A pilot study on the impact of known drug-drug interactions in cancer patients

CA: A Cancer Journal for Clinicians publishes information about the prevention, early detection, and treatment of cancer, as well as nutrition, palliative care, survivorship, and additional topics of interest related to cancer care.

The primary aim of this study is to identify and analyze the importance of adverse drug reaction due to drug-drug interaction as a contributing factor towards drug safety. Patients more than 18 years of age admitted in multidisciplinary intensive care unit of a tertiary care hospital were included in this study. Patients who stayed less than 48 h and patients in whom all treatment modalities have been withdrawn and were on comfort measures only (no drugs were prescribed), were excluded. All the drugs that were given during intensive care unit stay were checked for presence of potential interactions which led to adverse drug reaction. Drug-drug interactions that were detected clinically or through investigations were recorded and also any therapeutic actions taken for drug-drug interactions were noted. From June 2006 to April 2007, 400 patients-prescriptions were analyzed. Adverse drug reactions due to drug-drug interactions were identified in 64% patients. Among those patients 38.67% had a single drug-drug interaction. Potential drug-drug interactions were 602. Clinically significant drug-drug interactions among the potential were 208 (34.55%). Clinically relevant drug-drug interactions were 103 (49.52% of 208 episodes). The adverse drug reactions due to drug-drug interactions in our sample were managed either by substituting another drug (50.48% of 103 episodes) or by adjusting the dose (1% of 103 episodes) or by omitting the drug (48.54% of 103 episodes). Among the 208 observed drug-drug interactions induced adverse drug reactions 21.63% was severe drug-drug interactions induced adverse drug reactions, 23.08% was moderate drug-drug interactions induced adverse drug reactions and 55.29% was minor drug-drug interactions induced adverse drug reactions. The interactions which were life threatening and/ or require medical intervention to minimize or prevent serious adverse effects were considered as severe drug-drug interactions and those interaction which resulted in an exacerbation of the patient's condition and/ or require an alteration in therapy were considered as moderate drug-drug interactions. The interactions which were limited clinical effects and manifestations may include an increase in the frequency or severity of side effects but generally would not require a major alteration in therapy were classified as minor drug-drug interactions. The correlation coefficient was 0.86 between the number of drugs given to the patient & number of average potential adverse drug reactions found among the patients. Increase in number of prescribed drug significantly (one way) increases number of potential adverse drug reaction due to drug-drug interaction (p<0.0001). Critically ill patients are more susceptible to drug-drug interactions due to the administration of multiple drugs and complex drug combinations. Several drug-drug interactions were clinically irrelevant.

e19651 Background: Cancer patients (CP) are frequently exposed to polypharmacy, which may increase their risk for drug interactions. Our study aims were to 1) determine and compare the prevalence and clinical significance of potential drug interactions (PDI) in CP vs. non-cancer patients (NCP) and 2) identify clinical risk factors associated with PDI in CP. Methods: Self-reported prescription medication data from 4,975 patients were extracted from the U.S. population-based National Health and Nutrition Examination Survey and screened for PDI using specialized drug interaction software (iFacts, version 13.10). The clinical significance of each PDI was graded on a 5-point scale (1=most significant and 5=least significant). Clinical significance was judged based on the degree of severity of drug interaction, the rate of onset of side effects (immediate vs. delayed), and the level of scientific evidence for the drug interaction. Summary statistics and logistic regression models were used to assess the impact of cancer history on the risk and significance of PDI. Results: After screening, 302 CP and 907 NCP were eligible for analyses: mean ages were 62 (SD=1.14) and 60 (SD=0.92) years; 44% and 41% were men; 88% and 77% were White, respectively. CP indicated using a mean of 4.5 (SD=0.22) different classes of medications while NCP reported using 3.8 (SD=0.09) different drugs. In terms of PDI, 40% and 43% of CP and NCP, respectively, had interactions. Among them, 12% were rated as level 1 in significance in both patient groups. In multivariate analysis, CP were significantly less likely to be at risk for any type of PDI (OR 0.71, 95% CI 0.52-0.97, p=0.034) when compared to NCP. For level 1 PDI, CP remained less at risk than NCP (OR 0.65, 95% CI 0.46-0.92, p=0.017). Additional factors that were associated with any PDI or level 1 PDI in CP were advanced age and low household income. Medications that were most commonly prescribed among CP with level 1 PDI included atorvastatin (5.2%) and digoxin (4.3%). Conclusions: Although CP appear to be less susceptible to PDI than NCP, the prevalence of medication interactions among CP remains suboptimal. Specific subgroups of CP may be particularly prone to PDI, underscoring the importance of increased vigilance.

