Decreased bioavailability of prednisone due to antacids in patients with chronic active liver disease and in healthy volunteers.

To investigate the potential action of antacids on prednisone absorption and on prednisolone serum levels, we studied 5 healthy volunteers and 12 patients with chronic active liver disease. Six patients responded to treatment and 6 did not. After administering two 5-mg tablets of prednisone with 60 ml of water, 60 ml of Melox (AlOH 3.75 g/100 ml + MgOH 4.0 g/100 ml), or 60 ml of Aldrox (AlOH 8.0 g/100 ml + MgOH 1.95 g/100 ml), we measured prednisolone by radioimmunoassay. Both peak heights and areas under the serum-concentration curves were significantly reduced when prednisone was administered with antacids. The relative bioavailability of prednisone after prednisone-antacid treatments compared to that after prednisone-water treatment was 74% +/- 13% (p less than 0.05) with Melox and 57% +/- 15% (p less than 0.01) with Aldrox in healthy volunteers. In patients with chronic active liver disease responding to treatment, prednisone bioavailability was 65% +/- 120% (p less than 0.01) and 87% +/- 20%, respectively. Among patients with chronic active liver disease not responding to treatment, this parameter was 76% +/- 12% (p less than 0.05) and 80% +/- 21% (p less than 0.05), respectively. To insure adequate prednisolone levels in patients with chronic active liver disease, prednisone should not be given simultaneously with antacids.