Background: Neuropsychiatric side effects of cardiac drugs such as nervousness, mood swings and agitation may be misinterpreted as symptoms of anxiety. Anxiety in cardiac patients is highly prevalent and associated with poor outcomes, thus an accurate identification is essential. The objectives were to: (I) describe the possible neuropsychiatric side effects of common cardiac drug therapies, (II) describe the use of cardiac drug therapy in cardiac patients with self-reported symptoms of anxiety compared to those with no symptoms of anxiety, and (III) investigate the association between the use of cardiac drug therapy and self-reported symptoms of anxiety. Methods: DenHeart is a large national cross-sectional survey combined with national register data. Symptoms of anxiety were measured by the Hospital Anxiety and Depression Scale (HADS-A) on patients with ischemic heart disease, arrhythmia, heart failure and heart valve disease. Side effects were obtained from ‘product summaries’, and data on redeemed prescriptions obtained from the Danish National Prescription Registry. Multivariate logistic regression analyses explored the association between cardiac drug therapies and symptoms of anxiety (HADS-A ≥ 8). Results: Among 8998 respondents 2891 (32%) reported symptoms of anxiety (HADS-A ≥ 8). Neuropsychiatric side effects were reported from digoxin, antiarrhythmics, beta-blockers, ACE-inhibitors and angiotensin receptor antagonists. Statistically significant higher odds of reporting HADS ≥ 8 was found in users of diuretics, lipid-lowering agents, nitrates, antiarrhythmics and beta-blockers compared to patients with no prescription. Conclusion: Some cardiac drugs were associated with self-reported symptoms of anxiety among patients with cardiac disease. Of these drugs neuropsychiatric side effects were only reported for antiarrhythmics and beta-blockers. Increased awareness about the possible adverse effects from these drugs are important.