Concurrent administration of antacids and prednisone: effect on serum levels of prednisolone.

1 Specific radioimmunoassays have been developed for the measurement of prednisolone and prednisone in serum. 2 Serum prednisolone levels have been measured following the administration of prednisone both with and without antacids. 3 There were no significant differences in the values of Cmax (mean +/- s.d.) (251 +/- 80 ng/ml with, 245 +/- 69 ng/ml without antacid), AUC (1430 +/- 469 ng ml-1 h-1 with, 1406 +/- 530 ng ml-1 h-1 without antacid) or Tmax (1.6 +/- 0.6 h with, 1.6 +/- 0.8 h without antacid). 4 Serum prednisone levels were less than 20% of prednisolone levels at all time intervals in the subjects studied. 5 Concurrent antacid administration has no significant effect on serum prednisolone levels attained.