Investigating Potential Drug-Drug Interactions in Pediatric and Adolescent Patients Receiving Chemotherapy.

Introduction: Pediatric and adolescent oncology patients admitted to receive chemotherapy are at risk for drug-drug interactions (DDI). While adult literature has quoted this risk to be as high as 95% of encounters, the literature in pediatrics is limited. This is a single-center, retrospective chart review of DDI in hospitalized pediatric oncology patients.

Methods: All patients admitted to Texas Children's Hospital for chemotherapy were included. Medications ordered during the hospitalization were evaluated by Lexicomp® Drug Interactions Tool. Interactions classified as D or X or interactions rated a C including a chemotherapeutic agent were independently reviewed by three clinicians for clinical relevance. Medications associated with central nervous system (CNS) depression or QTc prolongation were counted separately.

Results: Of 100 admissions evaluated, 100% had a flagged interaction. There were a total of 12 X-rated interactions, 8 D-rated interactions, and 12 C-rated interactions with a chemotherapeutic agent found to be clinically relevant. Thirty-three percent of admissions had 4 or more QTc prolonging medications ordered. Twenty-four percent of admissions had 3 or more prescribed CNS depressants. In total 49% of admissions were found to have at least 1 clinically-significant DDI.

Conclusions: This study exemplifies the risk of drug-drug interactions in children and young adults admitted to the hospital for chemotherapy. We demonstrated a high rate of flagged interactions with about half of admissions found to have a potentially clinically-significant DDI. Concomitant use of multiple QTc prolonging and CNS depressant medications was also prevalent, indicating a need to evaluate monitoring practices.