(P-331) Evaluation of Potential Drug-drug Interactions Among Patients of the Nephrology and Kidney Transplant Wards of a Major Teaching Hospital

Background: A change in a drug's effect when the drug is taken with another drug is called drug-drug interaction(DDI). Chronic kidney disease (CKD) patients receive many medications for treating the underlying diseases leading to CKD or treating the common complications of CKD. DDIs due to polypharmacy are common in these patients.

Objectives: This study was aimed to find the prevalence of potential DDIs in patients and identify factors associated with these interactions.

Methods: This study was conducted for five months in 2017-2018 at the nephrology and kidney transplant ward of Razi hospital a teaching hospital, Rasht, Iran. All patients' medication regimen were screened for potential DDIs through Lexi-Interact® Online application. Each potential DDI was characterized based on severity, onset, mechanism, risk rating and reliability rating. The quality of patients' life was assessed with the Kidney Disease Quality of Life Instrument-SF36TM questionnaire. Logistic regression analysis was applied to identify the association of one or more DDIs with patients' clinical or demographic information. Initially, univariate logistic regression analysis was carried out. Then, for variables with significant univariate p-values, multivariate analyses were performed to identify risk factors associated with pDDIs. P-value <0.05 was considered statistically significant. SPSS version 24 was used for statistical analyses.

Results: The study included 191 patients (109 [57.07%] males) with a mean age of 58.09 ± 17.76 years. In the second analysis in transplant ward, the length of stay remained as an independent predictor in the model (beta=0.15, 95%CI: 1.55-3.12, P<0.001). The length of hospitalization explained only 11% of the potential DDIs variation. After removing the number of medications variable, hypothyroidism, age group, and stage of CKD were entered into the model in the second analysis of nephrology ward. Variation of these variables explained 24% of the potential DDIs variation. . More number of medications, hypothyroidism, lower age group, and higher stage of CKD were independently related to the more potential DDIs in the nephrology ward patients.

Conclusions: Potential DDIs are common in CKD patients so proper patient monitoring is essential for minimizing and preventing potential adverse outcomes of drug-drug interactions. Hospital pharmacists can play a critical role in improving treatment and reducing drug-related problems of hospitalized patients. Implementing the process of drug reconciliation by a trained pharmacist is recommended in order to detect DDIs as early as possible and minimize therapeutic failure and ADEs.