Objective: Congestive Heart Failure (CHF) is a notable cardiovascular disease impacting global morbidity and mortality. Geriatric patients with CHF typically require multiple medications that can potentially cause drug-drug interactions and affect patient therapy outcomes. This study aims to determine the potential drug-drug interactions, the relationship between the average number of cardiovascular drugs per day and the potential drug-drug interactions, and the relationship between the severity of drug-drug interactions and the clinical symptoms and signs of the patients. Methods: The research method used was analytical observational with retrospective data collection through the medical records of inpatients in 2021. A total of 63 patients were included using the total sampling method. Results: Results revealed that furosemide was the most commonly prescribed cardiovascular medication (15.27%). Among the participants, 93.65% exhibited potential drug-drug interactions (332 occurrences), with the most frequent involving furosemide and bisoprolol (32 cases). Pharmacodynamic interactions were the dominant mechanism (85.24%), with moderate severity (65.06%) being common. A significant relationship existed between the average number of cardiovascular drugs per day and the potential drug-drug interactions (p&lt;0.05). Nonetheless, there was no notable correlation discovered between the severity of the interaction and the presence of symptoms and clinical signs (p&gt;0.05). Conclusion: When considering the high incidence of potential drug-drug interactions, it is expected that clinical pharmacists have the competence to analyze potential drug interactions to prevent harmful effects on patients.

Given the complex metabolic pathway of antiretroviral therapy (ART), polypharmacy may increase the risk of drug-drug interactions (DDIs). Therefore, we investigated the frequency of DDIs during ART exposure to improve medical care for patients with human immunodeficiency virus (HIV). This was a nationwide cross-sectional study using claims data from the National Health Insurance in Taiwan in 2016. Potential or contraindicated DDIs with recommended first-line ART (1L-ART) or protease inhibitors (PIs) were identified from the University of Liverpool drug interaction database. Fisher's exact or chi-square test was used to determine the significance of categorical variables. A total of 25,863 HIV-infected individuals were identified. Regarding 1L-ART users, patients with contraindicated DDIs accounted for 1-4%, whereas those with potential DDIs accounted for 15-50%. The most frequently coprescribed medications related to potential DDIs were diclofenac and polyvalent cation-containing antacids. Among PI users, 8-10% of them had contraindicated DDIs while 44-50% of them had potential DDIs. The medications related to potential DDIs with PIs were zolpidem, betamethasone, polyvalent cation-containing antacids, and loperamide. Our study showed a low prevalence of contraindicated DDIs in the HIV population; however, more attention should be paid to a high proportion of potential DDIs. Strategies to avoid these DDIs should be implemented if possible. Further research that focuses on the long-term clinical impact of potential DDIs is warranted.

Introduction Drug–Drug interactions (DDIs) are one of the considerable consequences of polypharmacy. Due to the influence of polypharmacy and drug interactions on cancer treatment and patients` health outcomes, this study aimed to determine the prevalence of polypharmacy and potential DDIs among adult cancer patients in Kerman province, southeast of Iran. Methods In this cross-sectional study, 315 cancer patients who referred to Kerman city oncology clinics were assessed in 2018. Data were collected through face-to-face interviews and medical charts were reviewed. Polypharmacy was defined as the use of at least five drugs simultaneously. Potential DDIs were checked using the “Drugs.com” online database. A bivariable and a multivariable logistic regression were used to determine the associated factors of outcome variables, polypharmacy status, and potential DDI in SPSS software version 23. Results Of 315 cancer patients, 191 patients (60.6%; 95% CI: 54.9, 66) used at least five drugs during chemotherapy courses. The prevalence of potential DDIs was 59.6% (n = 140, 95% confidence interval [CI]: 53.6–66.0. Experience co-morbid diseases (OR: 6.60; 95% CI: 3.82, 11.42; p value ≤ .0001), and positive metastatic status (OR: 2.80; 95% CI: 1.62, 4.82; p value ≤ .0001) could predict the polypharmacy during chemotherapy courses. Patients who suffered gastrointestinal cancers (OR: 5.55; 95% CI: 2.26, 13.62; p value ≤ .0001) and the number of prescribed or Over The Counter (OTC) drugs (OR: 1.29; 95% CI: 1.12, 1.48; p value < .0001) predicted the occurrence of potential DDIs among cancer patients. Conclusions Regarding the high prevalence of polypharmacy and potential drug interactions among Iranian cancer patients during chemotherapy courses, it is advisable for physicians, nurses, and pharmacists to be vigilant to improve prescribing patterns. In addition, with intensive monitoring, alternative treatment strategies can be replaced.

