Drug-drug interactions and potentially inappropriate medications among elderly outpatients

Atrianfar Fatemeh,Gholami Kheirollah,Rezaei Fatemeh,Javadi Mohammad Reza,Kargar Mona,Heidari Kazem

doi:10.1590/s2175-97902020000418728

Abstract

The high prevalence of concomitant chronic illnesses and the resulting higher number of medications in the elderly population increase the risk of adverse drug reactions due to drug-drug interactions (DDIs) and potentially inappropriate medications (PIMs). Therefore, the aim of this study was to investigate the prevalence and factors associated with DDIs and PIMs in outpatient geriatrics. In this cross-sectional study, 1512 prescriptions belonging to patients aged ≥65 years from five public pharmacies in Tehran were evaluated. Clinically relevant (C, D, and X) and significant DDIs (D and X) were documented according to the Lexicomp®. Additionally, Zhan criteria were used to detect PIMs. At least one clinically relevant DDI was detected in 61.7% of the prescriptions containing ≥2 medications. The largest percentage of prescriptions with DDIs was prescribed by cardiologists (74.3%). The number of medications in prescriptions and the specialty of the prescriber significantly affected both clinically relevant and significant DDIs in a logistic regression model. At least one PIM was identified in 16.3% of the prescriptions. General practitioners (GPs) were the largest prescribers of PIMs. The mean number of medications was significantly higher in prescriptions with PIMs. In conclusion, clinically relevant DDIs are frequent in the elderly. In terms of PIMs, more attention should be paid to the education of GPs.

Highlights

The population of geriatrics is increasing rapidly worldwide
This study was conducted to determine the prevalence and factors associated with drug-drug interactions (DDIs) and potentially inappropriate medications (PIMs) in a sample of elderly outpatient prescriptions
It was found that 61.7% of the patients who received at least two medications experienced a DDI

Summary

INTRODUCTION

The population of geriatrics is increasing rapidly worldwide. It is estimated that the global elderly population will increase from 12% of the total population in 2015 to 22% in 2050 (World Health Organization, 2017). Another important factor that plays a major role in the increased incidence of DDIs is visiting elderly patients by different physicians. The incidence of ADRs related to DDIs is significantly high in the elderly, most of which are clinically important (Obreli-Neto et al, 2012) These ADRs can eventually increase the cost of care, morbidity, and hospital stay (Fadare et al, 2016). Based on a systematic review, DDIs have a high prevalence (Nabovati et al, 2017) Another important issue in the pharmacotherapy of geriatrics is potentially inappropriate medications (PIMs). To double check the severity of the category X interactions, they were further investigated in “Drug Interaction Facts” published in 2014

Study design and sampling

RESULT

DISCUSSION

Findings

Limitation