Evaluation of Potential Drug-drug Interactions in the Prescriptions in Outpatient Settings

Introduction: Drug-drug interactions (DDIs) are an important component of drug-related adverse events, leading to morbidity and mortality worldwide. The aim of the present study was to evaluate the frequency and severity of potential DDIs (pDDIs) in the prescriptions written in outpatient primary care clinics in Trabzon, Turkey. Material and Methods: A retrospective descriptive study was carried out in 169 prescriptions from 15 primary care clinics. pDDIs were identified by using Lexi-Interact™ software program. Results: A total of 169 prescriptions involving 506 drugs were analyzed, of which 59 had at least one pDDI. The prevalence of pDDIs was 34.91%. The mean number of drugs per prescription was 2.99±1.08. A total of 124 pDDIs were identified with mean of 0.73±1.45 per each prescription. Hydrochlorothiazide was the most frequently prescribed drug involved in pDDIs (n=15, 12.10%). The most common pDDIs was between hydrochlorothiazide and metformin (n=4, 3.22%). The number of pDDIs are positively correlated with increasing age (r=0.33 p<0.01) and the number of prescribed drugs (r=0.41, p<0.01). The majority of pDDIs (n=96, 77.42%) were in the risk category C (monitor therapy). Conclusion: Our findings indicate that polypharmacy and age were associated with the risk of having pDDIs. Physicians and pharmacists should be aware of pDDIs to improve drug safety, patient compliance and, prevent adverse drug reactions. Analyzing of DDIs with softwares should be effective for management of risks associated with pDDIs.