Low-molecular-weight heparins (LMWHs) are used to prevent clotting in hemodialysis extracorporeal blood circuits. In order to test the possibility of using reviparine (a LMWH of 3,900 D) in this indication, we studied the pharmacokinetics of the drug after a mean dose of 3,300 IU anti-Xa in 10 hemodialyzed patients. Reviparine was administered subcutaneously between two dialysis sessions and intravenously at the start of 20 dialysis sessions performed either with high (HP) or low-permeability (LP) membranes. We observed a moderate increase of the elimination half-life of reviparine (TV2: 5 ± 1.6 h between dialysis, 3.6 ± 1.3 during dialysis with an HP membrane and 4.7 ± 1.8 during dialysis with an LP membrane) versus 3.3 ± 1 in healthy volunteers. Dialysis procedures with an HP or an LP membrane do not importantly modify the pharmacokinetics of reviparin compared with data observed in healthy volunteers. During the sessions, we observed no clotting in the extracorporeal circuit, no hemorrhagic event and no prolongation of the fistula compression times. Further clinical studies are required to define the optimal dosage of reviparine to prevent coagulation in hemodialysis blood circu