Anabolic androgenic steroids (AAS), simply called "androgens", represent the most widespread drugs used to enhance performance and appearance in a sporting environment. High-dosage and/or long-term AAS administration has been associated frequently with significant alterations in the cardiovascular system, some of these with severe endpoints. The induction of a prothrombotic state is probably the most life-threatening consequence, suggested by numerous case reports in AAS-abusing athletes, and by a considerable number of human and animal studies assessing the influence of exogenous androgens on hemostasis. Despite over fifty years of research, data regarding the thrombogenic potential of exogenous androgens are still scarce. The main reason is the limited possibility of conducting human prospective studies. However, human observational studies conducted in athletes or patients, in vitro human studies, and animal experiments have pointed out that androgens in supraphysiological doses induce enhanced platelet activity and thrombopoiesis, leading to increased platelet aggregation. If this tendency overlaps previously existing coagulation and/or fibrinolysis dysfunctions, it may lead to a thrombotic diathesis, which could explain the multitude of thromboembolic events reported in the AAS-abusing population. The influence of androgen excess on the platelet activity and fluid-coagulant balance remains a subject of debate, urging for supplementary studies in order to clarify the effects on hemostasis, and to provide new compelling evidence for their claimed thrombogenic potential.
Keywords: AAS; anabolic androgenic steroids; androgens; hemostasis/haemostasis; platelet activity; platelet aggregation; platelet count; platelet reactivity; prothrombotic state; testosterone; thrombopoiesis; thrombosis; thrombotic diathesis.