Abstract
The influence of a sodium citrate/citric acid mixture on the gastrointestinal (Gl) 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. AUC0-8 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 Gl 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.
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