Drug–drug interactions in oncology: Why are they important and can they be minimized?

Potential drug-drug interactions and associated factors among hospitalized pediatric patients in Adigrat general hospital, Tigrai, north Ethiopia: a retrospective cross-sectional study

BACKGROUND

Drug-drug interactions (DDIs) are associated with increased or decreased adverse effects and decreased or decreased therapeutic effects. Hospitalized pediatric patients are exposed to a number of potential DDIs (pDDIs). There are limited studies on pDDIs among pediatric patients in Ethiopia. This study was aimed to evaluate the pDDIs and associated factors among hospitalized pediatric patients in Adigrat general hospital, Tigrai, northern Ethiopia.

METHODS

A retrospective cross-sectional study was carried out among hospitalized pediatric patients in Adigrat general hospital from 01 July 2020 to 31 August 2020. A simple random sampling technique was used to select medical charts. Micromedex 2.0 database was used to screen pDDIs. Data was analyzed using statistical package for social science version 21 and a P-value of ≤ 0.05 was considered statistically significant.

RESULTS

Of the total 146 patients studied, 100 (68.5%) were exposed for at least one pDDI. A total of 158 pDDIs consisting of 33 distinct interacting drug pairs were identified. About 19.3% of the patients had at least one major pDDI, 6.7% at least one moderate and 68.9% at least one minor pDDIs. On the other hand, 63.3% of the total pDDIs were minor and 25.9% major while 3. 8% were contraindicated pDDIs with 15.2% fair and 81.6% good level of documentation. The overall mean duration of pDDIs exposure was about 4.9 (1-23) days. The frequently occurring potential clinical consequences of pDDIs comprised increased risk of QT-interval prolongation (10.1%), theophylline toxicity (5.1%), antiepileptic toxicity (5.1%) and formation of ceftriaxone calcium precipitates (3.8%). Infant/toddler age group (adjusted odds ratio [AOR] = 31.961, 95% CI: 1.117-914.528), number of diseases (AOR = 0.255, 95% CI: 0.069-0.939) and polypharmacy (AOR = 0.276, 95% CI: 0.091-0.838) were associated with pDDIs exposures.

CONCLUSIONS

A large number of pediatric patients were exposed to a various pDDIs. Age, number of diseases and polypharmacy predicted for the occurrence of pDDIs. Besides, the major severity pDDIs encounted frequently in the current study can potentially lead to a life threatening cardio-vascular toxicicty from QT-interval prolongation. Clinicians should be vigilant to pDDIs to prevent potential clinical consequences of pDDIs. Moreover, computerized drug interaction screening and clincal pharmacy services should be practiced to improve patients' safety.

Adverse reactions of immune checkpoint inhibitors combined with Proton pump inhibitors: a pharmacovigilance analysis of drug-drug interactions

BACKGROUND

Combining immune checkpoint and proton pump inhibitors is widely used in cancer treatment. However, the drug-drug interactions of these substances are currently unknown. This study aimed to explore drug-drug interactions associated with concomitant immune checkpoint and proton pump inhibitors.

METHODS

Data were obtained from the US Food and Drug Administration Adverse Event Reporting System from 2014 to 2023. Disproportionality analysis was used for data mining by calculating the reporting odds ratios (RORs) with 95% confidence intervals (95%Cls). The adjusted RORs (RORadj) were then analysed using logistic regression analysis, considering age, sex, and reporting year. Drug-drug interactions occur when a combination treatment enhances the frequency of an event. Further confirmation of the robustness of the findings was achieved using additive and multiplicative models, which are the two statistical methodologies for signal detection of DDIs using spontaneous reporting system.

RESULTS

The total number of reports on immune checkpoint combined with proton pump inhibitors was 4,276. Median patient age was 66 years (interquartile range [IQR]: 60-74 years). Significant interaction signals were observed for congenital, familial and genetic disorders (RORadj = 2.66, 95%CI, 1.38-5.14, additive models = 0.7322, multiplicative models = 3.5142), hepatobiliary disorders (RORcrude = 6.64, 95%CI, 5.82-7.58, RORadj = 7.10, 95%CI, 6.16-8.18, additive models = 2.0525, multiplicative models = 1.1622), metabolism and nutrition disorders (RORcrude = 3.27, 95%CI, 2.90-3.69, RORadj = 2.66, 95%CI, 2.30-3.08, additive models = 0.6194), and skin and subcutaneous tissue disorders (RORcrude = 1.41, 95%CI, 1.26-1.58, RORadj = 1.53, 95%CI, 1.34-1.75, additive models = 0.6927, multiplicative models = 5.3599). Subset data analysis showed that programmed death-1 combined with proton pump inhibitors was associated with congenital, familial, and genetic disorders; hepatobiliary disorders; and skin and subcutaneous tissue disorders. Programmed death ligand-1 combined with proton pump inhibitors was associated with adverse reactions of metabolism and nutrition disorders. Cytotoxic T-lymphocyte antigen-4 combined with proton pump inhibitors was associated with congenital, familial, and genetic disorders, and skin and subcutaneous tissue disorders.

CONCLUSIONS

Based on real-world data, four Standardized MedDRA Query System Organ Class toxicities were identified as drug-drug interactions associated with combining immune checkpoint and proton pump inhibitors. Clinicians should be cautious when administering these drugs concomitantly. Preclinical trials and robust clinical studies are required to explore the mechanisms and relationships underlying interactions, thus improving understanding of drug-drug interactions associated with this combination therapy.

Assessment of drug-drug interactions among patients with hematologic malignancy: A clinical pharmacist-led study

INTRODUCTION

Patients with hematologic malignancies often receive multiple medications, leading to potential drug-drug interactions (DDIs). Identifying and managing these DDIs is crucial for ensuring patient safety and effective care. This study aimed to identify and describe DDIs and associated factors in hematologic malignancy patients.

METHODS

This prospective interventional study was conducted at a referral center and included hospitalized patients with hematologic malignancies who were receiving at least four concurrent medications. A pharmacist initially compiled a comprehensive list of all medications through patient interviews and medication reviews, and subsequently, identified and categorized potential DDIs using the Lexi-interact® and Micromedex® databases. The clinical pharmacist then evaluated the clinical impact of the identified DDIs in every individual patient and provided appropriate interventions to resolve them.

RESULTS

A total of 200 patients met the inclusion criteria for the study, with 1281 DDIs identified across 337 distinct types. The majority of identified DDIs exhibited major severity (52.1%) and pharmacokinetic mechanisms (50.3%), with an unspecified onset (79.4%) and fair evidence (67%). Of the identified DDIs, 81.1% were considered clinically significant, prompting 1059 pharmacotherapy interventions by the clinical pharmacist. Additionally, a significant relationship was observed between the number of drugs used during hospitalization and the occurrence of DDIs (P < 0.001, r = 0.633).

CONCLUSION

DDIs are highly prevalent among hospitalized patients with hematologic malignancies, with their occurrence increasing alongside the number of medications administrated. The intervention of a clinical pharmacist is crucial to evaluate the clinical impact of these DDIs and implement effective interventions for their management.

Polypharmacy and drug interactions in older patients with cancer receiving chemotherapy: associated factors

BACKGROUND

Polypharmacy in older adults with cancer receiving chemotherapy leads to increased risks of drug interactions, translating in potential hazardous health outcomes. This study aims to assess the prevalence of polypharmacy, drug-drug interactions (DDIs), and severe-drug interactions (SDIs) in older patients with cancer. Antineoplastic agents (ANAs) involvement and possible risk contexts (comorbidities with cardiac risk, and high-risk medications) were also analysed.

METHODS

Observational study with older adults (≥ 65 years) diagnosed with cancer, who were treated with antineoplastic agents (ANAs); it was conducted in three hospitals from the north of Portugal. Data collection was obtained using self-reports and medical records. DDIs were identified and classified using Micromedex® software. Descriptive and association analyze statistics were performed. Statistical hypothesis tests with p value less than 0.05 were considered significant. All statistical procedures and analysis were performed with R version 4.1.3.

