Prevalence and Pattern of Drug-Drug Interactions in the Critical Care Units of a Tertiary Hospital in Alexandria, Egypt

INTRODUCTION: The complexity of the pharmacotherapy involved in the simultaneous use of several drugs and various therapeutic classes makes critically ill patients at an increased risk for DDIs. The objectives were to estimate the prevalence of DDIs in the critical care units (CCUs) at a main trtiary hospital, to analyze their clinical significance, onset, documentation and severity and to identify their possible determinants. METHODS:  Using a cross sectional design, 750 patients, admitted to the CCUs, whose medical prescriptions contain 4 or more drugs were included. A pre-designed structured questionnaire and a record review sheet were used to collect the following data: sociodemographic, smoking habits, medical history, long term used medications, the presence of hospital aquired infections, APAHE II score, length of stay, organ impairment, number of drugs per prescription and the number of prescribing physicians. Calculating the number of interactions for each patient was performed. The list of drugs for each prescription was analyzed using different software. RESULTS: The prevalence of DDIs among patients admitted to CCUs was 53.07%. The mean number of interactions occurred per patient was 2.98±1.91 interactions. The highest proportion of interactions had a significance number 1.0, possible and suspected documentation, delayed onset and moderate severity. Age of the patient and the number of prescribed drugs were the two independent factors found to be significantly affecting the prevalence of DDIs. CONCLUSIONS: Critically ill patients are at risk of DDIs and the patients’ age and the number of drugs prescribed increases this possibility.