Impact of Comorbidities and Drug Interactions in Patients With Metastatic Castration-Resistant Prostate Cancer Receiving Androgen Receptor Pathway Inhibitors.

PURPOSE: Androgen receptor pathway inhibitors (ARPIs) are widely prescribed in metastatic castration-resistant prostate cancer (mCRPC). Real-world frequencies and potential impacts of comorbidities and concomitant medication (conmed) interactions with ARPIs are not well described. METHODS: Patients receiving ARPIs for mCRPC were identified from the electronic Prostate Cancer Australian Database (ePAD). Demographics, clinicopathologic characteristics, and outcome data were extracted. Conmeds and comorbidities were collected from medical records. Potential interacting comorbidities were defined from trial and post-trial data. Clinically significant drug-drug interactions (DDIs) were identified using UpToDate Lexicomp and Stockley's databases. Patient characteristics, comorbidity interactions, DDIs, and outcomes were analyzed. RESULTS: Two hundred thirty-five patients received first- or second-line ARPIs for mCRPC from 2012 to 2021, with a median follow-up of 27 months. One hundred sixteen received abiraterone acetate (AAP) and 135 received enzalutamide (ENZ). The median age was 74 years, and the median number of conmeds was 4. Clinically significant DDIs occurred in 55 (47%) AAP patients and 90 (67%) ENZ patients. Only 5% of DDIs were predicted to affect ARPI pharmacokinetics (PK) or pharmacodynamics, whereas 95% were predicted to impact conmed PK or increase toxicity risk. In patients receiving ENZ, DDIs were associated with lower PSA50 (50% v 74%, P = .04) and poorer overall survival (28 v 45 months, P = .04), although statistical significance was not maintained on multivariate analysis. No significant survival differences were seen with DDIs in patients receiving AAP. Potential interactions between comorbidities and ARPI were present in 72% on AAP and 14% on ENZ with no significant associated survival differences. CONCLUSION: DDIs and drug-comorbidity interactions in real-world patients receiving ARPIs for mCRPC are common and may affect outcomes. Ongoing clinician education regarding DDIs is necessary to optimize patient outcomes.

The effect of an extended-hours ED clinical pharmacy service on admission medication prescribing errors.

OBJECTIVE: The aim of this study was to determine the effect of a 7-day extended-hours clinical pharmacy service in the ED on medication prescribing errors upon hospital admission and time to medication reconciliation. METHODS: In this retrospective observational study, high-needs patients reviewed by ED pharmacists were compared against those not reviewed, to determine if the service was associated with reduction in admission medication errors. The primary outcome was the rate of medication errors. Errors were independently rated by two senior clinicians using a risk-probability matrix. Secondary outcomes included service's impact on time to best possible medication history (BPMH) and medication reconciliation. RESULTS: There were 242 patients who met the inclusion criteria: 105 intervention vs 137 control. In the intervention arm, 74 patients had at least 1 medication error compared with 113 in the control arm (total errors 206 vs 407). The error rate per 10 medications (interquartile range) was 1.4 (0, 2.9) in the intervention arm compared with 2.7 (1.2, 4.3) in the control arm (risk ratio 0.66 [95% confidence interval: 0.56-0.78]; P < 0.001). There were 33 moderate-risk and no high-risk errors (intervention), compared with 84 moderate-risk and 3 high-risk errors (control). Percent agreement was 98.98% (weighted kappa: 0.62). Time to BPMH and medication reconciliation were reduced from 40.5 and 45.0 h to 7.8 and 40.0 h, respectively. CONCLUSIONS: The 7-day extended-hours ED clinical pharmacy service was associated with a reduction in medication prescribing errors in high-needs patients and improved time to BPMH and medication reconciliation.

A randomised controlled trial of clinical pharmacy intervention versus standard care to improve medication adherence in outpatients with head and neck cancer receiving radiotherapy.

PURPOSE: Patient understanding of medicines information and adherence to medication instructions are important variables for ensuring optimal cancer care. This randomised controlled trial (RCT) aimed to evaluate the impact of an outpatient clinical pharmacy service on medication adherence and symptom burden in cancer patients. METHODS: In this single-centre RCT, 115 patients were randomised 1:1 to a pharmacist-led pharmaceutical care program (intervention, n = 59) versus standard of care (control, n = 56) within an outpatient multidisciplinary radiotherapy clinic. The primary endpoint was medication adherence as assessed by Medication Understanding and Use Self-Efficacy (MUSE) scale and Teach-Back assessment. Secondary endpoints were patient-reported symptom burden assessed by the Edmonton Symptom Assessment Scale (ESAS). Patients were assessed at baseline (weeks 1-2) and at discharge from radiotherapy (weeks 5-7). RESULTS: Polypharmacy (use of five or more medications) was observed in 26% of patients at baseline compared to 97% at discharge. Patient self-efficacy and medication adherence was higher in the intervention arm compared to the control arm, with a mean MUSE score difference of 2.70 (95% CI 1.24, 4.17) after adjustment for baseline, and a higher proportion of patients with average Teach-Back score of four or more (86% vs 14%; odds ratio (OR) 46.09, 95% CI 14.49, 146.56). The mean (SD) scores for aggregate ESAS (0-100) at discharge were 26.2 (14.0) in the intervention arm and 32.0 (15.8) in the control arm demonstrating lower overall symptom burden associated with the intervention (mean score difference adjusted for baseline - 0.52; 95% CI - 1.03, - 0.01). CONCLUSION: A structured outpatient clinic pharmacy service significantly improved medication adherence and reduced overall symptom burden in patients receiving radiotherapy.