RESULTS

We enrolled 552 patients. Polypharmacy prevalence was 88.40%; 76.45% and 56.16% of the patients presented with DDIs and SDIs, respectively. SDIs with ANAs were found in 21.20% of the patients. High-risk medications were associated with a higher risk of polypharmacy, DDIs, and SDIs. Polypharmacy and DDIs were higher in patients with hypertension or diabetes. SDIs were higher in patients with diabetes.

CONCLUSION

Polypharmacy, potential DDIs and SDIs were highly prevalent in older adults with cancer. A careful review of the medication administered is necessary to decrease it. These findings warrant further research to optimize medication in this population and decrease problems related to medication, which may lead to emergency room visits and hospitalisations, compromising patient safety and/or ongoing treatments.

Determination of drug-related problems in the hematology service: a prospective interventional study

BACKGROUND

Patients with hematological malignancies often require multidrug therapy using a variety of antineoplastic agents and supportive care medications. This increases the risk of drug-related problems (DRPs). Determining DRPs in patients hospitalized in hematology services is important for patients to achieve their drug treatment goals and prevent adverse effects. This study aims to identify DRPs by the clinical pharmacist in the multidisciplinary team in patients hospitalized in the hematology service of a university hospital in Turkey.

METHODS

This study was conducted prospectively between December 2022 and May 2023 in the hematology service of Suleyman Demirel University Research and Application Hospital in Isparta, Turkey. DRPs were determined using the Pharmaceutical Care Network Europe (PCNE) 9.1 Turkish version.

RESULTS

This study included 140 patients. Older age, longer hospital stay, presence of acute lymphoblastic leukemia, presence of comorbidities, higher number of medications used, and polypharmacy rate were statistically significantly higher in the DRP group than in the non-DRP group (p < 0.05). According to multivariate logistic regression analysis, the probability of DRP in patients with polypharmacy was statistically significant 7.921 times (95% CI: 3.033-20.689) higher than in patients without polypharmacy (p < 0.001).Every 5-day increase in the length of hospital stay increased the likelihood of DRP at a statistically significant level (OR = 1.476, 95% CI: 1.125-1.938 p = 0.005). In this study, at least one DRP was detected in 69 (49.3%) patients and the total number of DRPs was 152. Possible or actual adverse drug events (96.7%) were the most common DRPs. The most important cause of DRPs was drug choice (94.7%), and the highest frequency within its subcategories was the combination of inappropriate drugs (93.4%).

CONCLUSIONS

This study shows the importance of including a clinical pharmacist in a multidisciplinary team in identifying and preventing DRPs in the hematology service.

Assessment of potential drug-drug interactions in hospitalized cancer patients

INTRODUCTION

Drug-drug interactions (DDIs) pose a significant threat to patients with cancer, resulting in several adverse events in an oncology setting. Our study aims to identify potential DDIs in inpatient oncology wards, assess their severity, and provide recommendations to avoid these interactions.

MATERIALS AND METHODS

This prospective study was conducted in 79 hospitalized cancer patients over a period of 9 months (from August 2021 to May 2022) at the Amrita Institute of Medical Sciences, Kochi receiving at least two oncological or non-oncological drugs for 5 days.

RESULTS

Significant differences were found in drug count (61.6% vs. 38.4%), hospitalization duration (63.1% vs. 36.9%), and medications for comorbidities (63% vs. 37%) between patients with and without DDIs (p < 0.001, <0.001, and 0.01, respectively). The study identified 321 DDIs, with 14 (4.4%) X interactions, 93 (30%) D interactions, 161 (50%) C interactions, and 53 (15.6%) B interactions. Severity-wise, 76 (23.7%) were major, 190 (59.1%) were moderate, and 55 (17.2%) were minor.

CONCLUSION

Our study showed that drug count, medications for comorbidities, and hospitalization duration significantly increase the risk of DDIs in hospitalized oncology patients. Around 96.4% of recommendations for potential interactions were accepted and implemented, highlighting the huge opportunities and requirements for improvement, implementation, and management of drug interactions in oncology settings.

Drug-drug interactions of protein kinase inhibitors in chronic myeloid leukaemia patients: A study using the French health insurance database

The introduction of protein kinase inhibitors (PKIs) for chronic myeloid leukaemia (CML) has considerably improved prognosis of the disease but has also demonstrated a great potential for drug-drug interactions. Using the French health insurance databases, we aim to investigate the frequency, identify the associated factors and describe the potential consequences of potential drug-drug interactions (pPKI-DIs) between PKIs and concurrent medications in CML. A retrospective cohort study has been performed among patients with CML identified in the French healthcare database from 2011 to 2014. A pPKI-DI is defined as the presence of drugs listed as 'interacting' on the same day as PKI dispensing (co-dispensing) or in its coverage period (co-medication) during the first year of follow-up. The list of interacting drugs is based on the summary of products characteristics (SPCs) and Thesaurus of interactions. We performed specific nested case-control comparisons to investigate the association between PKI-DI and each of the three potential outcomes (death, hospitalisation for adverse drug reactions and switch to another PKI). We included 3480 patients; 1429 (41%) had a co-dispensing pPKI-DI, and 2153 (62%) had a co-medication pPKI-DI; 50% of the pPKI-DIs were 'to be taken into account', and 17% were 'not recommended'. The PKI with the most interactions was imatinib, and additional common drug classes included statins, benzodiazepines and proton pump inhibitors. Multivariate analysis demonstrated that the use of a higher number of additional drugs, comorbidities at baseline, high number of prescribers and higher ages were potential risk factors. Nilotinib and dasatinib showed a tendency towards a higher risk of pPKI-DI compared to imatinib. Despite the fact that some PKI-DIs were potentially clinically relevant, we did not find any significant association with death, hospitalisation for adverse drug reactions and switching. These findings should increase awareness to help reduce the prevalence of PKI-drug interactions and thereby ensure better management of CML patients.

Potential drug-drug interactions in patients with non-small cell lung cancer at a university hospital in Turkey

BACKGROUND

The aim of this study was to determine the drug profile of patients with non-small cell lung cancer (NSCLC) and to identify potential drug-drug interactions (PDDIs) during hospitalization. In particular, PDDIs in categories X and D were determined.

METHODS

This retrospective cross-sectional study was conducted in the oncology services of a university hospital between 2018 and 2021. PDDIs were evaluated using Lexicomp Drug Interactions® software included in UpToDate®.

RESULTS

A total of 199 patients were included in the study. Polypharmacy was present in 92.5% of the patients and the median (min-max) number of drugs used was 8 (2-16). 32% of the patients had D and X PDDIs. A total of 16 PDDIs at risk grade X were found in 15 (7.5%) patients. A total of 81 PDDIs of risk grade D were found in 54 (27.1%) patients and a total of 276 PDDIs of risk grade C were identified in 97 (48.7%) patients. Anticancer drugs (p = 0.008), opioids (p = 0.046), steroids (p = 0.003), 5-HT3 receptor antagonists (p = 0.012), aprepitant (p = 0.025) and antihistamines (p < 0.001) were statistically more frequent among patients with PDDIs than among those without.

CONCLUSION

The results of our study indicated that polypharmacy and PDDIs are common in hospitalized patients with NSCLC cancer. The monitoring of medications is critical for maximizing therapeutic effects and minimizing side effects related to PDDIs. As a part of multidisciplinary team, clinical pharmacists can contribute significantly to preventing, detecting and managing PDDIs.

Efficacy and tolerability of desvenlafaxine in the real-world treatment of patients with major depression: a narrative review and an expert opinion paper

INTRODUCTION

Major depressive disorder (MDD) is a common severe mental disorder, requiring a tailored and integrated treatment. Several approaches are available including different classes of antidepressants various psychotherapeutic approaches, and psychosocial interventions. The treatment plan for each patient with MDD should be differentiated on the basis of several clinical, personal, and contextual factors.

