Single oral dose pharmacokinetics of the iron chelator deferiprone (L1) were studied in 24 patients with chronic iron overload and correlated with 24 h urinary iron excretion (UIE) and creatinine clearance. Absorption of L1 was rapid with a t1/2 of 22.2 +/- 17.7 (mean +/- SD) min. The elimination half-life (elt1/2) of the drug was 91.1 +/- 33.1 min and of its metabolite, L1-glucuronide (L1G) 147.7 +/- 52.0 min. Creatinine clearance of the patients correlated significantly with the elimination t1/2 of L1G (r = -0.79, P = 0.002). There was also a significant correlation between 24 h UIE in the 14 patients studied and L1 versus time area under the curve (AUC) (P = 0.007). The total amount of L1 recovered in urine in 24 h comprised 77.9 +/- 13.3% of the L1 dose. L1 efficiency (the 24 h UIE divided by the amount of iron the oral dose of L1 is capable of binding) in the 14 patients was 3.8 +/- 1.9%. These data show for the first time that the urinary elimination of L1G is influenced by the renal function of the patient. Although no significant accumulation of L1 and L1G will occur in most of the patients if L1 is given more than once daily, in some patients with impaired renal function, L1G may accumulate.