The Effect of Dried Aluminum Hydroxide Gel on the Blood Concentration of Cyclosporine-A

The blood concentrations of cyclosporine-A (CyA) decreased remarkably in a pediatric patient who had been administered CyA combined with dried aluminum hydroxide gel (DALG). The difference in the ratio of the dosage per body weight to the blood concentrations of CyA was remarkable in patients who underwent CyA immunosuppressive therapy either with DALG (n=25) or without DALG (n=21). The ratio was 15.6±8.9 (mean±standard deviation) in patients with DALG and 25.9 ±15.4 in those without DALG. After adding DALG to an in vitro pH 1.2 CyA solution, the solution became turbid and the concentration of CyA in the supernatant decreased by about 20 percent compared to the control without DALG. In rats, the area under the curve (AUC) of CyA with DALG was 17 percent lower than that of CyA alone. These findings indicate that the blood concentrations of CyA are affected by administration with DALG, and that aluminum hydroxide gel decreases the absorption of CyA by adsorption or complex formation.