Are low-molecular-weight heparins safe in patients with chronic kidney disease? Due to their efficacy 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 definitive cutoff 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.

Renal failure secondary to effort rhabdomyolysis is uncommon. We report three males age 28, 37 (military sportsmen) and 44 years (sedentary obese), with this condition. Episodes occurred after a training session to run a triathlon, during the course of a mini marathon and during a rescue attempt of a drowning person. All three subjects experienced intense muscle symptoms, hemoglubinuria, oliguria, rise of blood urea nitrogen and a significant rise in muscle enzymes. Creatinekinase reached a maximum of 41 times normal, aspartate aminotransferase a maximum 35 times normal and lactacte dehydrogenase a maximum of 11 times normal. There was a rapid elevation of serum creatinine, reaching values of 6.6 and 9.8 mg/dl on the third day after the physical effort. This parameter had a disproportionate elevation in relation to urea nitrogen, in two subjects. All subjects were managed with saline hydration, sodium bicarbonate and furosemide. Only one required hemodialysis for two days. All normalized their renal function 18 to 48 days after the physical exertion. No subject had other predisposing conditions for acute renal failure.