Objectives Optimal perioperative success in cardiac surgery requires precise management of drug treatment. This study aimed to determine the prevalence, types and associated factors of drug-related problems (DRPs) during the entire hospital stay.

Methods A prospective observational study was conducted at the department of cardiovascular surgery in a university hospital between November 2019 and March 2020. Patients with planned elective cardiac surgery, aged ≥18 years, were included. A clinical pharmacist collaboratively reviewed medications on a daily basis and identified DRPs.

Results A total of 100 patients (60 male) were included; median (range) age was 62 (19–86) years, and median (IQR) length of stay in hospital was 15 (9) days. A total of 275 DRPs were identified (median (IQR) 3 (2–4)). The number of patients who had at least one DRP was 47 preoperatively, 55 in the postoperative intensive care unit, 100 in the postoperative ward, and 16 at discharge. In order to reduce bias because of the small sample size, Firth’s logistic regression analysis was conducted. Statistically significant variables according to univariate analysis were included into a logistic regression model. Therefore the length of hospital stay (OR 1.14, 95% CI 1.03 to 1.26, p=0.008), living arrangements (living alone) (OR 4.24, 95% CI 1.41 to 12.73, p=0.009), number of medications at admission (OR 1.32, 95% CI 1.09 to 1.59, p=0.002), and having coronary artery bypass graft surgery (OR 2.87, 95% CI 1.07 to 7.70, p=0.03) were associated with an increased risk for DRPs in the final model.

Conclusion Hospital stay carries an increased risk for DRPs, especially at the postoperative stage. Modifiable risk factors for DRPs can be managed by required interventions performed by a multidisciplinary healthcare team.