AREAS COVERED

Desvenlafaxine - a serotonine-noradrenergic reuptake inhibitor (SNRI) antidepressant - has been approved in the United States in 2008 for the treatment of MDD in adults, and has been recently rediscovered by clinicians due to its good side-effect profile and its clinical effectiveness. A narrative review on efficacy, tolerability and use of desvenlafaxine in clinical practice was carried out. The keywords: 'major depression', 'depression,' 'desvenlafaxine,' 'efficacy,' 'clinical efficacy,' 'side effects', 'tolerability,' 'elderly patients', 'consultation-liaison', 'menopausal', 'young people', 'adolescent' were entered in PubMed, ISI Web of Knowledge, Scopus and Medline. No time limit was fixed, the search strategy was implemented on May 10, 2023.

EXPERT OPINION

Desvenlafaxine should be listed among the optimal treatment strategies for managing people with MDD, whose main strengths are: 1) ease of dosing; 2) favorable safety and tolerability profile, 3) absence of sexual dysfunctions, weight gain and low rate of discontinuation symptoms; 4) low risk of drug-drug interactions.

Cytochrome P-450-mediated herb and food-drug interactions can be identified in cancer patients through patient self-reporting with a tablet application: results of a prospective observational study

BACKGROUND

Consumption of herbs, food used as medicine and dietary supplements (HFDSs) is common in cancer patients. Herbs and food-drug interactions (HFDIs) can lead to serious adverse effects and can be prevented. We previously reviewed cytochrome P-450 (CYP)-mediated HFDI for 261 HFDSs and we classified the risk of CYP inhibition and induction on a level of evidence scale from 1 (high evidence, supported by several clinical studies) to 5 (low evidence, only limited preclinical data).

PATIENTS AND METHODS

We conducted a prospective, non-interventional study (NCT04128865) to assess whether self-assessment of patients could detect HFDI classified as 'probable' (i.e. level 1, 2 or 3 of the scale) in a population of cancer patients. Patients were invited through a tablet application to report their consumption of herbs, regular CYP-interacting food consumption and dietary supplements, as well as some clinical data and cancer treatments. The patient's completion of the survey could be supervised by a health care professional or not. A prespecified threshold of 5% of HFDIs classified as 'probable' detected with the application was deemed relevant.

RESULTS

Between 29 March 2018 and 22 June 2018, 143 patients completed the survey. Ninety-five patients (66%) reported at least one current systemic cancer treatment and were included in the analyses. Seventy-four patients reported an intake of at least one HFDS (77.9%), while 21 patients reported no HFDS (22.1%). Twenty-two HFDIs classified as 'probable' were found in 16 patients (16.8%) with the application, which was significantly superior to the prespecified threshold (P = 0.02). The interactions were reported with food (n = 19, 86%) more frequently than with herbs (n = 3, 14%) or with dietary supplements (no interaction reported).

CONCLUSIONS

Self-assessment of HFDS interaction with cancer treatment with an application is feasible and should be considered in daily routine. Prospective interventional studies should be conducted to better assess the clinical benefits of this approach.

Frequency, severity, and factors associated with clinically significant drug-drug interactions among patients with cancer attending Mbarara Regional Referral Hospital Cancer Unit, Uganda

BACKGROUND

Cancer is a major public health problem with pharmacotherapy being the cornerstone of its management. Cancer patients receive multiple drugs concurrently risking Drug-Drug Interactions (DDIs). DDIs, though avoidable, can significantly contribute to morbidity, mortality, and increased healthcare costs in this population of patients. Currently, there is no published study from Uganda on clinically significant DDIs (cs-DDIs) among cancer patients. This study identifies frequency, severity, and factors associated with cs-DDIs at Mbarara Regional Referral Hospital Cancer Unit (MRRHCU).

METHOD

A cross-sectional study was conducted among 300 cancer patients receiving chemotherapy from a tertiary care hospital in western Uganda from January-February 2022. A questionnaire and data collection form were used to collect patient data. Lexicomp® Drug interaction software was used to screen the patient drug information for DDIs and assess their severity. Predictors of DDIs were identified using logistic regression using SPSS (Statistical Package for Social Sciences).

RESULT

Three hundred participants were enrolled with a mean age of 48 ± 23.3 years. One hundred eighty-one patients experienced 495 cs-DDIs; with a mean of 1.7 ± 2.2. The prevalence of cs-DDI was 60.3% (55.0-66.0% at 95% CI). Digestive organ neoplasms were the most commonly (80, 26.7%) diagnosed category, and 'plant alkaloids and other natural products were the most frequently (143, 47.7%) used chemotherapeutic drug classes. About three-quarters of cs-DDIs were rated as category C risk (367, 74.1%) whereas over two-thirds (355, 71.7%) were moderate in severity.. Being female (aOR = 2.43 [1.23-4.48 at 95% CI]; P-value = 0.011) and use of ≥ 6 drugs concurrently (aOR = 18.82 [9.58-36.95 at 95% CI]; P-value < 0.001)) were significantly associated with cs-DDIs.

CONCLUSION

More than half of the participants experienced at-least one cs-DDI which is generally higher than what was reported in high-income settings. About three-quarters were category C and moderate in severity, and require enhanced monitoring for safety and treatment outcome. Being female and using ≥ 6 drugs were significantly associated with cs-DDIs.

Association of Adherence to Endocrine Therapy Among Patients With Breast Cancer and Potential Drug-Drug Interactions

IMPORTANCE

Suboptimal adherence to endocrine therapy (ET) among patients with hormone-receptor-positive breast cancer significantly affects survival outcomes and is associated with higher hospitalization rates and health care costs. Weak adherence to long-term treatments has multiple determinants, including disease characteristics, treatment adverse effects, and patients' attributes, such as age and comorbidities.

OBJECTIVE

To examine whether potential drug-drug interactions (PDDI) with tamoxifen or aromatase inhibitor were associated with adherence to ET in patients with early and advanced breast cancer.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used anonymized health record data of women with breast cancer who received ET in a private observational primary care database. Patients eligible for analysis included women aged 18 years or older who had a reported diagnosis of breast cancer and received ET with tamoxifen or aromatase inhibitor between 1994 and 2021. Data were analyzed 2021.

EXPOSURES

Adherence to ET during a given year was defined by a medication possession ratio of 80% or greater over 1-year prescription periods. PDDI were categorized into absent, minor (a combination to take into account), moderate (combination requiring precautions for use), major (combination not recommended), and contraindicated according to guidelines in the Claude Bernard Drug Database.

MAIN OUTCOMES AND MEASURES

We used regression models to estimate odds ratios (ORs) and 95% CIs for the associations between adherence and age, baseline comorbidities, PDDI, and adherence to ET during the previous year.

RESULTS

A total of 10 863 patients who were prescribed ET for breast cancer were eligible for the analysis (age 70 years or older, 3509 patients [32.3%]). In the tamoxifen cohort (3564 patients), PDDI were reported in 497 of 3670 patients (13.5%) at baseline (moderate, 254 patients [51.1%]; major, 227 patients [45.7%]), 2047 of 4831 patients (42.4%) at year 1, 1127 of 2751 patients (41.0%) at year 2, 761 of 1861 patients (40.9%) at year 3, 376 of 1058 patients (35.5%) at year 4, and 201 of 593 patients (33.9%) at year 5. In the aromatase inhibitor cohort (7299 patients), PDDI were reported in 592 of 7437 patients (8.0%) at baseline (moderate in 588 of 592 patients [99.3%]), which reached 2875 of 9031 patients (31.8%) at year 1 and ranged between 31.4% (1802 of 5730 patients in year 2) and 32.8% (791 of 2411 in year 4) throughout the study period. No association between adherence and PDDI was found in the tamoxifen (OR, 0.99; 95% CI, 0.91-1.08) or aromatase inhibitor (OR, 1.05; 95% CI, 0.95-1.15) cohort.

