Elevated aluminum concentrations have been implicated in several disease states in the elderly. We examined the effects of sucralfate, a basic aluminum salt of sucrose sulfate, and ranitidine, administered individually and in combination, on plasma and urine aluminum concentrations in the elderly in a prospective, randomized, three-arm crossover study. Subjects were 20 healthy volunteers over age 65 years, with no clinically significant comorbidities or recent use of aluminum-containing drugs or histamine (H)2-antagonists. The three regimens were ranitidine 300 mg at bedtime, sucralfate 1 g 4 times/day, and ranitidine 300 mg at bedtime plus sucralfate 1 g 4 times/day, administered for 4 weeks, with a washout period of at least 1 week between regimens. Plasma and urine aluminum concentrations were measured on days 0, 1, 7, 14, and 28 of each regimen. After 28 days, mean plasma aluminum concentrations were significantly higher in subjects receiving sucralfate alone (8.5 +/- 1.8 micrograms/L) and sucralfate plus ranitidine (5.1 +/- 1.3 micrograms/L) compared with those receiving ranitidine alone (2.4 +/- 0.7 micrograms/L). Urine aluminum concentrations were significantly higher in subjects receiving sucralfate alone (133.2 +/- 32.8 micrograms/g creatinine) and sucralfate plus ranitidine (148.1 +/- 51.9 micrograms/g creatinine) compared with those receiving ranitidine alone (11.0 +/- 3.7 micrograms/g creatinine). There was no significant difference in plasma or urine aluminum concentrations between subjects who received sucralfate alone versus those who received sucralfate plus ranitidine. Sucralfate 4 g/day in elderly subjects produces a significant increase in both plasma and urine aluminum concentrations, compared with ranitidine 300 mg/day. This increase most likely is secondary to gastrointestinal absorption of aluminum in the sucralfate formulation. The clinical relevance of this increase requires further evaluation.
