Unfractionated heparin dosing nomograms: road maps to where?

Weight-adjusted nomograms have been a significant advance in the use of unfractionated heparin (UFH). Clinical trials have demonstrated the ability of weight-adjusted nomograms to achieve a therapeutic activated partial thromboplastin time (aPTT) more rapidly than with standard UFH dosing. Despite this advantage, a significant number of patients have subtherapeutic and supratherapeutic aPTTs. Real-world experiences also corroborate the inability to keep UFH therapeutic with the use of nomograms. Despite the limitations of UFH nomograms, they have been used in several different types of venous and arterial thrombosis treatment settings. Unfortunately, these nomograms are not all consistent and require a considerable amount of time for training health care professionals on their use in order to limit the potential for medication errors. Although UFH nomograms have provided advancement over standard UFH dosing, their limitations still generate the desire for a more predictable anticoagulant.