Aluminum-citrate interaction in end-stage renal disease

The influence of a sodium citrate/citric acid mixture on the gastrointestinal (GI) absorption of aluminum (Al) from an Al(OH)₃ preparation was evaluated in six stable maintenance hemodialysis patients. Plasma Al concentrations were determined serially after each of the following treatment sequences (I) Al(OH)₃; (II) Al(OH)₃ + sodium citrate/citric acid; (III) sodium citrate/citric acid; (IV) Al(OH)₃ + NaHCO₃. AUC_0-8 for plasma Al from 0 to 8 hours was significantly greater (p < 0.05) for Al(OH)₃ + sodium citrate/citric acid (73 ± 23 μg · hr/l; mean ± SEM) than Al(OH)₃ (16 ± 30 μg · hr/l); sodium citrate/citric acid (-27 ± 14 μg · hr/l); or Al(OH)₃ + NaHCO₃ (6 ± 22 μg · hr/l). The 24 hour Al level remained above baseline (p < 0.03) following Al(OH)₃ + sodium citrate/citric acid (31 ± 12 (pre) vs 54 ± 14 μg/l (post), in contradistinction to study limb: I (34 ± 14 vs 30 ± 12 μg/l); III (79 ± 40 vs 65 ±35 μg/l); and IV (71 ± 37 vs 66 ± 42 μg/l). We conclude that the GI absorption of Al from Al(OH)₃ is enhanced by citrate in patients undergoing hemodialysis and that elevations of plasma Al persist longer. The concomitant administration of citrate and Al-containing phosphate (PO₄) binders should be avoided in patients with end-stage renal disease (ESRD). NaHCO₃ may serve as an alternative therapy for metabolic acidosis with less risk of enhancing Al absorption.