Drug-drug interaction (DDI) screening programmes aim to increase the safety of medication by issuing alerts based on the severity of DDIs, since an increased risk of adverse drug events has been reported for some DDIs (clinically relevant alerts). However, not all DDI alerts may be clinically relevant, depending on the clinical decision support system (CDSS) interaction tool used and the target population. There are few data about the frequency and relevance of DDIs in the paediatric population. The objective of this study was to evaluate the prevalence and appropriateness of high-risk DDI alerts (drug combinations that are rated as &ldquo;contraindicated&rdquo; or &ldquo;contraindicated by precaution&rdquo; according to the Swiss CDSS interaction tool Pharmavista&reg; (HCI Solutions AG, Bern, Switzerland)) in paediatric inpatients. We carried out a retrospective, single-centre study examining a cohort of paediatric cases hospitalised between January and May 2017 on the surgery/orthopaedic and oncology wards at the University of Basel Children&rsquo;s Hospital (UKBB), Switzerland. Drugs administered to the patients concomitantly were obtained from the medical records. DDI screening was performed using Pharmavista&reg;. All DDIs detected were documented with their severity grading for each hospital day per case. The clinical relevance of DDI alerts for drug combinations rated as contraindicated or contraindicated by precaution was critically evaluated by a literature review. A total of 300 patient cases were assessed for &ldquo;contraindicated&rdquo; or &ldquo;contraindicated by precaution&rdquo; DDI alerts. Of these, none had &ldquo;contraindicated&rdquo; and five had DDI alerts rated as &ldquo;contraindicated by precaution&rdquo; (1.7%, 95% CI 0.6&ndash;4.1%). The corresponding drug combinations were tramadol/fentanyl/morphine-nalbuphine (n = 3), droperidol-ondansetron (n = 1) and methotrexate-metamizole (n = 1), given for a duration of 1&ndash;2 days. Adverse drug events (ADEs) due to these three combinations (QT prolongation with the combination droperidol-ondansetron, reduced effect of opioid agonists with nalbuphine and increased haematotoxicity with methotrexate-metamizole) were not documented in the patients&rsquo; medical records. The low prevalence of contraindicated DDIs suggests that Pharmavista&reg; has a low risk of over-alerting when used in a Swiss paediatric hospital. However, the current literature suggests that the severity rating of established contraindicated DDIs could be partially downgraded, and that patient/population-specific evaluations of DDI alerts are needed.

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. 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. 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. 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.

PMH1 - Assess Potential Drug-Drug Interaction in Adolescent with Major Depression Disorder