CONCLUSIONS AND RELEVANCE

In this cohort of patients with hormone-receptor-positive breast cancer, PDDI with tamoxifen and aromatase inhibitors were not associated with adherence to ET.

Pharmacist Involvement in Cancer Pain Management: A Systematic Review and Meta-Analysis

This review aimed to critically evaluate the impact of pharmacist involvement in managing pain in cancer patients. Databases (including MEDLINE, Embase and CENTRAL) were searched with a broad search strategy for studies involving pharmacists and cancer pain management until February 10, 2021. The quality of studies and evidence were assessed using standardized tools and GRADE, respectively. A random-effects model was used for meta-analysis. Sixty-four studies were included. Common interventions delivered by the pharmacists were medication review, patient education, adverse drug reactions (ADRs) detection and management, pharmacological recommendations (in dosing and pharmacotherapy choice), and pain assessment. A pooled analysis of 3 randomized control trials showed a significant reduction in pain intensity with a standardized mean difference (SMD) of 0.35 [95% confidence intervals (CI): -0.55, -0.16]. Pooled analyses from nonrandomized studies of interventions also showed significant results in reduction of ADRs with an odds ratio of 0.69 (95% CI: 0.61, 0.79) and improvement in quality of life with SMD of 0.80 (95% CI: 0.29, 1.32). Thus, pharmacists significantly improve the clinical outcomes of cancer patients related to pain. This indicates the involvement of pharmacists directly or in collaboration with healthcare professionals in the oncology team is highly beneficial for the patients. PERSPECTIVES: This systematic review presents a comprehensive evaluation of pharmacist involvement in cancer pain management. This shows the importance of direct involvement of the pharmacist or as an important member of the multidisciplinary oncology team.

Comparison of different decision support software programs in perspective of potential drug-drug interactions in the oncology clinic

INTRODUCTION

One of the most intriguing situations for healthcare providers is cancer therapy. Drug-drug interactions (DDIs) account for 20-30% of all adverse effects. Cancer patients are more likely to have potential-DDIs since they are taking other drugs with anticancer treatments to prevent the side effects of chemotherapeutic agents. The purpose of this research is to compare various decision support software (CDSS) programs in terms of potential DDIs.

METHODS

A cross-sectional study was carried out. A clinical pharmacist assessed the treatment regimens of 231 cancer patients. pDDIs were evaluated using three sources: Lexicomp®, Medscape®, and Micromedex®. The ethical approval was given in November 2017 with decision number 21/286.

RESULTS

A total of 231 participants who were receiving therapy and had a median age of 61.5 ± 9.18 years were assessed. Almost half of the patients (49%) were female, and 155 had at least one comorbidity in addition to cancer. Medscape had a substantial pDDI ratio of 7.09%, Micromedex had a ratio of 11.15%, and Lexicomp had a ratio of 19.50%. The total number of pDDIs for major/X/contraindicated were 363-2716 (1.56-11.7 pDDI/patient) for Medscape®, 60-1723 (0.26-7.4 pDDI/patient) for Micromedex, and 145-984 (0.62-2.24 pDDI/patient) for Lexicomp®. One of the most common pDDI found was diclofenac and dexamethasone. Interactions between escitalopram and granisetron were also common, and different CDSSs made different recommendations.

CONCLUSIONS

In this study, significant disparities in the quantity and severity of CDSS across distinct CDSS were discovered. One of the major finding of our study was suboptimal prescribing. To address this issue, regulatory organizations should establish and verify validation and reporting mechanisms.

The Prevalence of Polypharmacy and Potential Drug-Drug Interactions among Iranian Cancer Patients: which Patients Were at Risk?

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, the present 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% CI: 53.6-66.0. Experience co-morbid diseases (OR:6.60; 95%CI: 3.82, 11.42; P-value ≤0.0001), and positive metastatic status (OR:2.80; 95%CI: 1.62, 4.82; P-value ≤0.0001) could predict the polypharmacy during chemotherapy courses. Patients who suffered gastrointestinal cancers (OR:5.55; 95%CI: 2.26, 13.62; P-value ≤0.0001) and the number of prescribed or Over The Counter (OTC) drugs (OR:1.29; 95%CI: 1.12, 1.48; P-value <0.0001) predicted the occurrence of potential DDIs among cancer patients.

CONCLUSION

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.

Megestrol acetate is a specific inducer of CYP3A4 mediated by human pregnane X receptor

PURPOSE

Megestrol acetate is a synthetic progestogen used to treat some cancers and cancer-associated cachexia, but its potential interactions with other drugs are not well known. This study aims to determine the regulation of drug metabolizing enzymes by megestrol acetate.

METHODS

Primary human hepatocytes were treated and analyzed by PCR array to identify genes involved in drug metabolism that are impacted by megestrol acetate. P450 3A4 (CYP3A4) reporter gene assay and HPLC analyses of nifedipine metabolites were used to determine CYP3A4 gene expression and activities. Competitive ligand binding assay was used to determine the affinity of megestrol acetate toward human pregnane x receptor (hPXR). Electrophoretic mobility shift assay and mammalian two hybrid assay were used to determine the mechanism of megestrol to activate hPXR.

RESULTS

The levels and activities of CYP3A4 were significantly induced (> 4-folds) by megestrol acetate in human hepatocytes and HepG2 cells. Megestrol treatment induced CYP3A4 through the activation of hPXR, a ligand-activated transcription factor that plays a role in drug metabolism and transport. Other tested nuclear receptors showed no response. The mechanism studies showed that megestrol activated hPXR by binding to the ligand binding domain (LBD) of hPXR and increasing the recruitment of the cofactors such as steroid receptor cofactor (SRC-1).

CONCLUSION

The results suggest that megestrol acetate is a specific inducer of CYP3A4 mediated by hPXR and therefore has the potential to cause drug interactions, especially in the co-administration with drugs that are substrates of CYP3A4.

Potential Cytochrome P450-mediated pharmacokinetic interactions between herbs, food, and dietary supplements and cancer treatments

Herbs, food and dietary supplements (HFDS), can interact significantly with anticancer drug treatments via cytochrome p450 isoforms (CYP) CYP3A4, CYP2D6, CYP1A2, and CYP2C8. The objective of this review was to assess the influence of HFDS compounds on these cytochromes. Interactions with CYP activities were searched for 189 herbs and food products, 72 dietary supplements in Web of Knowledge® databases. Analyses were made from 140 of 3,125 clinical trials and 236 of 3,374 in vitro, animal model studies or case reports. 18 trials were found to report direct interactions between 9 HFDS with 8 anticancer drugs. 21 HFDS were found to interact with CYP3A4, a major metabolic pathway for many anticancer drugs. All 261 HFDS were classified for their interaction with the main cytochromes P450 involved in the metabolism of anticancer drugs. We provided an easy-to-use colour-coded table to easily match potential interactions between 261 HFDS and 117 anticancer drugs.

Drug-drug interactions in subjects enrolled in SWOG trials of oral chemotherapy

BACKGROUND

Patients with cancer are at increased risk of drug-drug interactions (DDI), which can increase treatment toxicity or decrease efficacy. It is especially important to thoroughly screen DDI in oncology clinical trial subjects to ensure trial subject safety and data accuracy. This study determined the prevalence of potential DDI involving oral anti-cancer trial agents in subjects enrolled in two SWOG clinical trials.

METHODS

Completed SWOG clinical trials of commercially available agents with possible DDI that had complete concomitant medication information available at enrollment were included. Screening for DDI was conducted through three methods: protocol-guided screening, Lexicomp® screening, and pharmacist determination of clinical relevance. Descriptive statistics were calculated.

