Evaluation of Drug Interactions in Hospitalized Patients with Malignancy

Drug-drug interaction (DDI) occurs when the pharmacological effect of a drug is altered due to concomitant administration with other drugs. DDIs still remain a serious issue; thus, we conducted this retrospective study to evaluate DDIs prevalence in our care center.

All admitted patients with any kind of malignancies that received at least two medications from oncology and non-oncology classifications during six months were enrolled in this study. All relevant data including, patients’ demographic information, diagnosis, hospitalization duration, and all administered medication during hospitalization were recorded. The DDI was assessed by using the latest version of Lexi-interact.

Each patient received a mean number of 11.6±4.7 medications. The number of non-oncology drugs demonstrated a remarkable correlation with the number of interactions (P<0.001).Whereas, the number of oncology drugs does not have any relation with the number of interactions (P=0.64). Among the 763 detected DDIs during this study, the incidence of major, moderate and minor interactions were 31.2%, 61.4%, and 7.3%, respectively.

Our results highlighted the clinical significance of DDIs, considering that 104 (92%) patients had at least one DDI. The main reason that could have potentially contributed to this outcome is the complicated nature of cancer treatment and clinical management. We believe that using computer software to collect all prescribed and OTC collaboration of clinical pharmacists with oncologists can reduce the potential interactions prior to drug administration.