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

Positive associations between sex hormones, bone metabolism and cognitive impairment in Chinese oldest-old females

PURPOSE

With a rapid increase in older adults, progressive impairment in cognitive function has become an increasing concern owing to high social and economic burdens. The current study was designed to investigate the associations of sex hormones and bone metabolism with cognitive impairment (CI) in Chinese oldest-old females.

METHODS

There were 396 oldest-old females from the China Hainan Oldest-old Cohort Study (CHOCS). Following standardized procedures, Mini Mental State Examination was effectively completed, and sex hormones and bone metabolism were assessed in these females.

RESULTS

The median age of all females was 101 years (range: from 80 to 116). There were 340 females (86%) with CI. Participants with CI had significantly higher levels of age, progesterone, prolactin and estradiol than those without CI (P < 0.05 for all). Total type I collagen N-terminal elongation peptide [hazard ratio (HR): 1.018, 95%CI: 1.001-1.035] and prolactin (HR: 1.065, 95%CI: 1.005-1.129) levels were positively and significantly associated with CI (P < 0.05 for all).

CONCLUSIONS

Prolactin and total type I collagen N-terminal elongation peptide had positive associations with CI in Chinese oldest-old females. Thus, a balance in sex hormones and bone metabolism may have significant effects on cognitive function during the aging process.

Are pharmacists' knowledge and practice the key to promoting deprescribing of potentially inappropriate medication: a missing link between treatment and outcomes

OBJECTIVES

Deprescribing is a novel strategy whereby medical professionals aim to optimize a patient's prescription program by removing redundant medications. Few studies have looked at the viewpoints of community pharmacists and other healthcare professionals on deprescribing in daily practice. This study's objectives included evaluating community pharmacists' deprescribing knowledge, attitudes and practices, as well as identifying the obstacles to and enablers of deprescribing in daily practice.

METHODS

Five pharmacy students in the last year of their studies polled employees of neighbourhood pharmacies in Abu Dhabi, Dubai, and the Northern Emirates from April 2022 to July 2022. The study's questionnaire was divided into two sections: questions that inquired about the respondents' demographic data and questions that evaluated the respondents' understanding and usage of the deprescribing of potentially harmful medications for patients. The original Bloom's cutoff points were revised and modified to assess the general knowledge and deprescribing practices of United Arab Emirates (UAE) community pharmacists. Multivariate logistic regression identified the variables influencing respondents' deprescribing knowledge and practice.

KEY FINDINGS

The average age of the participants was 30.8 ± 6.4 SD. Of the total, 255 (37.7%) were male and 422 (62.3%) were female. Pharmacists from independent pharmacies constituted 52.9% of the study sample and 47.1% were from Chain pharmacies. Among the participants, 58.8% (n = 398) had 1-5 years of experience and 41.2% (n = 279) had more than 5 years. Nearly three-quarters of the pharmacists (72.1%, 488) graduated from local universities and 27.9% (n = 189) graduated from regional/international universities. The vast majority of the study sample (84.8%, 574) were bachelor's degree holders and 88.3% (n = 598) were pharmacists in charge. Of the total, 69.3% (n = 469) received deprescribing training to treat patients with multimorbid diseases. The knowledge and practice score was 71.3% with a 95% confidence interval [70.2%, 72.4%]. Of the total participants, 113 (16.7%) had poor knowledge and practice about deprescribing, 393 (58.1%) had moderate knowledge and practice and 171 (25.3%) had good knowledge and practice.

CONCLUSION

This study highlights the level of understanding of community pharmacists about deprescribing in the UAE. Although most of the respondents in this study received training on deprescribing, less than half of the community pharmacists were unaware of certain classes (long-acting sulfonylureas, anti-diabetic, antihyperlipidemic and psychotropic drugs) of drugs that are candidates for potential deprescribing. This finding indicates that their knowledge about deprescribing was insufficient. Several barriers community pharmacists face in deprescribing were also identified, with patients' resistance and insufficience being the most prevalent. Therefore, there is a need for improved deprescribing practices to ensure drug safety.

