increased number of prescribed medications and patients underlying disease. The physicians accepted 62% of the interventions. The most frequent drugs responsible for interactions of Classes C, D, and X were aspirin, warfarin, and clopidogrel, respectively.

Conclusion:

This study shows that a significant number of clinical DDIs exist in hospitalized patients, especially among consumers of warfarin and aspirin. The role of a clinical pharmacist in preventing such interactions and safer pharmacotherapy management for hospitalized patients is essential.

Concurrent prescribing: Evaluation of its knowledge among dentists

Introduction

Considering the staggering number of drugs being prescribed to the patients for dental ailments, the ability of the dentists to recognize potential drug-drug interactions (DDIs) is essential to reduce their occurrence. This study aims to assess the dentist's ability to recognize the potentially clinically significant DDIs in clinical practice.

Subjects and Methods

This questionnaire-based study was carried out among the dentists working at private tertiary care teaching dental hospitals in Jaipur city. Eighty-five dentists working as faculty members in various departments and having postgraduate degree in their respective specialty were enrolled after taking their written informed consent. A prevalidated close-ended questionnaire was given to the respondents to check their knowledge about common DDI possible in clinical dentistry practice.

Statistical Analysis Used

Statistical analysis was done using descriptive statistics. Data were collected in a predesigned Microsoft Excel 2010. Continuous variables were presented as mean values ± standard deviation, and categorical variables were presented as percentages.

Results

Among 85 dentists recruited for the study, no one had knowledge about all the common DDIs in dental practice. The participants could correctly identify only 47.86% of drug pairs. Drug information services available on the Internet were the most common source (32%) of knowledge of DDIs among them. Knowledge of the prescribed drug (40%) and complete drug history including over-the-counter and herbal products (35%) were the two important ways identified by them for avoiding unwanted drug interactions in clinics.

Conclusion

The study revealed that the existing knowledge of the dentists was not adequate. Hence the knowledge of the dentists about DDIs pertinent to dentistry should be enriched and should be reinforced by arranging training sessions at constant intervals of time.

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

Background

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

Methods

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

Results

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

Conclusion

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

Influence of Risk of Drug⁻Drug Interactions and Time Availability on Patient Trust, Satisfaction, and Cooperation with Clinical Pharmacists

Patients with multiple diseases requiring several medications often face the risk of drug-drug interactions (DDIs). Such patients need more care and services from clinical pharmacists. Given the importance of this issue in clinical medicine, the present study aims to investigate how DDIs and time availability affect patient trust in clinical pharmacists and how patient trust influences patient satisfaction and cooperation between patients and clinical pharmacists. Sample data of 741 patients in central Taiwan hospitals were analyzed, and the results of structural equation modeling showed that DDIs and time availability positively affect patient trust, which, in turn, positively influenced patient satisfaction and cooperation between patients and clinical pharmacists. Overall, the results indicated that patient satisfaction is an important predictor of cooperation between patients and clinical pharmacists.

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.

Analysis of Drug-Drug Interactions in Swiss Claims Data Using Tizanidine and Ciprofloxacin as a Prototypical Contraindicated Combination

BACKGROUND

Potential drug-drug interactions (pDDIs) are described in various case reports, but few studies have evaluated the impact of specific combinations on a population level.

OBJECTIVE

To analyze the type and frequency of multiple contraindicated (X-pDDIs) and major interactions (D-pDDIs) and to subsequently assess the impact of the particular combination of tizanidine and ciprofloxacin on outpatient physician visits and hospitalizations.

METHODS

Anonymized Swiss claims data from 524 797 patients in 2014-2015 were analyzed. First, frequencies of X- and D-pDDIs were calculated. Next, a retrospective cohort study was conducted among patients prescribed tizanidine and ciprofloxacin (exposed, n = 199) or tizanidine and other antibiotics (unexposed, n = 960). Hospitalizations and outpatient physician visits within 7, 14, and 30 days after initiation of antibiotic therapy were evaluated using multiple binary logistic regression and multiple linear regression.