RESULTS

SWOG trials S0711 (dasatinib, n = 83) and S0528 (everolimus/lapatinib, n = 84) were included. Subjects received an average of 6.6 medications (standard deviation = 4.9, range 0-29) at enrollment. Based on the clinical trial protocols, at enrollment 18.6% (31/167) of subjects had a DDI and 12.0% (20/167) had a DDI that violated a protocol exclusion criterion. According to Lexicomp®, 28.7% of subjects (48/167) had a DDI classified as moderate or worse, whereas pharmacist review indicated that 7.2% of subjects (12/167) had a clinically relevant interaction. The majority of clinically relevant DDI identified were due to the coadministration of acid suppression therapies with dasatinib (83.3%, 10/12).

CONCLUSIONS

The high DDI prevalence in subjects enrolled on SWOG clinical trials, including a high prevalence that violate trial exclusion criteria, support the need for improved processes for DDI screening to ensure trial subject safety and trial data accuracy.

Clinical CYP2D6 Genotyping to Personalize Adjuvant Tamoxifen Treatment in ER-Positive Breast Cancer Patients: Current Status of a Controversy

Simple Summary

Tamoxifen is an important adjuvant endocrine therapy in estrogen receptor (ER)-positive breast cancer patients. It is mainly catalyzed by the enzyme CYP2D6 into the most active metabolite endoxifen. Genetic variation in the CYP2D6 gene influences endoxifen formation and thereby potentially therapy outcome. However, the association between CYP2D6 genotype and clinical outcome on tamoxifen is still under debate, as contradictory outcomes have been published. This review describes the latest insights in both CYP2D6 genotype and endoxifen concentrations, as well CYP2D6 genotype and clinical outcome, from 2018 to 2020.

Abstract

Tamoxifen is a major option for adjuvant endocrine treatment in estrogen receptor (ER) positive breast cancer patients. The conversion of the prodrug tamoxifen into the most active metabolite endoxifen is mainly catalyzed by the enzyme cytochrome P450 2D6 (CYP2D6). Genetic variation in the CYP2D6 gene leads to altered enzyme activity, which influences endoxifen formation and thereby potentially therapy outcome. The association between genetically compromised CYP2D6 activity and low endoxifen plasma concentrations is generally accepted, and it was shown that tamoxifen dose increments in compromised patients resulted in higher endoxifen concentrations. However, the correlation between CYP2D6 genotype and clinical outcome is still under debate. This has led to genotype-based tamoxifen dosing recommendations by the Clinical Pharmacogenetic Implementation Consortium (CPIC) in 2018, whereas in 2019, the European Society of Medical Oncology (ESMO) discouraged the use of CYP2D6 genotyping in clinical practice for tamoxifen therapy. This paper describes the latest developments on CYP2D6 genotyping in relation to endoxifen plasma concentrations and tamoxifen-related clinical outcome. Therefore, we focused on Pharmacogenetic publications from 2018 (CPIC publication) to 2021 in order to shed a light on the current status of this debate.

Use of Non-Cancer Medications in New Zealand Women at the Diagnosis of Primary Invasive Breast Cancer: Prevalence, Associated Factors and Effects on Survival

Background: Assessing the use of multiple medications in cancer patients is crucial as such use may affect cancer outcomes. This study reports the prevalence of non-cancer medication use at breast cancer diagnosis, its associated factors, and its effect on survival. Methods: We identified all women diagnosed with primary invasive breast cancer between 1 January 2007 and 31 December 2016, from four population-based breast cancer registries, in Auckland, Waikato, Wellington, and Christchurch, New Zealand. Through linkage to the pharmaceutical records, we obtained information on non-cancer medications that were dispensed for a minimum of 90 days’ supply between one year before cancer diagnosis and first cancer treatment. We performed ordered logistic regressions to identify associated factors and Cox regressions to investigate its effect on patient survival. Results: Of 14,485 patients, 52% were dispensed at least one drug (mean—1.3 drugs; maximum—13 drugs), with a higher prevalence observed in patients who were older, treated at a public facility, more economically deprived, and screen-detected. The use of 2–3 drugs showed a reduced non-breast cancer mortality (HR = 0.75, 95%CI = 0.60–0.92) in previously hospitalised patients, with other groups showing non-significant associations when adjusted for confounding factors. Drug use was not associated with changes in breast cancer-specific mortality. Conclusions: Non-cancer medication use at breast cancer diagnosis was common in New Zealand, more prevalent in older and disadvantaged women, and showed no effect on breast cancer-specific mortality, but a reduction in other cause mortality with the use of 2–3 drugs.

Prevalence of potential drug-drug interactions in breast cancer patients and determination of their risk factors

Breast cancer patients use numerous medications, which include cytotoxic chemotherapy drugs, hormonal agents and supportive medication, so they are more vulnerable to potential adverse drug interactions. This study aimed to evaluate frequency, severity, clinical importance and risk factors responsible for the Drug-drug interactions (DDIs) in a cohort of patients suffering from breast cancer. Data was obtained from 150 patients in the oncology ward (both inpatient and outpatient) with a confirmed diagnosis of breast cancer and currently receiving standard breast cancer-directed treatment. The data was recorded into a pre-designed form specifically made for this study through individual patient interviews and by reviewing the detailed medical chart records of the patients. DDIs were identified by using drug interaction software such as Medscape mobile application and Micromedex version 2.The results of this study showed that all patients were female. The mean numbers of drugs that patients used were 7. Potential drug interactions were identified in 92% of the patients. When drug groups were overviewed, 32% of interactions were between anti neoplastic drugs, 62.9% interactions were between the anti neoplastic agent and supportive care drugs and 5% of them were between anti-cancer drugs and drugs used to treat comorbidities. Major DDIs were found in 62.2% of patients, 25.3% of DDIs were moderate and 12.4% were minor. The number of drugs, comorbid diseases, and selection of chemo protocols were the risk factors for drug interactions. Most of the DDIs found in breast cancer therapy may have adverse consequences on patient health and therapeutic outcomes. Therefore, health care professionals should review the medication regimen of patients with breast cancer before starting any chemotherapy treatment.

Drug metabolism and pharmacokinetics of praziquantel: A review of variable drug exposure during schistosomiasis treatment in human hosts and experimental models

Schistosomiasis control is heavily reliant on the drug praziquantel (PZQ), which is used as preventive chemotherapy as part of national helminth control strategies. Given the heavy reliance on PZQ for mass drug administration, there has been considerable research on the potential of parasites developing resistance to the drug, resulting in decreased drug efficacy. However, there have been comparatively fewer studies of other factors that can potentially alter PZQ efficacy. Here, we investigate whether host PZQ metabolism contributes towards variable cure rates. We evaluate factors that can influence the metabolism of PZQ and the resultant effect on the efficacy of PZQ treatment to determine factors that potentially influence an individual's response to the drug. The literature search was directed at published studies from three online databases: Web of Science, PubMed, and EMBASE. The search terms for the review comprised of ([praziquantel OR PZQ] AND [schistosom* OR bilharzia] AND [pharmaco*]) and included studies evaluating PZQ metabolism. Publications were categorised into pharmacokinetics, drug-drug interactions, pharmacogenetics, and metabolite analysis. Forty publications describing human and experimental studies fitted the inclusion criteria and were subjected to data extraction and analysis. The analyses showed that variable exposure to PZQ was associated with alterations in the liver's capacity to metabolise PZQ and observed drug-drug interactions. Other factors influencing the efficacy of PZQ were brand, formulation, and co-administered food. Although some work has been performed on metabolite identification, there was minimal information on PZQ's metabolic pathway, and no pharmacogenetics studies were identified. The study indicated that in both human and experimental studies alterations in the liver's capacity to metabolise PZQ as well as drug-drug interactions affected systemic levels of PZQ that could result in variable cure rates. The study confirmed previous findings of higher antischistosomal activity of (R)-PZQ enantiomer when administered alone compared to the racemate at the same dose as well as improved efficacy when the drug is administered with food. The study also highlighted the need for more comprehensive studies of the PZQ metabolic pathway and PZQ pharmacogenetic studies in humans.