Clinical pattern and drug-related problems among colorectal cancer patients at oncology center in Ethiopia: A hospital-based study

Objective:

Despite the fact that cancer patients are highly susceptible to drug-related problems due to the effects of cytotoxic agents, data are limited due to a lack of studies on those patients. Hence, we aimed to investigate drug-related problems among patients diagnosed with colorectal cancer.

Method:

A registry-based cross-sectional study was conducted on colorectal cancer patients at the Felege Hiwot Comprehensive Specialized Hospital. Socio-demographic and disease-related characteristics, treatment regimens, and drug-related problems were recorded by reviewing medical records. Standard guidelines, protocols, and databases were used to evaluate the occurrence of drug-related problems and the severity of adverse drug reactions. For the analysis, Stata version 16/MP for Windows was used. Logistic regression analysis was employed to investigate the potential-associated factors of drug-related problems. A p-value ⩽ 0.05 was used to declare the statistical significance of each independent variable.

Results:

A total of 150 colorectal cancer patients were included, with a mean age of 51.4 ± 13.8 years. About 30% and 41.3% had stage II and stage III cancers, respectively. About three-quarters (73.8%) of the patients were given 5-fluorouracil-based combination regimens. The prevalence of drug-related problems was found to be 48.7%, with a mean of 2.12 ± 0.93 drug-related problems. In the Felege Hiwot Comprehensive Specialized Hospital, drug–drug interactions and adverse drug reactions were the most prevalent drug-related problems, which accounted for 50 (32.7%) and 49 (32%) cases, respectively. Being elderly (>50 years old) (p = 0.013), having co-morbidity (p = 0.001), and being on five or more medications (p = 0.002) were independent predictors of drug-related problems.

Conclusion:

Fluorouracil-based chemotherapy was the most frequently used treatment regimen. Almost, half of the colorectal cancer patients had one or more drug-related problems. About one-third of patients had adverse drug reactions and drug–drug interactions. Furthermore, age, co-morbidity status, and the number of medications used were significantly associated with drug-related problems. Clinical pharmacy services should be implemented to optimize drug therapy because the majority of colorectal cancer patients have one or more drug-related problems.

Deprescribing practice in a resource-limited setting: Healthcare providers' insights

AIMS

Inappropriate polypharmacy poses risks of adverse drug events, high healthcare costs and mortality. Deprescribing could minimise inappropriate polypharmacy and the consequences thereof. The aim of this study was to evaluate healthcare providers' (HCPs') attitudes toward and experiences with deprescribing practice in Ethiopia.

METHODS

We conducted an institution-based cross-sectional survey among HCPs at the University of Gondar Comprehensive Specialized Hospital, Ethiopia. We used a validated questionnaire developed by Linsky et al. The tool included questions that explore medication characteristics, current patient clinical factors, predictions of future health states, patients' resources to manage their own health and education and experience. One-way ANOVA was used to test the association between sociodemographic variables and their perception of deprescribing decisions.

RESULTS

Of 85 HCPs approached, about 82 HCPs completed the survey, giving a response rate of 96.5%. Most of the participants (n = 73, 89%) have scored less than 1.5 points showing they are reluctant to proactively deprescribe. Physicians seem to be affected by the significant physical health conditions (mean = 1.68) and clinical endpoint like blood pressure (mean = 1.5) to make deprescribing decisions. According to the post hoc analysis of one-way ANOVA, clinical pharmacists seemed to have a better attitude toward deprescribing decisions compared with physicians (P = .025).

CONCLUSION

HCPs' decision to discontinue a medication could be multifactorial. Physicians could be influenced by physical health condition and clinical endpoints for deprescribing decision. Future studies should emphasise on barriers and facilitators to deprescribing practice specific to the context in Ethiopia.

Prevalence of potential drug-drug interactions and associated factors among outpatients and inpatients in Ethiopian hospitals: a systematic review and meta-analysis of observational studies

BACKGROUND

Drug-drug interaction is an emerging threat to public health. Currently, there is an increase in comorbid disease, polypharmacy, and hospitalization in Ethiopia. Thus, the possibility of drug-drug interaction occurrence is high in hospitals. This study aims to summarize the prevalence of potential drug-drug interactions and associated factors in Ethiopian hospitals.