RESULTS

The relative frequencies of X- and D-pDDIs were 0.4% and 6.65%, respectively. In the cohort study, significant associations between exposure to tizanidine and ciprofloxacin and outpatient physician visits were identified for 14 and 30 days (odds ratio [OR] = 1.61 [95% CI = 1.17-2.24], P = 0.004, and OR = 1.59 [95% CI = 1.1-2.34], P = 0.016). A trend for increased risk of hospitalization was found for all evaluated time periods (OR = 1.68 [95% CI = 0.84-3.17], OR = 1.52 [95% CI = 0.63-3.33], and OR = 2.19 [95% CI = 0.88-5.02]). Conclusion and Relevance: The interaction between tizanidine and ciprofloxacin is not only relevant for individual patients, but also at the population level. Further investigation of the impact of other clinically relevant DDIs is necessary to improve patient safety and reduce avoidable health care utilization.

Detection and analysis of drug-drug interactions among hospitalized cardiac patients in the Mohammed V Military Teaching Hospital in Morocco

INTRODUCTION

Drug-drug interactions (DDIs) are defined as two or more drugs interacting in such a manner that the effectiveness or toxicity of one or more drugs is altered. Patients with cardiovascular disorders are at higher risk for DDIs because of the types and number of drugs they receive. The aim of the present study was to assess the prevalence of DDIs in patients admitted to the cardiology department of a hospital in Morocco.

METHODS

A prospective observational study from June 2016 to September 2016 was carried out in the cardiology department of a hospital in Morocco. Those patients who were taking at least two drugs and had a hospital stay of at least 48 hours were included in the study. The medications of the patients were analysed for possible interactions. All the prescriptions of the study population were screened for drug-drug interactions using a computerized DDI database system (Theriaque®).

RESULTS

During the study period, 138 patients were included; 360 interactions were detected among 94 patients, with an average number of drugs taken of 5.2. The prevalence of DDIs was estimated at 68.11%, the most common of which concerned Kardegic/Plavix (12.22%), Kardegic/Heparin (8.33%), and Lasilix/Spironolactone (5.83%). Among the 726 prescribed drugs, (372 [51.24%]) were drugs of the cardiovascular system, followed by blood and hematopoietic organ drugs (288 [39.67%]) according to the Anatomical Therapeutic Chemical Classification codes. These interactions were categorized on the basis of level of severity: interactions with major severity accounted for 11.11% (40) of the total DDIs while those with moderate and minor severity accounted for 37.22% (134) and 51.66% (186), respectively.

CONCLUSION

This study reports the prevalence of DDIs in patients admitted to the cardiology department of a hospital in Morocco. This study shows that DDIs are frequent among hospitalized cardiac patients and highlights the need to screen prescriptions of cardiovascular patients for possible DDIs, as this helps in their detection and prevention.Pan African Medical Journal - ISSN: 1937- 8688 (www.panafrican-med-journal.com)Published in partnership with the African Field Epidemiology Network (AFENET). (www.afenet.net)Pan African Medical Journal - ISSN: 1937- 8688 (www.panafrican-med-journal.com)Published in partnership with the African Field Epidemiology Network (AFENET). (www.afenet.net).

A Prospective Analysis of Drug Interactions in Patients of Intensive Cardiac Care Unit

INTRODUCTION

Drug-Drug Interaction (DDI) is a serious concern in cardiac patients due to polypharmacy.

AIM

The present study was aimed to identify the potential DDI among hospitalized cardiac patients and evaluate the mechanism and severity of such interactions.

MATERIALS AND METHODS

A prospective observational study was conducted in intensive cardiac care unit of a tertiary care hospital for six months. Patients aged 18 years and above and taking two or more drugs were included in the study. Medscape drug interaction checker was used to identify and analyze the pattern of potential DDI.

