Competitive sports eligibility, mandatory for the Italian law in all age classes, from young to master athletes, involves millions of subjects, who are at risk during their sport career both for prescription and illicit drugs (or banned substances included in the World Anti-Doping Agency list, annually updated). These drugs may interfere with adrenergic hyperactivation related to athletic activity and can bring to unfavorable cardiovascular effects, such as arrhythmias, coronary artery disease, myocarditis, pericarditis, heart failure, ion channel disease. Moreover, numerous compounds may reduce athletic performance. Cardiovascular side effects are more frequently reported when drug co-administration is performed, which occurs frequently. Drug co-administration may have a higher risk when a common metabolic pathway is used (i.e. P450 hepatic cytochrome), and inhibition or induction effects modify plasma drug levels. One of the most important problems remains for combination of drugs that might be torsadogenic. Therefore, it is mandatory to be aware of pharmacokinetic properties, mechanisms of action, side effects and interactions between drugs and competitive sports activities; moreover, possible clinical, instrumental (i.e. ECG) or laboratory markers should be pointed out in order to recognize a possible toxic effect and subsequently interrupt or modify drug administration and/or assumption.