METHODS

A literature search was performed by accessing legitimate databases in PubMed/MEDLINE, Google Scholar, and Research Gate for English-language publications. To fetch further related topics advanced search was also applied in Science Direct and HINARI databases. The search was conducted on August 3 to 25, 2019. All published articles available online until the day of data collection were considered. Outcome measures were analyzed with Open Meta Analyst and CMA version statistical software. Der Simonian and Laird's random effect model, I² statistics, and Logit event rate were also performed.

RESULTS

A total of 14 studies remained eligible for inclusion in systematic review and meta-analysis. From the included studies, around 8717 potential drug-drug interactions were found in 3259 peoples out of 5761 patients. The prevalence of patients with potential drug-drug interactions in Ethiopian hospitals was found to be 72.2% (95% confidence interval: 59.1, 85.3%). Based on severity, the prevalence of major, moderate, and minor potential drug-drug interaction was 25.1, 52.8, 16.9%, respectively, also 1.27% for contraindications. The factors associated with potential drug-drug interactions were related to patient characteristics such as polypharmacy, age, comorbid disease, and hospital stay.

CONCLUSIONS

There is a high prevalence of potential drug-drug interactions in Ethiopian hospitals. Polypharmacy, age, comorbid disease, and hospital stay were the risk factors associated with potential drug-drug interactions.

Prevalence and nature of potential drug-drug interactions among hospitalized HIV patients presenting with suspected meningitis in Uganda

Background

Management of co-infections including cryptococcal meningitis, tuberculosis and other opportunistic infections in persons living with HIV can lead to complex polypharmacotherapy and increased susceptibility to drug-drug interactions (DDIs). Here we characterize the frequency and types of potential DDIs (pDDIs) in hospitalized HIV patients presenting with suspected cryptococcal or tuberculous meningitis.

Methods

In a retrospective review of three cryptococcal meningitis trials between 2010 and 2017 in Kampala, Uganda, medications received over hospitalization were documented and pDDI events were assessed. IBM Micromedex DRUGDEX® online drug reference system was used to identify and describe potential interactions as either contraindicated, major, moderate or minor. For antiretroviral DDIs, the Liverpool Drug Interactions Checker from the University of Liverpool was also used to further describe interactions observed.

Results

In 1074 patients with suspected meningitis, pDDIs were present in 959 (overall prevalence = 89.3%) during the analyzed 30 day window. In total, 278 unique interacting drug pairs were identified resulting in 4582 pDDI events. Of all patients included in this study there was a mean frequency of 4.27 pDDIs per patient. Of the 4582 pDDI events, 11.3% contraindicated, 66.4% major, 17.4% moderate and 5% minor pDDIs were observed. Among all pDDIs identified, the most prevalent drugs implicated were fluconazole (58.4%), co-trimoxazole (25.7%), efavirenz (15.6%) and rifampin (10.2%). Twenty-one percent of the contraindicated pDDIs and 27% of the major ones involved an antiretroviral drug. Increased likelihood of QT interval prolongation was the most frequent potential clinical outcome. Dissonance in drug interaction checkers was noted requiring clinicians to consult more than one database in making clinical decisions about drug combinations.

Conclusions

The overall prevalence of pDDIs in this population is high. An understanding of drug combinations likely to result in undesired clinical outcomes, such as QT interval prolongation, is paramount. This is especially important in resource limited settings where availability of therapeutic drug monitoring and laboratory follow-up are inconsistent. Adequate quantification of the increased likelihood of adverse clinical outcomes from multiple drug-drug interactions of the same kind in a single patient is needed to aid clinical decisions in this setting.

Real-World Analysis of Potential Pharmacokinetic and Pharmacodynamic Drug Interactions with Apixaban in Patients with Non-Valvular Atrial Fibrillation

Purpose

We conducted this study to assess the real-world prevalence, nature, predictors, and clinical necessity of apixaban pharmacokinetic (PK) and pharmacodynamic (PD) drug interactions in patients with non-valvular atrial fibrillation (NVAF) at a tertiary medical institution in Saudi Arabia.

Patients and Methods

An observational retrospective cohort analysis was conducted in adult patients diagnosed with NVAF receiving apixaban for stroke prevention from the period of June 2015 to May 2019.

