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CP-051 Evaluation of electronic drug interaction checker databases – rheumatoid arthritis patients case study
  1. T Laptos,
  2. P Volk Markovic,
  3. A Cufar
  1. University Medical Center Ljubljana, Pharmacy, Ljubljana, Slovenia


Background Due to sometimes difficult pharmacological management of the disease and comorbidities, patients with rheumatoid arthritis (RA) are often subjected to multi-drug treatment. Electronic databases with drug interaction checker functions can be a useful tool to predict potential drug-drug interactions; however the descriptions may not always be supported by adequate data.

Purpose To evaluate the validity and appropriateness of drug-drug interaction descriptions of a commercial and an open-access database.

Material and methods The medical records of 25 patients receiving 5 or more medicines (N = 8,64 ± 1,95) were analysed. The majority (84%) were receiving methotrexate and 16% were on additional biological treatment (adalimumab, etanercept or tocilizumab).

Lexi-comp and databases were used to identify potential interactions. The descriptions rated D (N = 26) or X (N = 1) (Lexi-comp) or Major (N = 21) ( were reviewed. The interaction descriptions were classified as either (1) appropriate (data based on primary sources and/or medicinal products’ SmPCs), (2) undefined (general descriptions including multiple drugs or inconclusive data) or (3) inappropriate (data not corroborated by primary sources or misinterpreted).

Results The Lexi-comp and descriptions of interaction were deemed “appropriate” (63 vs. 48%), “undefined” (26 vs. 33%) and “inappropriate” (11 vs. 19%) respectively. The majority of “undefined” classifications were describing class effects. The overestimation of biologicals and methotrexate interactions (even though concomitant use is recommended by current guidelines) was the main cause for “inappropriate” classifications.

Conclusion The databases with interaction checker functions provide a powerful tool for a pharmacist when reviewing the patient’s treatment. Nevertheless, in patients with RA, due to simultaneous use of a variety of immunomodulatory drugs, the databases tend to overestimate the class effect of those medicines. Our data shows that only about one half (56% overall) of potential interactions described in them can be classified as “appropriate”. It is therefore crucial that the pharmacist’s final decision is based on clinical data.

References and/or Acknowledgements Professional advice of R. Antolic, MSc is highly appreciated

No conflict of interest.

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