RESULTS

Out of 500 patients, most of the patients were male (78.4%) in the age group of 50-60 years (31%). The most common diagnosis was acute coronary syndrome (57.2%). Out of total 2849 DDI, 2194 (77.01%) were pharmacodynamic, 586 (20.57%) were pharmacokinetic in nature while 69 (2.42%) drug pairs interacted by unknown mechanism. Majority of drug interactions were significant {2031 (71.29%)} in nature followed by minor {725(25.45%)} while serious drug interactions were observed in only 93 (3.26%) drug pairs. A positive correlation was observed between patient's age and number of drugs prescribed (r=0.178, p<0.001), number of drugs prescribed and potential Drug-Drug Interaction (pDDI) (r= 0.788, p<0.001) and between patient's age and pDDI (r=0.338, p<0.001).

CONCLUSION

The risk of pDDI was more commonly observed in elderly male patients particularly with antiplatelet drugs like low dose aspirin and clopidogrel.

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 drug-drug interactions in hypertensive patients at a superspeciality hospital

Objective:

The objective of the study was to assess the incidence and pattern of drug-drug interactions (DDIs) in hypertensive patients by using Micromedex and Medscape databases.

Materials and Methods:

A prospective observational study was carried out in a superspeciality hospital setting in South India for period of 9 months. Hypertensive patients who admitted into the hospital with the age more than 18 years, received more than 3 drugs per prescription and length of hospital stay for more than 24 hours were included in the study. An appropriate data was collected and assessed for DDIs with the help of Micromedex and Medscape databases.

Results:

A total of 227 patients were enrolled during the study period. Among the 227 patients, 48 of them developed 53 clinically significant DDIs. Out of 48 patients, most of them were in the age-group of 50–60 years [18 (37.49%)]. The percentage of DDIs were higher in males [30 (62.5%)] compared to females [18 (37.5%)]. The most common drugs responsible for DDIs in the present study were Insulin [18 (33.96%)] followed by Metoprolol [10 (18.86%)], Torsemide [8 (15.09%)], and Hydrochlorothiazide [8 (15.09%)]. The most commonly interacting pairs were Ciprofloxacin-Insulin [6 (11.32%)], followed by Metoprolol-Insulin [4 (7.54%)] and Atenolol-Insulin [4 (7.54%)]. The most common consequences of interacting pairs were reduced serum potassium levels and hyperglycemia.

Conclusion:

The overall incidence rate of DDIs was found to be 21.14% and the increasing number of co-morbidities (P ≤ 0.003) and polypharmacy (P ≤ 0.002) were the risk factor for the development of significant number of DDIs.

Risk of Fracture and the Concomitant Use of Bisphosphonates With Osteoporosis-Inducing Medications

Objective: To review the literature on the concomitant use of bisphosphonates and medications that can influence bone metabolism and potentially attenuate bisphosphonate antifracture efficacy. Data Sources: MEDLINE and CINAHL were searched for articles published in English through December 2014 using the following terms: bisphosphonates, bone density conservation agents, acid-suppressive therapy, levothyroxine, thiazolidinediones (TZDs), selective serotonin reuptake inhibitors (SSRIs), bone fractures. Study Selection and Data Extraction: Studies were included if they reported results of concomitant use of any listed medications with bisphosphonates and risk of fractures and focused on women. Articles that focused generally on the use of one of the listed medications and fractures without explicitly examining the potential antifracture efficacy or attenuation of bisphosphonates were excluded. Data Synthesis: A total of 6 relevant studies were identified. Four epidemiological studies reported a statistically significant dose-dependent increase in the risk of fractures when bisphosphonates and acid-suppressive drugs were used together. One post hoc analysis of clinical trial data suggested no attenuation of the antifracture effects of bisphosphonates when used concomitantly with acid-suppressive therapy. One study involving bisphosphonates and SSRIs noted a statistically significant association between fracture risk and SSRI use. No study examining TZDs or levothyroxine with bisphosphonates was identified. Conclusions: Existing research suggests potential attenuation of bisphosphonate antifracture efficacy among patients taking acid-suppressive medications. Based on their pharmacological actions, TZDs, SSRIs, and levothyroxine have similar implications. The paucity of evidence in the literature associating the attenuation of bisphosphonate antifracture efficacy when combined with other medications suggests that further investigation is needed.

A study on drug-drug interactions through prescription analysis in a South Indian teaching hospital

OBJECTIVE

The objective of this study was to assess the drug-drug interactions (DDIs) through prescription analysis among the inpatients of a South Indian teaching hospital.

