RESUMEN
Due to their effcacy and convenience, low-molecular-weight heparins (LMWH) are used as sustitutes of unfractionated heparin. Unfortunately, most of the evidence about safety and usefulness of LMWH have excluded patients with chronic kidney disease (CKD), in whom their elimination clearance is reduced, allowing an increased anticoagulant effect. Accordingly, there is a growing number of reports about major and fatal bleeding episodes in this group of patients using LMWH. At the present stage of knowledge, there is no defnitive cut-off value of renal function to adjust the doses or avoid the administration of LMWH, making their effects unpredictable in patients with CKD. Hence, it is reasonable to avoid the use of these drugs in patients with CKD, while awaiting for more evidence that supports their safer use.