[Drug-drug interactions in intensive care patients]

Abstract

Introduction: The purpose of this study was to investigate the frequency of potential drug-drug interactions (DDIs) within the first 24 hours of admission to an intensive care unit, and to determine which drugs were involved in potential DDIs along with the clinical relevance of the identified DDIs.

Methods: Drug data from all intensive care patients (n = 102) admitted during a three-month period in the spring 2007 were investigated. Potential DDIs were evaluated using the drug interaction system of Micromedex.

Results: Four patients were excluded because their treatment only included one drug. A total of 98 patients were treated with an average of ten drugs per patient. Among the enrolled patients, we found 242 potential DDIs, corresponding to an average of 2.5 DDIs per patient. The drugs most frequently involved in potential DDIs included antithrombotic drugs, opioids, loop diuretics, ACE inhibitors, beta blockers, NSAIDs, corticosteroids, quinolon antibiotics, cardiac glycosides, thiazide diuretics, -anaesthetics, antidepressants, anticonvulsants and sedatives.

Discussion: The number of DDIs per patient found in this study is high compared with the results of a recent Norwegian study. The majority of the identified DDIs were normal combinations of drugs, which are managed through monitoring of the patient and discontinuing of the offending drug if necessary. It is therefore important to revise the patient's medication daily.

Conclusion: A total of 71% of the 98 enrolled patients were exposed to one or more potential DDIs. We found an average of 2.5 potential DDIs per patient. Antithrombotic drugs, opioids and loop diuretics were most frequently involved in potential DDIs. The clinical relevance varied because the majority of the identified potential DDIs were normal drug combinations.