Results

Of the 1271 patients included in the analysis, 611 (48.1%) patients had potential PD– or PK–drug interactions with apixaban. Of those, 490 (38.6%) patients had potential PD drug–drug interactions (DDIs) and 121 (9.5%) patients had potential PK-DDIs. PD-DDIs with apixaban were mainly with antiplatelet therapy followed by non-steroidal anti-inflammatory drugs and antidepressants. PK-DDIs with apixaban were mainly with combined P-gp/CYP3A4 inhibitors or inducers. History of minor bleeding was positively correlated with PD-DDIs with apixaban, ß coefficient = 0.455 (OR 1.58; 95% CI 1.01–2.45); p<0.05. History of acute coronary syndrome was positively correlated with PD-DDIs with apixaban, ß coefficient = 0.515 (OR 1.60; 95% CI 1.36–1.99); p<0.05. History of heart failure was positively correlated with PK-DDIs with apixaban, ß coefficient = 0.459 (OR 1.58; 95% CI 1.07–2.35); p<0.05. Almost 15% of the included patients had no clinical indication to receive the potential interacting drug with apixaban and about 20% of them were assuming an inappropriate apixaban dose according to the product package insert.

Conclusion

Pharmacodynamics and pharmacokinetics interactions are common in more than half of the patients with NVAF receiving apixaban for stroke prevention in this real-world analysis. Some of these interacting medications are not indicated. Drug–drug interactions should always be considered and monitored with apixaban with a regular assessment of the need for any interacting medication.

Prevalence and determinants of polypharmacy in cardiovascular patients attending outpatient clinic in Ethiopia University Hospital

BACKGROUND

While there are advances in medicine and pharmaceutical care, the burden of medication use has also grown with polypharmacy. In this regard, cardiovascular patients are subjected to polypharmacy for a longer period.

OBJECTIVE

The present study aimed to assess the prevalence and predictors of polypharmacy in cardiovascular outpatients attending the University of Gondar Comprehensive specialized hospital, northwest Ethiopia.

METHODS

A hospital-based cross-sectional study was employed at the University of Gondar Comprehensive Specialized Hospital from March 30 -May 30, 2019. The unique medical registration number of 424 patients was selected by using systematic random sampling to trace the medical chart and followed with an interview to explore the factors related to polypharmacy. All the Statistical analysis was carried out using Statistical Package for Social Sciences (SPSS) version 22. Bivariable and multivariable logistic regressions were used to identify the predictors of polypharmacy in cardiovascular patients.

RESULT

The mean age of the respondents was 56.83 ± 15.27 years. The mean number of medications per patient was 3.3±1.6. The prevalence of polypharmacy was 24.8% in cardiovascular outpatients while cardiovascular specific polypharmacy was 9.2%. Elderly (aged ≥ 65 years and above) patients were nearly two times more likely to had polypharmacy prescriptions with AOR: 1.97; 95% CI: 1.08-3.61; p = 0.027. Patients with abnormal weight (underweight AOR: 4.51; 95% CI: 1.42-14.30; p = 0.010, overweight AOR: 3.78; 95% CI: 1.83-7.83; p<0.001 and obese AOR: 5.1; 95% CI: 2.04-12.75 p<0.001) are more likely to have polypharmacy. Having a family history of CVD increase the likelihood of polypharmacy more than double; AOR: 2.40; 95% CI: 1.17-4.93; p = 0.017. A unit increase in Charlson comorbidity index score resulted in a nearly threefold likelihood of polypharmacy with AOR: 2.83; 95% CI 1.91-3.89; p<0.001.

CONCLUSION

One out of four cardiovascular patients attending the outpatient clinic was on polypharmacy. The elderly age, abnormal body mass index (non-normal weight), family history of cardiovascular diseases and increasing Charlson morbidity index were the predictors of polypharmacy in cardiovascular patients. Clinicians should ensure the relevance of all prescribed medications and pharmaceutical care targeting at the prevention of inappropriate polypharmacy would be pivotal to reduce polypharmacy associated burdens.