Hematologic adverse drug reactions leading to hospitalization among cancer patients: A retrospective case-control study

BACKGROUND

Cancer is one of the leading causes of death worldwide. Despite the rapid evolution of cancer treatment, chemotherapy remains the mainstay in the management of cancer. Chemotherapy can result in various adverse drug reactions (ADRs), which may lead to hospitalization and even life-threatening side-effects. Hematologic ADRs are among the most severe forms of ADR following chemotherapy, as they generally lead to hospitalization. It is important to realize the predictors and outcome of hematologic ADRs in cancer patients.

METHODS

We conducted a hospital-based case-control study to include all the cancer patients who were hospitalized to receive chemotherapy in Taipei Veterans General Hospital during 2013. Among them the patients rehospitalized after chemotherapy due to neutropenia, leucopenia, or pancytopenia were identified as the study group. Control subjects consisted of hospitalized cancer patients who did not display the aforementioned ADRs. The study and control groups were numbered in the ratio of 1:4 and were age- and gender-matched. Their demographic and clinical characteristics were collected through chart review. Determinants of hematologic ADRs were then analyzed.

RESULTS

During the study period, we collected a total of 64 patients into the study group and 256 as control subjects. The mean length of hospitalization was 11 days in the study group of patients, which was 5 days longer than that in the control group (p < 0.001). Predictors of hematologic ADR-related hospitalization included history of hematologic ADRs, hypertension, cisplatin treatment, and a Charlson comorbidity score of 2 to 3.

CONCLUSION

Severe outcomes of hematologic ADRs may increase healthcare costs and decrease patient productivity. Therefore, the determinants of ADR-related hospitalization identified in this study may help improve the quality of healthcare for cancer patients.

Considerations for interactions of drugs used for the treatment of COVID-19 with anti-cancer treatments

SARS-CoV2 infection is an emerging issue worldwide. Cancer patient are at increased risk of infection compared to general population. On the other hand, these patients are at major risk of drug interactions caused by renal and hepatic impairment background. Because of the long-term use of chemotherapy drugs, drug interactions are important in these patients especially with SARS-CoV2 treatments now. This paper is review of reported drug interactions of current treatments for COVID-19 and anticancer agents.

Effects of multidose simvastatin co-administration on pharmacokinetic profile of apatinib in rats by UPLC-MS/MS

Apatinib, a small molecule anti-angiogenic tyrosine kinase inhibitor is used extensively to treat advanced gastric cancer and simvastatin (SV) is often co-prescribed to treat cardiovascular disease in cancer patients. As both apatinib and SV are metabolized primarily by cytochrome P450 variant CYP3A4, they are likely to interact. Therefore, the potential effect of SV co-administration on pharmacokinetics of apatinib in Sprague-Dawley male rats is demonstrated for the first time.Sixteen rats were randomly divided into two groups (n = 8), 2 mg/kg SV orally co-administrated for seven days (group B) and the corresponding control group (group A). Apatinib concentrations of rat plasma samples were detected by ultra-performance liquid chromatography tandem mass spectrometry. Pharmacokinetic parameters were calculated using non compartmental methods.Co-administration of SV for seven days significantly increased area under curve (AUC_(0-t)), AUC_(0-∞) and maximum plasma concentration of apatinib by 2.4-, 2.4-, and 2.7-fold, respectively while decreasing apparent volume of distribution and clearance by 81.7 and 73.9%, respectively.These findings suggest that concomitant administration of SV with 7 days may have inhibited the metabolism of apatinib in rats.

Onco-cardiology: Drug-drug interactions of antineoplastic and cardiovascular drugs

Cardiovascular diseases (CVD) and cancer are still the leading causes of death. There are many common etiologic factors, especially smoking and obesity. Therefore, it is not uncommon for CVD and cancer to coexist. Drug-drug interactions (DDIs) inevitably occur in this group of patients, where polypharmacy is increasing due to older age and multiple comorbidities. However, multidisciplinary studies, especially close collaboration of medical oncologists and cardiologists, who deals with the diagnosis and treatment of these diseases, awareness and preventive approaches to DDIs may reduce serious morbidity and mortality. In this review, information about the common treatments used in cardiology and oncology and possible DDIs are discussed.

Factors associated with common mental disorders and use of psychiatric drugs in cancer outpatients

BACKGROUND

Considering the high incidence of cancer in Brazil and worldwide, the high prevalence and relevance of Common Mental Disorders (CMD) in the treatment of cancer patients, and the use of psychiatric drugs without reliably proven effectiveness, studies that contemplate this topic are needed to understand and provide rationale for the treatment of CMD in these individuals.

OBJECTIVES

This study identified prevalence and factors associated with Common Mental Disorders (CMD) and psychotropic use in cancer outpatients.

METHOD

This is a cross-sectional study with descriptive correlational design. It was developed in the chemotherapy sector of a hospital specialized in cancer. The tools used were: Self Reporting Questionnaire (SRQ-20) and structured questionnaires.

FINDINGS

Among 403 respondents, CMD prevalence was 31.5% and psychotropic use was 25.8%. CMD were associated with gender, education, family income, psychotropic use and cancer surgery. Psychotropic use was associated with gender, employment status, cancer surgery, treatment period and other physical health conditions. Logistic regressions showed CMD were associated with gender and other physical health conditions; psychotropic use was associated with gender, employment status and other conditions.

Prevalence of drug-drug interactions in oncology patients enrolled on National Clinical Trials Network oncology clinical trials

Background

Drug-drug interactions (DDIs) in subjects enrolling in clinical trials can impact not only safety of the patient but also study drug outcomes and data validity. This makes it critical to adequately screen and manage DDIs. The study objective was to determine the prevalence of DDIs involving study medications in subjects enrolling in National Clinical Trials Network (NCTN) clinical trials at a single institution. DDIs were evaluated based on study protocol recommendations for concomitant medication use (i.e. exclude, avoid or use caution), screening via DDI tool, and pharmacist review.

Methods

Subjects enrolled in NCTN trials of commercially available agents between January 2013 and August 2017 were included if a complete medication list was available. Complete medication lists were collected from the date of enrollment or the next available date then screened utilizing protocol guidance and the DDI screening tool, Lexicomp® Drug Interactions (Wolters Kluwer, Hudson, OH). Interactions were reviewed for clinical relevance: defined as a DDI that would require a medication change to ensure study agent safety and efficacy at enrollment.

Results

One hundred and twenty-eight subjects enrolled in 35 clinical trials were included. Protocol guidance detected 15 unique DDI pairs that should be avoided or used with caution in 10.2% (13/128) of subjects. The majority of these subjects did not have a clinically relevant DDI (69.2%, 9/13) based on pharmacist review. Lexicomp® detected moderate to major DDIs in 24.2% (31/128) of subjects, with 9.4% (12/128) having a clinically relevant DDI.

Conclusions

This study confirms a high prevalence of DDIs present in subjects enrolling in oncology clinical trials. Further efforts should be made to improve methods to detect and manage DDIs in patients enrolling on clinical trials to ensure patient safety and trial data validity.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5076-0) contains supplementary material, which is available to authorized users.

Patterns of medication adherence in a multi-ethnic cohort of prevalent statin users diagnosed with breast, prostate, or colorectal cancer

PURPOSE

To investigate the implications of a cancer diagnosis on medication adherence for pre-existing comorbid conditions, we explored statin adherence patterns prior to and following a new diagnosis of breast, colorectal, or prostate cancer among a multi-ethnic cohort.

