Impact of Clinical Pharmacist-Led Interventions on the Interception of Medication Errors and Error-Related Toxicity in Pediatric Oncology Patients

Background: Pediatric oncology patients are highly susceptible to medication errors, because chemotherapeutic agents are high-alert drugs with a narrow therapeutic index requiring individualized, weight-based dosing. Prospective intervention-based evidence from resource-limited settings is scarce. This study evaluated the effect of clinical pharmacist interventions on medication errors in pediatric oncology inpatients. Methods: In a prospective pre-post study in the central teaching hospital of pediatrics in Baghdad, Iraq (September 2025-April 2026), 125 patients receiving high-alert medications were included. Errors were identified from medical records, graded by the National Coordinating Council for Medication Error Reporting and Prevention (NCC MERP) index, and compared before and after clinical pharmacist intervention. Changes were analyzed with Wilcoxon signed-rank and exact McNemar tests, and baseline differences with Kruskal-Wallis and Mann-Whitney U tests ( P ≤ .05). Results: All 125 patients had ≥1 baseline error (median 4 [IQR 3-6]); dose errors were most common (52.8%) and a missing intravenous-flush order universal (100%). After pharmacist review, errors were intercepted and corrected, leaving 123 of 125 patients (98.4%) error-free (median 0; P < .001), with two residual errors. All errors linked to toxicity (14.4%) or therapeutic failure (1.6%), and all grade E and F events, were eliminated. Physicians accepted 541 of 567 (95.6%) recommendations. Conclusions: Embedding a clinical pharmacist substantially reduced medication errors, with near-universal physician acceptance. Because the same pharmacist identified and corrected the errors, these findings reflect real-time interception rather than durable prevention; sustainability warrants controlled evaluation. The results nonetheless support routine clinical pharmacist integration in pediatric oncology, particularly in resource-limited settings.