Objective

Critically ill patients are at increased risk of drug-drug interactions but their prevalence and clinical relevance remains unclear. The prevalence of potential drug-drug interactions in an intensive care unit according to Micromedex Drug-Reax® and Lexi-Interact® databases was studied and the concordance between the two databases was assessed. In addition, drug-drug interactions detected in 2013 were compared with those identified in 2018 to determine updates between these years.

Method:

Between January and June 2013, 152 critical care patients were prospectively included. Cardiac patients were excluded. Demographic and clinical data together with the drugs administered on the first calendar day of intensive care unit admission were recorded. Potential drug-drug interactions were searched in both Drug-Reax® and Lexi-Interact® and their prevalence, level of severity and evidence were compared considering the same sample in 2013 and 2018.

Results:

In 2013, 1,025 potential drug-drug interactions were identified, corresponding to 438 unique pairs. Lexi-Interact® identified more interactions (92.8%) than Drug-Reax® (34.0%). The percentage of agreement between databases was 27.4%. The number of interactions included in both databases increased after the five years but their level of evidence decreased. The most common potential drug-drug interactions involved sedatives and analgesics, intentionally prescribed concomitantly. Only two potential drug-drug interactions were classified as contraindicated by both databases. None of the potential drug-drug interactions identified had a noticeable clinical impact. Neither did they imply a prescription change.

Conclusions:

This study shows that the prevalence of potential drugdrug interactions in the intensive care unit is high, although their clinical relevance is generally low. Our data also show a lack of concordance between Drug-Reax® and Lexi-Interact®, as well as their updates.