METHODS

The study was a prospective observational prescription analysis conducted for a period of 6 months, from October 2010 to March 2011. The prescriptions having two or more drugs and where a DDI was suspected were selected by the physician in charge of the ward. The drugs in the prescription were then entered into the drug interaction checker software. The DDIs were classified based on the mechanism of interactions, severity of interactions, relation to the number of drugs prescribed, and disease conditions were also determined.

RESULTS

A total of 204 prescriptions were analyzed, of which 186 prescriptions had 856 DDIs. Most of the DDIs were pharmacokinetic drug interactions (42%) followed by unknown mechanisms (34%) and pharmacodynamic mechanisms (24%). The study findings showed that the prescriptions for cardiovascular with respiratory disease conditions had the greatest number of drug interactions on average. A severity assessment showed that majority of the DDIs were moderate (70%) followed by minor (28%). The study results showed that as the number of drugs increases in a prescription, the number of DDIs also increases. The interventions determined showed that dosage adjustment (12%) was to be followed in most of the DDIs.

CONCLUSION

This study assists in understanding the factors associated with DDIs that can help in safe and effective use of drugs in the future.

Identifying and Communicating Clinically Meaningful Drug-Drug Interactions

OBJECTIVE

Providing care to patients with comorbid medical problems may result in complicated, multiple drug therapy regimens, increasing the risk of clinically meaningful drug-drug interactions (DDIs). The purpose of this article is to describe the prevalence of DDIs and provide examples on how to identify and intervene on DDIs.

METHODS

We described DDI data from the Utah Drug Regimen Review Center, where adult Medicaid patients were reviewed by pharmacists from 2005 to 2009. Patients were selected by the number of prescriptions filled per month (>7) or having a high RxRisk score.

SUMMARY

A total of 8860 patients were reviewed, and 16.6% had at least 1 clinically meaningful DDI. Patients with DDIs were slightly younger (mean age 45.2 vs 48.2), more likely to be female (75.0% vs 68.9%), and had more prescriptions per month (13.4 vs 12.5) compared to patients without (P < .001). Pharmacodynamic DDIs were more prevalent (80.2%) than pharmacokinetic. Pharmacodynamic DDIs mainly occurred with drugs used to treat psychiatric/seizure/sleep disorders (69.4%) and pain/migraine (56.6%). Pharmacokinetic DDIs mainly occurred with drugs used to treat psychiatric/seizure/sleep disorders (53.2%), cardiovascular diseases (46.3%), and infectious diseases (29.6%).

CONCLUSIONS

Clinically meaningful DDIs are common in patients with complex medication regimens. A systematic approach for identifying DDIs, determining clinical significance, formulating patient-specific recommendations, and communicating recommendations is important in pharmacy practice.

A study of potential adverse drug-drug interactions among prescribed drugs in medicine outpatient department of a tertiary care teaching hospital

Objective:

To evaluate prevalence, types, and severity of potential adverse drug-drug interaction in medicine out-patient department.

Materials and Methods:

A single-point, prospective, and observational study was carried out in medicine OPD. Study began after obtaining approval Institutional Ethics Committee. Data were collected and potential drug-drug interactions (pDDIs) were identified using medscape drug interaction checker and were analyzed.

Result:

A total of 350 prescriptions with mean age 52.45 ± 14.49 years were collected over a period of 5 months. A total of 2066 pDDIs were recorded with mean of 5.90 ± 6.0. The prevalence of pDDI was 83.42%. Aspirin was most frequently prescribed drug in 185 (10.15%) out of total of 1821 drugs It was also the most frequent drug implicated in pDDI i.e. in 48.16%. The most common pDDI identified was metoprolol with aspirin in 126 (6.09%). Mechanism of interactions was pharmacokinetic in 553 (26.76%), pharmacodynamic in 1424 (68.92%) and 89 (4.30%) having an unknown mechanism. Out of all interactions, 76 (3.67%) were serious, 1516 (73.37%) significant, and 474 (22.94%) were minor interaction. Age of the patients (r = 0.327, P = 0.0001) and number of drugs prescribed (r = 0.714, P = 0.0001) are significantly correlated with drug interactions.

