Evaluation of drug-drug interactions and their clinical importance in a pediatric hematopoietic stem cell transplantation unit

Background and Aims: Many drugs with narrow therapeutic range and high toxicity risk are used in hematopoietic stem cell transplantation (HSCT) Units. The increase in the number of drugs raises the likelihood of interactions. This is particularly important in pediatric patients and may adversely affect the treatment process. In this study, we aimed to determine the potential drug interactions and to evaluate the clinical significance of them in terms of physician's and pharmacist's perceptions. Methods: The study was conducted as a prospective descriptive study over a six-month period in a tertiary care hospital's Pediatric HSCT Unit. A pharmacist evaluated inpatients' drugs for drug interactions by using a drug interaction checker program and the clinical significance of the interactions were evaluated by the physician and the pharmacist separately. Results: Drugs used in 20 patients (median age = 8 years, range = 0.6-17 years) were evaluated. A total of 525 potential drug-drug interactions were identified. Two hundred and forty seven interactions (47.05%) were major; 238 (45.33%) were moderate; 23 (4.38%) were contraindicated. The number of the interactions considered "clinically significant" by the pharmacist and "clinically insignificant" by the physician at the preparative regimen and post-transplant period were 15 (35.7%) and 37 (29.4%), respectively. Conclusion: The management of drug interactions is important in pediatric HSCT patients as a vulnerable group. Drug interactions should be interpreted according to the patient's clinical presentation, not only theoretically. Cooperation between physicians and pharmacists in the management of interactions will contribute to optimize the patient's treatment.