To evaluate the type, frequency, severity and predictors of potential Drug-Drug Interactions (DDIs) in a cohort of patients undergoing radiodiagnostic procedures. Eight Radiology wards located in Tuscany (Italy). All participants exposed to at least two medications were included in the analysis. DDIs were grouped according to their severity as 'minor', 'moderate' or 'major'. A logistic model was used to estimate Odds Ratios and 95% Confidence Intervals for all predictors of potential DDI. Type and predictors of potential DDI in a cohort of patients undergoing radiodiagnostic procedures. One-thousand-and-two subjects (57.6% females; mean age: 67.3 +/- 12.2) entered the analysis, and 46.1% of them incurred in a potential DDI (78.9% 'moderate' in severity). The combination of allopurinol and ACE-inhibitors was the most frequent (21/153) among major potential DDIs, while steroids were involved in all cases of potential DDI due to premedication. Co-morbidity, number of co-medications, advanced age and premedication use increased the risk of potential DDI; a protective role was found for positive history of allergy. When the analysis was restricted to subjects with premedication (n = 93), only 12.9% of them reported a potential DDI directly attributable to premedication drugs. Among patients undergoing radiological examination, types and predictors of potential DDIs appeared in agreement with other kind of in-hospital populations. Premedication revealed to be a proxy predictor for potential DDIs. Considering the poor capability of the prescriber in recognizing interactions, their systematic evaluation (using an informatics tool) in patients undergoing radiological examination might be helpful in preventing the occurrence of clinically relevant DDIs.

Drug-drug interactions (DDIs) are of great concern, as they are known to be related to adverse drug reactions and hospitalisations. In addition, many DDIs are regarded as predictable and avoidable; therefore, they may be considered as targets for education and interventions. To analyse the relationship between number of dispensed drugs and the probability of potential DDIs among the elderly by using the new Swedish Prescribed Drug Register. We analysed data on age, sex and dispensed drugs for people aged > or = 75 years who were registered in the Swedish Prescribed Drug Register from October to December 2005, and constructed a list of current prescriptions for every individual on the arbitrarily chosen date of 31 December 2005. Thereafter, we included those who had at least two dispensed drugs to capture the elderly population at risk of being exposed to DDIs (n = 630 743). The main outcome measures were potentially clinically relevant DDIs (type C), which may require dose adjustment, and potentially serious DDIs (type D), which should be avoided. The prevalence of type C potential DDIs was 26% and of type D potential DDIs 5% in the study population. There was a strong association between number of dispensed drugs and the probability of type C potential DDIs and an even stronger association for type D potential DDIs, after adjustment for age and sex. In addition, the probability of type D potential DDIs decreased with increasing age, and women had a lower probability of type D potential DDIs than men. There seems to be a strong relationship between number of dispensed drugs and potential DDIs, especially for potentially serious DDIs, which has implications for the importance of trying to minimise the number of drugs prescribed in the elderly. Our findings that the probability of potentially serious DDIs decreases with increasing age among the elderly and that elderly women have a lower probability of potentially serious DDIs than elderly men need to be verified and investigated by further research.

Cancer patients receive numerous medications, including antineoplastic agents, drugs for supportive care, and medications for comorbid illnesses. Therefore, they are at risk for drug interactions and duplicate prescribing. A questionnaire eliciting information on demographics and medications taken in the previous 4 weeks was given to adult outpatients receiving systemic anticancer therapy for solid tumors. The Drug Interaction Facts software, version 4.0, was used to identify potential drug interactions and to classify them by level of severity (major, moderate, or minor) and the strength of scientific evidence for them (using categories [1-5] of decreasing certainty). Summary statistics and logistic regression were used to analyze the data. All statistical tests were two-sided. The survey was completed by 405 patients. We observed 276 potential drug interactions, and at least one potential interaction was identified in 109 patients (27%; 95% confidence interval [CI] = 23% to 31%). Of the potential interactions, 25 (9%) were classified as major and 211 (77%) as moderate. Nearly half (49%) of potential interactions were supported by level 1 or 2 scientific evidence. Most potential drug interactions (87%) involved non-anticancer agents such as warfarin, antihypertensive drugs, corticosteroids, and anticonvulsants, but some (n = 36, 13%) involved antineoplastic agents. In multivariable analysis, increased risk of receiving drug combinations in which there were potential drug interactions was associated with receipt of increasing numbers of drugs (odds ratio [OR] = 1.4 per additional drug, 95% CI = 1.26 to 1.58, P<.001 from the Wald chi-square test), type of medication (drugs to treat comorbid conditions versus supportive care medications only; OR = 8.6, 95% CI = 2.9 to 25, P<.001), and the presence of brain tumors. Thirty-two (8%) patients were exposed to duplicate medications, most often corticosteroids, proton pump inhibitors, or benzodiazepines. Potential drug interactions were common among cancer patients and most often involved medications to treat comorbid conditions. Duplicate medications were infrequent.