Conclusion:

Aspirin being the most common drug interacting. The use of electronic decision support tools, continuing education and vigilance on the part of prescribers toward drug selection may decrease the problem of pDDIs.

A study of potential drug-drug interactions among hospitalized cardiac patients in a teaching hospital in Western Nepal

AIM

Drug-drug interaction (DDI) is of major concern in patients with complex therapeutic regimens. The involvement of cardiovascular medicines in drug interaction is even higher. However, reports of DDI between these groups of drugs are few. The study aims to identify the potential DDI among hospitalized cardiac patients. Furthermore, we assessed the possible risk factors associated with these interactions.

SUBJECTS AND METHODS

The Type of study prospective observational study was conducted from May 2012 to August 2012 among hospitalized cardiac patients. Cardiac patients who were taking at least two drugs and who had a hospital stay of at least 24 h were enrolled. The medications of the patients were analyzed for possible interactions using the standard drug interaction database - Micromedex -2 (Thomson Reuters) × 2.0.

RESULTS

From a total of 150 enrolled patients, at least one interacting drug combination was identified among 32 patients. The incidence of potential DDI was 21.3%. A total of 48 potentially hazardous drug interactions were identified. Atorvastatin/azithromycin (10.4%), enalapril/metformin (10.4%), enalapril/potassium chloride (10.4%), atorvastatin/clarithromycin (8.3%) and furosemide/gentamicin (6.3%) were the most common interacting pairs. Drugs most commonly involved were atorvastatin, enalapril, digoxin, furosemide, clopidogrel and warfarin. Majority of interactions were of moderate severity (62.5%) and pharmacokinetic (58.3%) in nature. Increased number of medicines, prolonged hospital stays and comorbid conditions were the risk factors found associated with the potential DDI.

CONCLUSIONS

This study highlighted the need of intense monitoring of patients who have identified risk factors to help detect and prevent them from serious health hazards associated with drug interactions.

Extent of poly-pharmacy, occurrence and associated factors of drug-drug interaction and potential adverse drug reactions in Gondar Teaching Referral Hospital, North West Ethiopia

The aim of this study was to assess the extent of poly-pharmacy, occurrence, and associated factors for the occurrence of drug-drug interaction (DDI) and potential adverse drug reaction (ADR) in Gondar University Teaching Referral Hospital. Institutional-based retrospective cross-sectional study. This study was conducted on prescriptions of both in and out-patients for a period of 3 months at Gondar University Hospital. Both bivariate analysis and multivariate logistic regression were used to identify risk factors for the occurrence of DDI and possible ADRs. All the statistical calculations were performed using SPSS(®) software. A total of 12,334 prescriptions were dispensed during the study period of which, 2,180 prescriptions were containing two or more drugs per prescription. A total of 21,210 drugs were prescribed and the average number of drugs per prescription was 1.72. Occurrences of DDI of all categories (Major, Moderate, and Minor) were analyzed and DDI were detected in 711 (32.6%) prescriptions. Sex was not found to be a risk factor for the occurrence of DDI and ADR, while age and number of medications per prescription were found to be significant risk factors for the occurrence of DDI and ADR. The mean number of drugs per prescription was 1.72 and hence with regard to the WHO limit of drugs per prescription, Gondar hospital was able to maintain the limit and prescriptions containing multiple drugs supposed to be taken systemically. Numbers of drugs per prescription as well as older age were found to be predisposing factors for the occurrence of DDI and potential ADRs while sex was not a risk factor.

