The evaluation of potential drug-drug interactions with antibiotics in hospitalized patients.

Objective: Drug-drug interactions (DDIs) occur when one drug alters the effect of another drug. The aim of this study was to evaluate potential drug-drug interactions (pDDIs) associated with the use of systemic antibiotics in hospitalized patients.

Methods: The study included patients over the age of 18 who were hospitalized in our hospital on 12.07.2022 and were using at least two systemic drugs concurrently, with at least one being a systemic antibiotic. The study was conducted using the point prevalence method. The patients' medication was evaluated for pDDIs using the UpToDate^®/Lexicomp^® database system. According to this screening tool, pDDIs were classified into 4 groups according to their severity: B, C, D, and X, ranging from mild to severe.

Results: Out of the 296 patients included in the study, at least one pDDI was detected in 190 patients (64.2%). One hundred seventy-seven patients (59.8%) had at least one pDDI with non-antibiotic drugs. Fifty-seven patients (19.3%) had at least one pDDI with antibiotics. One hundred and six patients (35.8%) had no drug interactions. Patients with pDDIs related to antibiotics had significantly higher age, number of comorbidities, total number of medications and number of antibiotics (p=0.010, p=0.004, p<0.001, p<0.001, respectively) compared to patients without pDDIs related to antibiotics (n=239). For antibiotics, potential pDDIs were observed 25, 75, 6, and 6 times in groups B, C, D, and X, respectively. Out of the total of 398 antibiotics, penicillins (24.9%, n=99) and cephalosporins (24.4%, n=97) were the most frequently used. Respectively, eight and two pDDIs were detected with these drugs. While quinolones were used 47 times (11.8%), 74 pDDIs (59.7%) were identified with quinolones. Out of the 47 patients who used quinolones, 37 had pDDIs with antibiotics. The most frequent pDDI with antibiotics was associated with the use of quinolone systemic corticosteroids (15 patients). The second most prevalent interaction involves quinolone-angiotensin converting enzyme inhibitors or angiotensin 2 receptor blockers (13 patients).

Conclusion: Antibiotics should be checked for pDDIs before being prescribed. While beta-lactam antibiotics are generally considered safer in terms of pDDIs, greater caution should be exercised, particularly when prescribing quinolones.