Potential drug interactions with antibacterials in long-term care facilities analyzed by two interaction checkers

  • Matej Štuhec
  • Ines Potočin
  • Dora Stepan
  • Lea Ušaj
  • Marija Petek Šter
  • Bojana BeovićEmail author
Research Article


Background Residents in long-term care facilities take many medications concomitantly, including antibacterials, which increases the risk of drug–drug interactions. Objectives The aims of the study were to investigate the prevalence of severe potential interactions between antibacterials and other medications in Slovenian long-term care facilities and to compare the performance of two different drug–drug interaction checkers in these settings. Setting Residents in long-term care facilities in Slovenia. Method A point-prevalence study was conducted from April 2016 to June 2016. Residents’ characteristics, antibacterial treatment, and concomitant medications were obtained from their medical charts. Potential drug–drug interactions were determined using Lexicomp Online™ 3.0.2 and the online Drug Interactions Checker. The study only included potential drug–drug interactions categorized as type MA (major interactions) by the checker and as type X (should be avoided) by Lexicomp Online™. The study calculated the differences in the number of type X and MA potential drug–drug interactions between different antibacterial classes and between the two drug–drug interactions checkers. Main outcome measure Number of medications per patient, number of potential drug–drug interactions with antibacterial, and differences between two drug–drug interactions checkers. Results Eighty (68.4%) of Slovenian general long-term care facilities with 13,032 residents responded to the invitation. 317 (2.4%) of the residents received antibacterial treatment and 212 residents were included in the analysis. On average, they received 10.9 medications (SD = 3.9). Antibacterials were involved in 24.1% type MA potential drug–drug interactions and 26.4% type X potential drug–drug interactions. A significant difference in the total number of potential drug–drug interaction between the two checkers was found for all antibacterials, co-trimoxazole and fluoroquinolones (p < 0.005). Type X and MA potential drug–drug interactions were more common with fluoroquinolones than with beta-lactams or co-trimoxazole (p < 0.005). Conclusion Potential interactions between antibacterials, especially fluoroquinolones and other drugs, were common in long-term care facility residents treated with antibacterials. Differences in the number of potential drug–drug interactions between the two checkers indicate that if available the use of several sources of information is recommended in clinical practice. The results call for a collaborative approach to address the risks of drug–drug interactions.


Antibacterials Drug–drug interactions Interactions checkers Elderly Long-term care Slovenia 




Conflicts of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Matej Štuhec
    • 1
    • 2
    • 3
  • Ines Potočin
    • 1
  • Dora Stepan
    • 4
  • Lea Ušaj
    • 4
  • Marija Petek Šter
    • 5
  • Bojana Beović
    • 4
    • 6
    Email author
  1. 1.Faculty of PharmacyUniversity of LjubljanaLjubljanaSlovenia
  2. 2.Department for Clinical PharmacyPsychiatric Hospital OrmozOrmozSlovenia
  3. 3.Department of Pharmacology, Faculty of Medicine MariborUniversity of MariborMariborSlovenia
  4. 4.Department of Infectious Diseases, Faculty of MedicineUniversity of LjubljanaLjubljanaSlovenia
  5. 5.Department of Family Medicine, Faculty of MedicineUniversity of LjubljanaLjubljanaSlovenia
  6. 6.Department of Infectious DiseasesUniversity Medical Centre LjubljanaLjubljanaSlovenia

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