Drug-drug interactions in hospitalized cardiac patients

Drug–drug interactions (DDIs) are defined as two or more drugs interacting in such a manner that the effectiveness or toxicity of one or more drugs is altered. DDI in patients receiving multidrug therapy is a major concern. The aim of the present study was to assess the incidence and risk factors of DDIs in patients admitted in cardiology unit of a teaching hospital. A prospective, observational study was carried out for a period of 3 months (April–July 2009). During the study period, a total of 600 prescriptions were analyzed and it was found that 88 patients had at least one DDI. The percentage of DDIs was higher in females compared to males (56.82% vs. 43.18%). DDIs were observed more in the age group of 60 years and above (57.96). Patients with more than 10 prescribed drugs developed DDIs more frequently [58 (65.91%)]. Heparin [55 (62.25%)] and aspirin [42 (47.72%)] were the most common drugs responsible for DDIs. Bleeding was the commonest clinical consequence [76 (86.63%)] found in this study population. On assessment of severity of DDIs, majority of the cases were classified as moderate in severity (61.36%). Aging, female gender and increase in concurrent medications were found to be associated with increased DDIs. Patients having these risk factors can be actively monitored during their stay in the cardiology department to identify DDIs.

Drug related problems in type 2 diabetes patients with hypertension: a cross-sectional retrospective study

BACKGROUND

Type 2 diabetes (T2DM) patients with hypertension are at increased risk for experiencing drug-related problems (DRPs) since they often receive multiple medications and have multiple comorbidities. To date, there is a lack of studies conducted in T2DM patients with hypertension. This study aims to analyze the DRPs and identify factors affecting the DRPs in this patient population.

METHOD

This retrospective study involved T2DM patients with hypertension and was conducted at a tertiary hospital in Malaysia from January 2009 to December 2011. The assessment of DRPs was based on the Pharmaceutical Network Care Europe (PCNE) tool version 5.01.

RESULTS

Two hundred patients with a total of 387 DRPs were identified. Among these patients, 90.5% had at least one DRP, averaging 1.9 ± 1.2 problems per patient. The most common DRPs encountered were insufficient awareness of health and diseases (26%), drug choice problems (23%), dosing problems (16%) and drug interactions (16%). The most implicated drugs were aspirin, clopidogrel, simvastatin, amlodipine and metformin. The six domains of DRPs found to have statistically significant associations were renal impairment, polypharmacy, cardiovascular disease, elderly status, and duration of hospital stay.

CONCLUSIONS

Early identification of the types and patterns of DRPs and the factors associated to them may enhance the prevention and management of DRPs in T2DM patients with hypertension.

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.

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.

Potentially serious drug-drug interactions among community-dwelling older adult dental patients

OBJECTIVES

Reducing adverse drug events, including those resulting from drug-drug interactions, will be a health safety issue of increasing importance for dental practitioners in the coming decades as greater numbers of older adults seek oral health care. The purpose of this study was to identify prescription drugs with the potential for serious interactions and estimate prevalent use among older adults visiting the dentist.

STUDY DESIGN

The Medicare Current Beneficiary Survey is an ongoing series of nationally representative surveys of Medicare beneficiaries. Potentially serious drug interactions were selected with the use of published work by Partnership to Prevent Drug-Drug Interactions. Drug interactions were identified and prevalence estimates made for community-dwelling older adults visiting the dentist. Analyses were completed to test associations between sociodemographic and health-related variables and the use of prescription drugs with the potential for serious interactions.

RESULTS

Overall, 3.4% of those visiting the dentist were estimated to have been prescribed drugs with the potential for a serious drug interaction. Drugs commonly prescribed in dentistry with the potential for serious interactions include the benzodiazepines, macrolide antibiotics, and nonsteroidal antiinflammatory analgesics.

CONCLUSIONS

Understanding potentially harmful drug combinations, their clinical consequences, and the frequency with which implicated drugs are being prescribed will assist practitioners in clinically managing patients and avoiding inappropriate prescribing.

Potential drug interactions in patients admitted to cardiology wards of a south Indian teaching hospital

BACKGROUND

The potential drug-drug interaction (pDDI) increases as the number of concomitant medications increases. Patients with cardiovascular disorders are at higher risk for drug- drug interactions because of the types and number of drugs they receive. While drug interactions are reported to be common, there is no published report of the prevalence of such interactions among Indian cardiac patients. The aim of the present study was to identify the pattern of pDDI and document any observed interaction. It was also planned to evaluate the demography of patients and correlate it with the drug-drug interactions.

