Evaluation of Potential Drug-Drug Interactions (DDIs) Incidence in Critically ill Patients

Abstract

Objectives: We evaluated the instances of potential Drug-Drug Interactions (DDIs) in critically ill patients in a private care center, Mumbai, India and studied the factors associated with these. Methods: This is a secondary data analysis of 107 individuals from an intensive care unit in Mumbai, India. We used Medscape's multidrug interaction checker to identify and analyse the pattern of potential DDIs. We used the poison regression models for count outcomes to adjust for potential confounders (age, sex, co-morbidities). Key findings: The total number of interactions was 433 [41.4% (95% Confidence Intervals [CI]: 37.6%-45.6%)]. These interactions were highest in > 80 years (56.8%, 95% CI: 45.0%-70.8%). About 28% (95% CI: 25.4%-31.9%) interactions were classified as 'significant' and only 0.1% (95% CI: 0.0%-0.5%) were classified as 'contraindicated' interactions. The interactions were significantly higher in individuals with cardiovascular diseases (CVDs) (Rate Ratio [RR]: 1.86, 95% CI: 1.45, 2.41). Patients with diabetes mellitus (DM) were significantly less likely to have interactions affecting distribution (RR: 0.17, 95% 0.04, 0.77) and metabolism (RR: 0.38, 95% CI: 0.22, 0.65). Patients with renal disorders had significantly lower pharmacokinetic interactions (RR: 0.46, 95% CI: 0.23, 0.91). Conclusion: Though minor interactions were common, the proportion of contraindicated and serious interactions was low. Physicians, probably, were careful while prescribing medications to patients with DM, liver and renal diseases. However, this apparently was not the case in patients with CVDs. Thus, along with regular monitoring, it is important to train and advocate information about drug interactions with physicians of all specialties.