METHODS

We identified adults enrolled at Kaiser Permanente Northern California who were prevalent statin medication users, newly diagnosed with breast, colorectal, or prostate cancer between 2000 and 2012. Statin adherence was measured using the proportion of days covered (PDC) during the 2-year pre-cancer diagnosis and the 2-year post-cancer diagnosis. Adherence patterns were assessed using generalized estimating equations, for all cancers combined and stratified by cancer type and race/ethnicity, adjusted for demographic, clinical, and tumor characteristics.

RESULTS

Among 10,177 cancer patients, statin adherence decreased from pre- to post-cancer diagnosis (adjusted odds ratio (OR_adj):0.91, 95% confidence interval (95% CI):0.88-0.94). Statin adherence decreased from pre- to post-cancer diagnosis among breast (OR_adj:0.94, 95% CI:0.90-0.99) and colorectal (OR_adj:0.79, 95% CI:0.74-0.85) cancer patients. No difference in adherence was observed among prostate cancer patients (OR_adj:1.01, 95% CI:0.97-1.05). Prior to cancer diagnosis, adherence to statins was generally higher among non-Hispanic whites and multi-race patients than other groups. However, statin adherence after diagnosis decreased only among these two populations (OR_adj:0.85, 95% CI:0.85-0.92 and OR_adj:0.86, 95% CI:0.76-0.97), respectively.

CONCLUSIONS

We found substantial variation in statin medication adherence following diagnosis by cancer type and race/ethnicity among a large cohort of prevalent statin users in an integrated health care setting.

IMPLICATIONS FOR CANCER SURVIVORS

Improving our understanding of comorbidity management and polypharmacy across diverse cancer patient populations is warranted to develop tailored interventions that improve medication adherence and reduce disparities in health outcomes.

Effects of medicines used to treat gastrointestinal diseases on the pharmacokinetics of coadministered drugs: a PEARRL Review

Objectives

Drugs used to treat gastrointestinal diseases (GI drugs) are widely used either as prescription or over-the-counter (OTC) medications and belong to both the 10 most prescribed and 10 most sold OTC medications worldwide. The objective of this review article is to discuss the most frequent interactions between GI and other drugs, including identification of the mechanisms behind these interactions, where possible.

Key findings

Current clinical practice shows that in many cases, these drugs are administered concomitantly with other drug products. Due to their metabolic properties and mechanisms of action, the drugs used to treat gastrointestinal diseases can change the pharmacokinetics of some coadministered drugs. In certain cases, these interactions can lead to failure of treatment or to the occurrence of serious adverse events. The mechanism of interaction depends highly on drug properties and differs among therapeutic categories. Understanding these interactions is essential to providing recommendations for optimal drug therapy.

Summary

Interactions with GI drugs are numerous and can be highly significant clinically in some cases. While alterations in bioavailability due to changes in solubility, dissolution rate, GI transit and metabolic interactions can be (for the most part) easily identified, interactions that are mediated through other mechanisms, such as permeability or microbiota, are less well-understood. Future work should focus on characterising these aspects.

The prevalence of major drug-drug interactions in older adults with cancer and the role of clinical decision support software

OBJECTIVES

Drug-drug interactions (DDIs) represent an escalating concern for older adults attributed to polypharmacy, multi-morbidity and organ dysfunction. Few studies have evaluated the prevalence of major DDIs and the variability between DDI detection software which confuses management.

MATERIALS AND METHODS

Prevalence of major DDIs was examined as a secondary analysis of outpatients aged ≥65 years. Demographic and clinical information was collected from electronic health records including age, sex, race, cancer type, comorbidities, and medications. All DDIs were screened by a clinical pharmacist using Lexi-Interact® and Micromedex®. Major DDIs were defined as Lexi-Interact® category D or X and/or Micromedex® category major or contraindication. Summary statistics of patient characteristics and DDIs were computed.

RESULTS

Our cohort included 142 patients (mean age, 77.7 years; 56% women, 73% Caucasian). The mean medications was 9.8 including 6.7 prescriptions, 2.6 non-prescriptions, and 0.5 herbals. Lexi-Interact® identified 310 major DDIs in 69% of patients (n = 98) with an average of 2.2 DDIs per patient. Micromedex® identified 315 major DDIs in 61% of patients (n = 87) with an average of 2.2 DDIs per patient. DDIs mostly involved opioids, antiplatelets, electrolyte supplements, antiemetics, and antidepressants. Variability existed with the severity rating reporting of the clinical decision support software.

CONCLUSIONS

There was a high prevalence of major DDIs in older adults with cancer. Utilizing clinical decision support software was beneficial for detecting DDIs however, variability existed with severity reporting. Future studies need to identify the relevant DDIs with clinical implications in order to optimize medication safety in this population.

Drug-drug interactions involving antidepressants: focus on desvenlafaxine

Psychiatric and physical conditions often coexist, and there is robust evidence that associates the frequency of depression with single and multiple physical conditions. More than half of patients with depression may have at least one chronic physical condition. Therefore, antidepressants are often used in cotherapy with other medications for the management of both psychiatric and chronic physical illnesses. The risk of drug-drug interactions (DDIs) is augmented by complex polypharmacy regimens and extended periods of treatment required, of which possible outcomes range from tolerability issues to lack of efficacy and serious adverse events. Optimal patient outcomes may be achieved through drug selection with minimal potential for DDIs. Desvenlafaxine is a serotonin-norepinephrine reuptake inhibitor approved for the treatment of adults with major depressive disorder. Pharmacokinetic studies of desvenlafaxine have shown a simple metabolic profile unique among antidepressants. This review examines the DDI profiles of antidepressants, particularly desvenlafaxine, in relation to drugs of different therapeutic areas. The summary and comparison of information available is meant to help clinicians in making informed decisions when using desvenlafaxine in patients with depression and comorbid chronic conditions.

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.

Explicit definitions of potentially inappropriate prescriptions of antibiotics in older patients: a compilation derived from a systematic review

Potentially inappropriate prescriptions (PIPs) of antibiotics (antibiotic-PIPs) are generally detected by applying implicit definitions based on expert opinion. Explicit definitions are less frequently used, even though this approach would enable the automated detection of antibiotic-PIPs in electronic health records. Here, explicit definitions of antibiotic-PIPs used in studies of older adults were systematically reviewed. The MEDLINE^®, Scopus^® and Web of Science^TM core collection databases were searched with a combination of three terms and their synonyms: 'potentially inappropriate prescription' AND 'antibiotic treatment' AND 'older patients'. Following standardised selection of publications, explicit definitions of antibiotic-PIPs were extracted and were classified into infectious diseases domains and subdomains. A total of 600 search queries identified 4270 records, 93 of which were selected for review. A total of 160 mentions of antibiotic-PIPs were found, corresponding to 62 distinct definitions in 19 infectious diseases domains. Nearly one-half of the definitions were related to upper respiratory tract infections (n = 11 definitions; 17.7%), lower respiratory tract infections (n = 8; 12.9%) and drug-drug interactions (n = 11; 17.7%). Almost 75% of definitions (n = 46) were mentioned in a single study only. Only three definitions concerned critically important antibiotics such as third-generation cephalosporins and fluoroquinolones. This systematic review identified 62 explicit definitions of antibiotic-PIPs. Most of the definitions were not found in more than one study and they varied in the degree of precision. We advocate the implementation of an expert consensus on explicit definitions of antibiotic-PIPs that correspond to today's challenges in public health.

Pilot Randomized Controlled Trial of Auricular Point Acupressure to Manage Symptom Clusters of Pain, Fatigue, and Disturbed Sleep in Breast Cancer Patients

BACKGROUND

Current management for a symptom cluster of pain, fatigue, and disturbed sleep in breast cancer patients has limited effects.

OBJECTIVE

The purposes of this prospective, randomized controlled pilot study were to (1) assess the feasibility and tolerability of auricular point acupressure (APA) intervention to manage pain, fatigue, and sleep disturbance in breast cancer patients and (2) provide an initial appraisal of effect size as compared with a control intervention.