Radiation oncology outpatient medication management needs and service gaps - A cross-sectional study of patients and clinicians.

BACKGROUND: Patients receiving radiotherapy for the treatment of cancer can have complex medication requirements related to the management of side-effects and impaired swallowing ability. This study surveyed patients and clinicians to identify service gaps and unmet medication management needs. METHODS: Patient and clinician surveys were developed by a multidisciplinary team based on previously validated questionnaires. The patient survey focused on medication use and adherence. The clinician survey was based around a clinical case study and focused on identifying service gaps and practice variations. This survey was disseminated to radiation oncologists, pharmacists and nurses involved with the care of head and neck or lung cancer patients in Victoria. RESULTS: A total of 93 surveys were completed including 53 patient surveys and 40 clinician surveys. Radiotherapy patients reported high medication usage with up to 53% taking five or more medications daily. When asked the same set of questions relating to medication education requirements, patients receiving polypharmacy reported greater needs (72%) than recognised by the surveyed multidisciplinary clinician group (58%). They also reported a non-adherence rate of 46%. In addition, further disparities were identified in clinician practices and their approach to clinical situations which may result in conflicting advice and confusion for patients. CONCLUSION: While recognising deficiencies relating to the provision of medication information, oncologists, nurses and pharmacists underestimated patient needs for medication information, education and follow-up. Findings support the rationale for integration of pharmacy services within the radiotherapy clinics to support patient care and bridge service gaps relating to medication management.

A systematic review of the impact of outpatient clinical pharmacy services on medication-related outcomes in patients receiving anticancer therapies.

BACKGROUND: Patients receiving anticancer therapies are frequently prescribed complex and high-risk medication regimens, which at times can result in medication misadventures. The objective of this review was to assess the effect of outpatient clinical pharmacy services on medication-related outcomes in patients receiving anticancer therapies, including patients undergoing radiotherapy. METHODS: A systematic review of original publications indexed in EMBASE, MEDLINE and Cochrane Library from June 2007 to June 2017. Eligible studies evaluated outpatient pharmacy clinic services for cancer patients and reported at least one medication-related quantitative outcome measure. Two authors independently reviewed full-text articles for inclusion, then extracted data and performed quality and risk of bias assessments. RESULTS: Of 908 identified publications, 13 met predefined eligibility criteria; 1 randomised control trial, 2 controlled cohort studies and 10 uncontrolled before-after studies. Many excluded studies described outpatient pharmacy services but lacked medication-related outcomes. All included studies had informative practice model designs, with interventions for drug-related problems including drug dose optimisation ( n = 8), reduced drug interaction ( n = 6) and adverse drug reaction reporting ( n = 3). Most studies ( n = 11) reported on symptom improvement, commonly nausea ( n = 7) and pain ( n = 5). Of four studies in radiotherapy cohorts, pharmacist involvement was associated with improved symptoms, satisfaction and wellbeing scores. CONCLUSION: Few studies have objectively assessed outpatient pharmacy cancer services, even fewer in the radiotherapy settings. Although the results support these services, significant heterogeneity and bias in the study designs prohibit robust conclusions and further controlled trials are required.

Failure to achieve therapeutic levels with high-dose posaconazole tablets potentially due to enhanced clearance.

Aim To describe a case of persistent sub-therapeutic posaconazole levels in setting of salvage chemotherapy for relapsed acute myeloid leukemia. Case details A 57-year-old male was admitted for the management of relapsed acute myeloid leukemia and ongoing pulmonary aspergillosis. While continuing on posaconazole tablet 300 mg daily, he received a course of salvage chemotherapy. The initial steady state posaconazole trough level was therapeutic at 0.84 mg/L (target >0.70 mg/L). However, after five days, the level had dropped to 0.40 mg/L, coinciding with hyperbilirubinemia and hypoalbuminemia. Bilirubin level peaked at 36 µm/L (normal high <20 µm/L), albumin levels were consistently low, averaging at 25 g/L (range 33-46 g/L). The patient had been compliant and there were no underlying gastrointestinal conditions identified which might have potentially affected posaconazole absorption. Outcome An increase in posaconazole dose failed to achieve target levels and treatment was changed to voriconazole. However, levels were surprisingly supra-therapeutic, resulting in side effects and substantial dose reduction was required. Conclusion Failure to achieve target posaconazole levels despite increased dosing may be attributed to factors other than impaired oral absorption. Enhanced metabolism and clearance could be associated with hypoalbuminemia and hyperbilirubinemia. Further case studies, including PK modelling, are required to confirm this effect.