Liver transplantation for hepatitis C virus (HCV) non-viremic recipients with HCV viremic donors.

Background. Polypharmacy and drug interactions are of particular concern in people living with HIV/AIDS, especially those who receive antiretroviral therapy (ARVs). Polypharmacy and drug-drug interactions (DDIs) can impact the efficacy and toxicity of HIV treatment. ARVs used in HIV treatment are often prone to drug interactions if administered with other non-ARV drugs because many of them are metabolized through the cytochrome P450 system. The pharmacological management of HIV patients in the intensive care unit (ICU) is usually complex and typically involves the administration of several classes of drugs. This patient group may be at higher risk for potential DDIs due to polypharmacy in the ICU. The main objective of this study was to assess the iatrogenic effects of polypharmacy in HIV patients treated in the ICU and to describe the DDI profile between ARVs and other non-ARV medications prescribed in the ICU. Methods and materials. Between 2018 and 2020, we conducted a single-center, retrospective study evaluating the medical records of 59 HIV patients admitted to the ICU for more than 24 hours at the Infectious Disease Clinical Hospital No. 2, Moscow, Russia. We evaluated the impact of polypharmacy on renal, hepatic and haemopoietic function. The Liverpool HIV Drug Interaction database was used to identify DDIs in ART-treated HIV patients. Results. All patients received more than 5 different medications matching the definition of polypharmacy. The average number of concurrent medications prescribed was 156.713 (maximum 40, minimum 6). All drug interactions recorded were between ARVs and antibiotics: 30 cases of potential interactions in 65.5% patients who received ARV. Of such patients, 94% were exposed to at least two potential interactions. Tenofovir (TDF) and the antibiotic vancomycin underlaid the most common potential interaction (49.2%), followed by lopinavir ritonavir (LPV/RTV) and ciprofloxacin (30.3%). A significant difference in average creatinine levels was found in patients with TDF/vancomycin potential interactions (p 0.05). Conclusion. This study demonstrated that potential DDIs frequently occur in ICU patients in line with previous investigations. It is necessary to implement collaborations among clinical pharmacologists and infectious disease/HIV specialists, as well as frequent clinical and laboratory monitoring, aimed at developing effective and actionable strategies that could reduce potential DDIs in HIV patients in the ICU.

Drug-drug interactions (DDIs) may cause adverse drug events, potentially leading to hospital admission. Clinical decision support systems (CDSSs) can improve decision-making by clinicians as well as drug safety. However, previous research has suggested that pharmacists are concerned about discrepancies between CDSSs and common clinical practice in terms of severity ratings and recommended actions for DDIs. The primary objective was to characterize the level of agreement in terms of DDI severity ranking and actions recommended between the local CDSS and pharmacists. The secondary objectives were to determine the level of agreement among pharmacists concerning DDI severity, to determine the influence of the CDSS on clinicians' decision-making, and to review the literature supporting the severity rankings of DDIs identified in the study institution's database. This 2-part survey study involved pharmacists and pharmacy residents working at 1 of 4 health organizations within the Lower Mainland Pharmacy Services, British Columbia, who were invited to participate by email. Participants were first asked to rank the severity of 15 drug pairs (representing potential DDIs) on a 5-point Likert scale and to select an action to manage each interaction. Participants were then given the CDSS severity classification for the same 15 pairs and again asked to select an appropriate management action. Of the estimated 500 eligible pharmacists, a total of 73 pharmacists participated, for a response rate of about 15%. For DDIs of moderate severity, most participants chose to monitor. For severe and contraindicated interactions, the severity ranking and action proposed by participants varied, despite the same severity classification by the CDSS. There was poor agreement among respondents about the severity of the various DDIs. Moreover, knowledge of the CDSS severity ranking did not seem to change the actions proposed by most respondents. This study identified a gap between the local CDSS and clinical practice. There were discrepancies in terms of severity rankings and actions proposed to manage DDIs, particularly for severe and contraindicated DDIs. The current CDSS did not appear to have a large impact on clinical decision-making, which suggests that it may not be functioning to its full potential.