METHOD

A prospective observational study from Oct 2007 to Apr 2008 was carried out in 'cardiology department' of a hospital in South India. Those patients who were taking at least two drugs and had a hospital stay of at least 48 hours were included in the study. The medications of the patients were analyzed for possible interactions. Factors associated with pDDI were studied. The actual interactions that were observed during the hospital stay in the study subjects were documented.

RESULTS

A total of 812 patients were included in the study. 388 pDDIs were identified among 249 patients. The incidence of pDDI was 30.67%. The most common potential interactions were between aspirin & heparin (29.38%), and clopidogrel & heparin (7.21%). Drug classes most commonly involved were antiplatelets, anticoagulants and diuretics. Majority of interactions were of moderate severity, delayed onset, and pharmacodynamic in nature. Total 68 actual interactions were observed in the observed cases.

CONCLUSION

The present study identified pDDIs and also documented interactions in cardiovascular patients. Factors which had correlation with adverse drug interactions were identified. This study highlights the need for screening prescriptions of cardiovascular patients for pDDIs and proactive monitoring of patients who have identified risk factors; this helps in detection and prevention of possible adverse drug interactions.

Risk of potential drug-drug interactions among Brazilian elderly: a population-based, cross-sectional study

BACKGROUND

Drug-drug interactions (DDIs) are one of the main causes of adverse reactions related to medications, being responsible for up to 23% of hospital admissions. However, only a few studies have evaluated this problem in elderly Brazilians.

OBJECTIVES

To determine the prevalence of potential DDIs (PDDIs) in community-dwelling elderly people in Brazil, analyse these interactions with regard to severity and clinical implications, and identify associated factors.

METHODS

A population-based cross-sectional study was carried out involving 2143 elderly (aged >or=60 years) residents of the metropolitan area of Sao Paulo, Brazil. Data were obtained from the SABE (Saúde, Bem estar e Envelhecimento [Health, Well-Being, and Aging]) survey, which is a multicentre study carried out in seven countries of Latin America and the Caribbean, coordinated by the Pan-American Health Organization. PDDIs were analysed using a computerized program and categorized according to level of severity, onset, mechanism and documentation in the literature. The STATA software statistical package was used for data analysis, and logistic regression was conducted to determine whether variables were associated with PDDIs.

RESULTS

Analysis revealed that 568 (26.5%) of the elderly population included in the study were taking medications that could lead to a DDI. Almost two-thirds (64.4%) of the elderly population exposed to PDDIs were women, 50.7% were aged >or=75 years, 71.7% reported having fair or poor health and 65.8% took 2-5 medications. A total of 125 different PDDIs were identified; the treatment combination of an ACE inhibitor with a thiazide or loop diuretic (associated with hypotension) was the most frequent cause of PDDIs (n = 322 patients; 56.7% of individuals with PDDIs). Analysis of the PDDIs revealed that 70.4% were of moderate severity, 64.8% were supported by good quality evidence and 56.8% were considered of delayed onset. The multivariate analysis showed that the risk of a PDDI was significantly increased among elderly individuals using six or more medications (odds ratio [OR] 3.37) and in patients with hypertension (OR 2.56), diabetes mellitus (OR 1.73) or heart problems (OR 3.36).

CONCLUSIONS

Approximately one-quarter of the elderly population living in Sao Paulo could be taking two or more potentially interacting medicines. Polypharmacy predisposes elderly individuals to PDDIs. More than half of these drug combinations (57.6%, n = 72) were part of commonly employed treatment regimens and may be responsible for adverse reactions that compromise the safety of elderly individuals, especially at home. Educational initiatives are needed to avoid unnecessary risks.

Reliability and Validity of 5 Databases for the Identification of Warfarin-Medication Interactions

Databases are used to screen for warfarin-medication interactions. We measured the reliability and validity of 5 databases. Databases were queried for 30 medications identified as having varying degrees of interactions with warfarin in a recent systematic literature review. Reliability was measured by the percentage agreement between the databases for each interaction and validity was measured by agreement between each database and the systematic literature review. All of the databases and the systematic review agreed on 14 medications (47%). There were 5 medications (17%) where all databases reported an interaction, but no interaction was noted by the systematic review. The databases did not agree on the remaining 11 medications (37%). Four of these interactions were of moderate or greater clinical significance. These commonly used databases frequently do not agree on the occurrence of warfarin-medications interactions, and some interactions identified by the best clinical evidence were not identified in several databases.