The Cancer Drug Fraction of Metabolism Database

This study aims to create a database for quantifying the fraction of metabolism of cytochrome P450 isozymes for cancer drugs approved by the US Food and Drug Administration. A reproducible data collection protocol was developed to extract essential information, including both substrate-depletion and metabolite-formation data from publicly available in vitro selective cytochrome P450 enzyme inhibition studies. We estimated the fraction of metabolism from the curated data. To demonstrate the utility of this database, we conducted an in vitro drug interaction prediction for the 42 cancer drugs. In the drug-drug interaction prediction, we identified 31 drug pairs with at least one cancer drug in each pair that had predicted area under concentration ratios > 2. We further found clinical drug interaction pieces of evidence in the literature to support 20 of these 31 drug-drug interaction pairs.

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

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

Categorization and association analysis of risk factors for adverse drug events

PURPOSE

Adverse drug events (ADE) are among the leading causes of morbidity and hospitalization. This review analyzes risk factors for ADE, particularly their categorizations and association patterns, the prevalence, severity, and preventability of ADE, and method characteristics of reviewed studies.

METHODS

Literature search was conducted via PubMed, Science Direct, CINAHL, and MEDLINE. A review was conducted of research articles that reported original data about specific risk factors for ADE since 2000. Data analyses were performed using Excel and R.

RESULTS

We summarized 211 risk factors for ADE, and grouped them into five main categories: patient-, disease-, medication-, health service-, and genetics-related. Among them, medication- and disease-related risk factors were most frequently studied. We further classified risk factors within each main category into subtypes. Among them, polypharmacy, age, gender, central nervous system agents, comorbidity, service utilization, inappropriate use/change use of drugs, cardiovascular agents, and anti-infectives were most studied subtypes. An association analysis of risk factors uncovered many interesting patterns. The median prevalence, preventability, and severity rate of reported ADE was 19.5% (0.29%~86.2%), 36.2% (2.63%~91%), and 16% (0.01%~47.4%), respectively.

CONCLUSIONS

This review introduced new categories and subtypes of risk factors for ADE. The broad and in-depth coverage of risk factors and their association patterns elucidate the complexity of risk factor analysis. Managing risk factors for ADE is crucial for improving patient safety, particularly for the elderly, comorbid, and polypharmacy patients. Some under-explored risk factors such as genetics, mental health and wellness, education, lifestyle, and physical environment invite future research.

Assessment of Drug-Drug Interaction in Ayder Comprehensive Specialized Hospital, Mekelle, Northern Ethiopia: A Retrospective Study

Introduction

Adverse drug interaction is a major cause of morbidity and mortality. Its occurrence is influenced by a multitude of factors. The influences of drug-drug interactions (DDIs) can be minimized through creation of awareness to health care professionals.

Objective

The objective of this study was to assess DDIs in Ayder Comprehensive Specialized Hospital (ACSH).

Methodology

A retrospective study design was employed on patient prescriptions available in the outpatient department of pharmacy and filled from September 2016 to February 2017 in ACSH.

Result

From the 600 prescription records assessed, the average number of drugs on single prescription was 2.73. Regarding the interaction observed 34 (9.63%) prescriptions with major drug-drug interaction, 210 (59.5%) moderate, 87 (24.65%) minor, and 22 (6.22%) unknown were identified. Age category showed significant association to affect the occurrence of DDIs and polypharmacy had statistically significant association with DDIs in bivariate analysis which was lost in adjusted OR.

Conclusion

From the current study it can be concluded that nearly half of the prescription ordered in ACSH contained DDIs and from the prescription with interacting medications majority of them had moderate DDIs.

Occurrence of drug-drug interactions in Adama Referral Hospital, Adama city, Ethiopia

Objective

Many medications have potential interactions with other drugs or substances when prescribed together. This study was intended to investigate the extent of poly-pharmacy, event of drug–drug interactions and associated ADRs in Adama Referral Hospital, Oromia regional State, Ethiopia to create awareness of potential drug interactions and for development of clinical strategies to prevent the occurrence of DDIs.

Methods

A retrospective study was done at Adama Referral hospital, Adama city, Ethiopia during March–May 2014. Medscape online were used for DDIs and ADRs detection purposes.

