Effective clearance of Ara-U the major metabolite of cytosine arabinoside (Ara-C) by hemodialysis in a patient with lymphoma and end-stage renal failure

Abstract

We report that hemodialysis clears Ara-U from the blood after high-dose Ara-C treatment in a patient with lymphoma and end-stage renal failure. The patient received two doses of Ara-C 1 g/m(2) 24 h apart and was hemodialyzed at about 6 h after each dose and subsequently as per her usual dialysis schedule. Multiple blood samples were collected after dosing. Blood and dialyzate were also collected from the dialysis circuit during a second identical treatment cycle. Ara-C and its metabolite Ara-U in plasma and dialyzate were measured chromatographically, and the data subjected to pharmacokinetic analysis. The distribution and elimination half-lives, steady-state volume of distribution and clearance values were 0.5 h, 7 h, 181 L and 307 l/h for Ara-C and 4.1 h, 34 h, 118 L and 2.64 l/h for Ara-U, respectively. The dialysis sessions immediately after the first and second doses cleared 39 and 52% (as Ara-U) of the respective Ara-C doses. Some 63% of Ara-U in plasma was extracted by dialysis. The patient showed no signs of neurotoxicity or other drug-related adverse effects. Hemodialysis is very effective in clearing Ara-U from the plasma in renal failure, and this maneuver could easily be used routinely to prevent Ara-U accumulation and minimize adverse effects in patients with renal failure.