Drug-drug interactions in general hospital and psychiatric hospital in-patients prescribed psychotropic medications

Abstract Objectives. Drug-drug interactions (DDIs) present a serious, ever increasing clinical problem. Previous studies identified DDIs among psychiatric inpatients prescribed psychotropics, but none have focused on psychotropics prescribed to General Hospital inpatients. This study aimed to identify: putative drug-drug interactions; mechanisms; potential seriousness among patients prescribed psychotropes in both psychiatric and general hospital inpatients settings. We hypothesised that potential interactions per person would be greater in General Hospital inpatients on psychotropics, due to polypharmacy. Method. We surveyed psychotropic prescribing in hospital wards in a public sector mental health organisation and a 500-bed general hospital. Ward pharmacists collected drug prescription data. A computer based protocol evaluated DDIs. Results. A total of 7.4% of General Hospital inpatients and 100% of Psychiatric Unit inpatients surveyed were prescribed psychotropic medication. The General Hospital group had significantly more potential interactions per person (3.0) than Psychiatric inpatients (1.3) (P<0.05). There were significantly more potentially serious interactions in the general hospital group (P<0.025). Conclusions. DDIs affect those prescribed psychotropics in both General and Psychiatric Hospitals. The General Hospital patients had a higher number per person and more serious potential interactions, yet are often poorly served by psychiatric services, suggesting that liaison psychiatrists have a role in physician education and DDI assessment.

Personal digital assistant with a barcode reader--a medical decision support system for nurses in home care

INTRODUCTION

Inappropriate medication among elderly people increases the risk of adverse drug-drug interactions, drug-related falls and hospital admissions. In order to prevent these effects it is necessary to obtain a profile of the patients' medication. A personal digital assistant (PDA) can be used as a medical decision support system (MDSS) to obtain a profile of the patients' medication and to check for inappropriate drugs and drug combinations, and to reduce medication errors.

AIM

The aim of the present study was to evaluate nurses' experiences of using a MDSS in a PDA with a barcode reader, in order to obtain profiles of the patients' medication, regarding drug-drug interactions, therapeutic duplications, and warnings for drugs unsuitable for elderly in home care.

METHODS

The LIFe-reader is a MDSS in a PDA with a barcode reader. By scanning the drug packages in the patients' home, the LIFe-reader obtained profiles of the patients' medication and checked for drug-drug interactions, therapeutic duplications and warnings for drugs unsuitable for elderly people. The LIFe-reader also contained, e.g. drug information and medical reference works. Nurses (n=15) used the LIFe-reader for five weeks during their nursing home care practice assignment. The nurses answered questionnaires about the content and functions of the LIFe-reader before, during and after the nursing home care practice assignment, and were interviewed in focus groups. Descriptive statistics were used and content analysis was applied for qualitative data.

RESULTS

By using the LIFe-reader, the majority of the nurses found it easy to obtain profiles of the patients' medication and check for drug-drug interactions, therapeutic duplications and warnings for drugs unsuitable for elderly people. Most nurses regarded the LIFe-reader to reduce drug-related risks of falling, and some thought it could reduce the drug-related admissions to hospitals. The scanning function was described as easy and time saving, although not always possible to use. The LIFe-reader was regarded as a useful and user-friendly MDSS, but more content and functions were requested.

CONCLUSIONS

We found that the LIFe-reader has the potential to be a useful and user-friendly MDSS for nurses in home care when obtaining profiles of the patients' medication regarding drug-drug interactions, therapeutic duplications and warnings for drugs unsuitable for elderly. A regular scanning of the patients' drugs in their home might support nurses and general practitioners (GPs) in reducing the inappropriate use of drugs. If the LIFe-reader should be used in a larger scale among nurses, more content and functions are necessary.