Results

The average number of drugs prescribed per person (encounter) in this study was found to be 2.6, showing the presence of poly-pharmacy prescribing practice based on WHO recommendations (1.4–2.4). With 788 medications prescribed, 267 DDIs were found in this study and 62 (20.7%) were categorized as serious DDIs, 95 (31.7%) as significant DDIs, and 110 (36.7%) as minor DDIs. DDIs occurrence was also categorized according to the mechanisms, Pharmacokinetic and pharmacodynamic interactions; the highest frequency of DDIs was observed in 85 (31.8%), attributable to metabolism interaction followed by Antagonistic effect in 51 (21.4%), and Synergistic/Additive effect in 44 (16.5%). It was observed that serious DDIs most often caused possible cardiovascular ADRs.

Conclusions

The results of the study showed the high number of drugs per person compared to the WHO-reported average number of drugs per person and occurrence of DDIs associated with severe cardiovascular risk ADRs in the Adama Referral Hospital. This study recommends that the drug information center facilities and drug prescription validation is done by the pharmacist and the development of pharmacotherapeutic guidelines supporting selection of drugs in Ethiopian hospitals for preventing DDIs and ADRs.

Drug-drug interaction software in clinical practice: a systematic review

PURPOSE

Several electronic databases which report the prevalence of drug-drug interactions (DDIs) are used as a tool for evaluation of potentially harmful DDIs. The aim of our review was to evaluate the usability and appropriateness of commercially available electronic databases which assess the prevalence of potential DDIs.

METHODS

The systematic electronic literature search was conducted with the following search terms: "database" AND "software," and "drug-drug interactions" AND "database," and the inclusion and exclusion criteria were applied in order to identify the publications of interest.

RESULTS

A total of 3766 papers were identified by systematic search. After applying inclusion and exclusion criteria, 38 publications were included in the analysis. The most commonly used software in the included studies was Micromedex® Drug-Reax, for which some authors argue to be the most reliable due to highest sensitivity. It gives information about clinical consequences of DDIs, classifies underlying mechanism and onset of the adverse outcome (either rapid, or delayed) as well as severity (such as minor, moderate, or major), and provides the level of evidence which supports this information. This data is also provided by Drug Interaction Facts®, Lexi-Interact®, and Pharmavista®. A small number of studies which compared assessment of DDIs with electronic database and the clinician's assessment showed large discrepancy in number and relevance of detected DDIs. The overlap was in some cases as low as 11 %.

CONCLUSION

The deficiency of clinical relevance of detected DDIs should be addressed in the upcoming research as it would provide more relevant information to the prescribers' in clinical practice.

Drug-drug interactions and risk of bleeding among inpatients on warfarin therapy: a prospective observational study

Background

Warfarin is known for its interaction with many drugs, resulting in undesired treatment outcomes such as bleeding. The study aimed to assess the prevalence of drug-drug interactions and determinants of bleeding among inpatients on warfarin therapy.

Methods

A cohort of inpatients on warfarin treatment was prospectively followed from date of admission until discharge. The study was carried out from January to October 2013 in Ayder Referral Hospital, Northern Ethiopia. Patients on warfarin therapy during the study period and willing to participate were included as study subjects. Each concurrent medication was collected and checked for drug-drug interactions using Micromedex® online drug reference. Data were analyzed using statistical software, SPSS for windows version 16. The relationship between bleeding complications and independent variables (age, sex, residence, type and number of co-medications, dose and duration of warfarin treatment, INR value) was assessed using binary logistic regression analysis (Odds ratio, 95% confidence interval).

Results

Of the total 133 patients enrolled in the study, 78 (58.9%) were females. The mean age of the study participants was 40.81 ± 17.6 years. The prevalence of drug-drug interactions was 99.2%. Among these, 65 (49.2%) patients had at least one major while the others had moderate level of drug-drug interaction. Twenty two (16.5%) patients have developed bleeding complications. Increase in international normalized ratio value was found to be strongly associated with risk of bleeding (P value = 0.00; OR = 0.03 (0.00-0.46)).

Conclusion

Drug-drug interactions with warfarin were prevalent in the study hospital. Bleeding complications due to warfarin were also high. Thus, clinicians should be aware of potential interactions and monitor patients’ international normalized ratio closely.