Medication reviews by emergency department pharmacists in patients hospitalised for an adverse drug event: a cost study.

OBJECTIVE: To perform a cost study of pharmacist-led medication reviews in patients with an acute hospitalization for adverse drug events. METHOD: Emergency department pharmacists performed medication reviews in patients hospitalized after visiting the emergency department for an adverse drug event (ADE). Control patients were hospitalized after an emergency department visit not related to an ADE and received usual care. The costs of the intervention were labour costs of the junior emergency department pharmacist and the cost savings consisted of costs of medication that was stopped or reduced during six months after the intervention. Sensitivity analyses were performed to evaluate different scenarios. RESULTS: In the intervention group (n = 104) 113 medication changes led to stopping or reducing medication, accounting for averted costs of €22,850. In the control group (n = 112) 39 medication changes led to stopping or reducing medication, accounting for averted costs of €299. The mean labour costs of the intervention were €138 per patient, resulting in saved costs of €61 per patient per six months. Sensitivity analyses showed that if the intervention would be performed by a senior clinical pharmacist, there are no cost savings (€-21), if parts of the intervention would be executed by pharmacy technicians (e.g. administrative tasks), cost savings would be augmented to €87, if outliers in costs associated with medication reduction would be excluded, there are no cost savings (€-35) and if the costs of reduced medication were extrapolated to one year, cost savings would be €260. CONCLUSION: In this study, medication reviews by junior emergency department pharmacists in patients hospitalized after an emergency department visit for an ADE lead to a cost reduction over a six month period. TRIAL REGISTRATION: The main study is registered on the ISRCTN registry with trial ID ISRCTN12506329 on 06-03-2022.

Therapeutic Drug Monitoring of Psychotropics as a Diagnostic Tool for CYP2D6 Poor Metabolizer Phenotype.

BACKGROUND: Interpatient variability in cytochrome P450 2D6 (CYP2D6) enzyme activity alters the serum concentrations of most psychotropics, which often have narrow therapeutic indices. Therefore, preemptive knowledge of CYP2D6 activity is desired. However, accessible indicators for deficient CYP2D6 activity are necessary because genotyping all patients prescribed CYP2D6 metabolized drugs is often not feasible or cost-effective. METHODS: In this study, the predictive value of the ratio between a CYP2D6 substrate and its metabolite, known as the metabolic ratio (MR), the dose-corrected serum concentration of substrate (CDR), and the dose-corrected sum concentration of substrate and metabolite (Sum CDR) of venlafaxine, risperidone, aripiprazole, and nortriptyline were determined to predict the CYP2D6 poor metabolizer (PM) phenotype. The area-under-the-receiver operator characteristic curve, as well as the sensitivity, specificity, and positive and negative predictive values of the optimal thresholds, were calculated. RESULTS: Although the MR, CDR, and Sum CDR all predicted the CYP2D6 PM phenotype, the predictive value of the MR was most robust for venlafaxine and aripiprazole, and the Sum CDR was inferior for all 3 psychotropics. MRs of venlafaxine, risperidone, and aripiprazole, and CDR of nortriptyline showed an area-under-the-receiver operator characteristics (95% confidence interval) of 97.2% (94.7%-99.6%), 93.0% (88.8%-97.2%), 97.8% (95.4%-100.0%), and 85.6% (78.0%-93.1%), respectively. Thresholds of the log(MR) of ≥0.1 for venlafaxine, ≥0.0 for risperidone, and ≥1.5 for aripiprazole, and log(CDR) ≥0.5 for nortriptyline produced >92% sensitivity and >64% specificity. CONCLUSIONS: If therapeutic drug monitoring is available, the thresholds presented here could serve as a diagnostic tool for the CYP2D6 PM phenotype of psychiatric patients prescribed the aforementioned psychotropic medications.