Immunosuppressive treatment policies. A) Glucocorticoids: absorption of prednisolone. I. The effect of fasting, food, and food combined with antacids.

Serum concentrations of prednisolone have been measured by radioimmunoassay in 19 healthy volunteers after ingestion of 20 mg prednisolone as four 5 mg tablets. Thirteen subjects were fasting, and 6 had taken a light breakfast. Repeat studies were performed with coadministration of antacid in the 6 non-fasting subjects. The maximum serum concentration of prednisolone was higher, (mean Cmax; fasting: 597 +/- 101 ng/ml, non-fasting: Cmax 489 +/- 56 ng/ml) and the rate of absorption more rapid in the fasting than in the non-fasting subjects (absorption t1/2 fasting: 15.7 +/- 7 minutes, non-fasting: 20 +/- 11.5 minutes). The extent of bioavailability of prednisolone and the rate of elimination were the same in both groups. In the non-fasting groups, the intake of antacid with the tablets had no significant effect on these parameters. This study shows that antacid may safely be coadministered with prednisolone tablets in non-fasting subjects without reducing the rate and extent of bioavailability of prednisolone. It is not known whether the reduction in maximum prednisolone concentration found when the tablets were taken after a meal has any clinical significance.