The Narrow Therapeutic Index of Thrombin Inhibition: Implications for Newer Antithrombotic Therapies.

Recent trials have compared direct thrombin inhibitors with heparin as adjunctive therapy with thrombolysis for acute myocardial infarction or as antithrombotic therapy following coronary angioplasty. The results suggest that these agents are comparable to heparin in terms of efficacy, and can be safely administered; however, like that of heparin, the therapeutic index of direct thrombin inhibitors is narrow. Thus, one must excercise caution in trial design and data interpretation from studies of these antithrombotic agents in patients with acute coronary syndromes. The potential applicability of these agents to patients with acute coronary syndromes, the appropriate dosing regimen, and the patient population in whom the therapeutic index is optimal all await further study.