METHODS

Thirty-one participants were randomized into either an active APA group (n = 16) or a control APA group (n = 15), which included the sham APA treatment not related to the symptoms. All participants received the APA once a week for 4 weeks. Self-report measures were obtained at baseline, weekly during intervention, at end of intervention, and at a 1-month follow-up.

RESULTS

For the 4-week of APA treatment, the retention rate was 88% for the active APA group and 73% for the control APA group. After 4 weeks of APA, participants in the active APA treatment had reported a reduction of 71% in pain, 44% in fatigue, 31% in sleep disturbance, and 61% in interference with daily activities. The control APA group experienced some moderate reduction in these symptoms.

CONCLUSION

Given that this was a pilot study with a small sample size, results must be interpreted with caution.

IMPLICATIONS FOR PRACTICE

Our results suggest that APA may provide an inexpensive and effective complementary approach for the management of symptom clusters for breast cancer patients, and further study is warranted.

Safety of Combined Treatment With Monoclonal Antibodies and Viscum album L Preparations

Combination strategies involving chemotherapy and monoclonal antibodies (mAb) are commonly used in attempts to produce better clinical outcomes. This practice has led to new and ongoing toxicities that may lead to reductions in dose or noncompliance, limiting the effectiveness of treatment. Viscum album L (VA) preparations are widely used in Europe as additive therapy and have been associated with reduced chemotherapy-related adverse reactions and increased health-related quality of life. Concomitant VA therapy might also reduce toxicity related to mAb. This retrospective study investigated the safety of combined treatment with VA and mAb in cancer patients. A total of 43 patients had combined therapy (474 exposures); 12 had VA without mAb (129 exposures), and 8 had mAb without VA (68 exposures). Most patients (89.3%) received concomitant chemotherapy or supportive therapies. A total of 34 patients (60.7%) experienced 142 adverse events (AEs). Leucopenia (14.1% of all events), acneiform rash (8.5%), and stomatitis (6.3%) occurred most frequently. Longitudinal logistic regression analysis suggested a nearly 5 times higher odds of experiencing an AE following treatment with mAb compared with mAb plus VA (95% CI = 1.53-16.14). Our results, together with theoretical consideration of potential botanical-drug interactions, suggest that combined treatment with VA and mAb is safe.

Potential drug-drug interaction in Mexican patients with schizophrenia

OBJECTIVE

The aim of this study was to observe potential drug-drug interactions in the medication of Mexican schizophrenic patients.

METHODS

We performed a retrospective and cross-sectional study that was carried out in a psychiatric clinic. Only the prescriptions of patients with schizophrenia whose diagnoses were based on the DSM-IV instrument were included in this study. The Drug Interactions Checker software ( http://www.drugs.com/drug_interactions.html ) was used in this study to analyse potential drug-drug interactions.

RESULTS

In total, 86 of 126 patients were at risk of potential drug-drug interactions. Haloperidol and biperiden was the most common drug pair of 232 pairs evaluated. In our study, 13.8% of drug-drug interaction showed a major level of severity, whereas in 83.2%, the interaction was moderate. Finally, central nervous system (CNS) depression and anticholinergic effect were the main possible effects of drug-drug interaction.

CONCLUSIONS

Our results revealed a high number of patients with schizophrenia receiving two or more drugs. The potential drug-drug interactions observed in the Mexican population are consistent with the concomitant use of antipsychotics, benzodiazepines, and antidepressants prescribed in schizophrenia that could cause central nervous system (CNS) depression and anticholinergic effect. Drug-drug interaction must be considered when the patient with schizophrenia is medicated.

CE: A Review of Common Oral Treatments for Breast Cancer: Improving Patient Safety in Nononcology Settings

: Breast cancer patients are living longer with the disease than ever before. According to the National Cancer Institute, more than 3 million women in the United States are currently living with a breast cancer diagnosis, and many seek care in nononcology settings, whether for treatment, acute symptoms and complaints related to their cancer diagnosis, or unrelated concerns. Yet many nononcology providers are unfamiliar with the various oral agents used to treat breast cancer, and their possible adverse effects and drug interactions. It is imperative that all providers be aware of these agents and know when a patient is currently taking or has taken them. This article provides an overview of the most common oral treatments for breast cancer and discusses common adverse effects and management.

The impact of comorbidity on cancer and its treatment

Answer questions and earn CME/CNE Comorbidity is common among cancer patients and, with an aging population, is becoming more so. Comorbidity potentially affects the development, stage at diagnosis, treatment, and outcomes of people with cancer. Despite the intimate relationship between comorbidity and cancer, there is limited consensus on how to record, interpret, or manage comorbidity in the context of cancer, with the result that patients who have comorbidity are less likely to receive treatment with curative intent. Evidence in this area is lacking because of the frequent exclusion of patients with comorbidity from randomized controlled trials. There is evidence that some patients with comorbidity have potentially curative treatment unnecessarily modified, compromising optimal care. Patients with comorbidity have poorer survival, poorer quality of life, and higher health care costs. Strategies to address these issues include improving the evidence base for patients with comorbidity, further development of clinical tools to assist decision making, improved integration and coordination of care, and skill development for clinicians. CA Cancer J Clin 2016;66:337-350. © 2016 American Cancer Society.

Metabolism-related pharmacokinetic drug-drug interactions with tyrosine kinase inhibitors: current understanding, challenges and recommendations

Drug-drug interactions (DDIs) occur when a patient's response to the drug is modified by administration or co-exposure to another drug. The main cytochrome P450 (CYP) enzyme, CYP3A4, is implicated in the metabolism of almost all of the tyrosine kinase inhibitors (TKIs). Therefore, there is a substantial potential for interaction between TKIs and other drugs that modulate the activity of this metabolic pathway. Cancer patients are susceptible to DDIs as they receive many medications, either for supportive care or for treatment of toxicity. Differences in DDI outcomes are generally negligible because of the wide therapeutic window of common drugs. However for anticancer agents, serious clinical consequences may occur from small changes in drug metabolism and pharmacokinetics. Therefore, the objective of this review is to highlight the current understanding of DDIs among TKIs, with a focus on metabolism, as well as to identify challenges in the prediction of DDIs and provide recommendations.

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

Background

When a patient concomitantly uses two or more drugs, a drug-drug interaction (DDI) can possibly occur, potentially leading to an increased or decreased clinical effect of a given treatment. Cancer patients are at high risk of such interactions because they commonly receive multiple medications. Moreover, most cancer patients are elderly and require additional medications for comorbidities. Aim of this preliminary observational study was to evaluate the incidence of well known and established DDIs in a cohort of cancer outpatients undergoing multiple treatments.

Methods

Anamnestic and clinical data were collected for 64 adult patients in the ambulatory setting with malignant solid tumors who were receiving systemic anticancer treatment.

Patients also declared all drugs prescribed by other specialists or self-taken in the previous 2 weeks. DDIs were divided into two different groups: ‘neoplastic DDIs’ (NDDIs), involving antitumoral drugs, and ‘not neoplastic DDIs’ (nDDIs), involving all other classes of drugs. The severity of DDIs was classified as major, moderate and minor, according to the ‘Institute for Pharmacological Research Mario Negri’ definition.

Results

About 34 % of cancer outpatients within our cohort were prescribed/assumed interacting drug combinations. The most frequent major NDDIs involved the anticoagulant warfarin (33 % of total NDDIs) that, in association with tamoxifen, or capecitabine and paclitaxel, increased the risk of haemorrhage. About 60 % of nDDIs involved acetylsalicylic acid.

Conclusions

Overall, 16 % of DDIs were related to an A-level strength of recommendation to be avoided. The lack of effective communication among specialists and patients might have a role in determining therapeutic errors. Our pilot study, although limited by a small cohort size, highlights the urgent need of implementing the clinical management of cancer outpatients with new strategies to prevent or minimize potential harmful DDIs.