Adverse side effects of drugs are a significantly underestimated problem in modern medicine. In this review article, we summarize common adverse side effects of cardiovascular drugs. In particular, we highlight the factors promoting these adverse side effects in patients, including reduced hepatic or renal clearance in elderly patients that often requires dosage adjustment. Pharmacodynamic and pharmacokinetic interactions between drugs (e.g. through the cytochrome P450 system or P-glycoproteins) can modify the plasma concentration of many compounds, thereby also increasing the likelihood of unwanted side effects. The most prominent cardiac side effects include arrhythmias, e.g. atrioventricular (AV) block, drug-induced long-QT syndrome and torsade de pointes and altered inotropy. Non-cardiac side effects are subsequently discussed grouped by drug class. A better understanding of the risks and side effects of cardiovascular drugs is expected to reduce the mortality and morbidity associated with adverse side effects.