With increasing numbers of older adults worldwide, multimorbidity and polypharmacy are on the rise, highlighting the risks of harmful drug-drug interactions (DDIs) to patients. As cardiovascular agents are among the most prescribed medications, we performed an observational cross-sectional study to determine the prevalence of DDIs in a cardiology department of a secondary hospital. Patient data was obtained from medical records and screened for DDIs using the Micromedex drug interaction software. Descriptive statistics, Chi-square (χ2) test, Student's t test and Pearson's correlation test were used to analyse the results. Out of 50 participants, 45 (90%) had at least one DDI. A total of 266 DDIs were identified, with more than half classified as major. At least one major DDI was found in 78% of patients. 42% of patients were at an increased risk of bleeding due to DDIs. A statistically significant relationship was found between the detection of DDIs and both patient age (p = 0.005) and the number of drugs used (p < 0.001). Our findings pose questions about the wider prevalence and risks of drug-drug interactions among patients with cardiovascular disease.