RT Journal Article SR Electronic T1 Effects of enzyme induction on metabolism of prednisolone. Clinical and laboratory study. JF Annals of the Rheumatic Diseases JO Ann Rheum Dis FD BMJ Publishing Group Ltd and European League Against Rheumatism SP 339 OP 343 DO 10.1136/ard.35.4.339 VO 35 IS 4 A1 Brooks, P M A1 Buchanan, W W A1 Grove, M A1 Downie, W W YR 1976 UL http://ard.bmj.com/content/35/4/339.abstract AB The addition of phenobarbitone in therapeutic dosage to the drug regimen of prednisolone-treated subjects with rheumatoid arthritis produced measurable deterioration in the clinical status of the patients associated with a more rapid clearance of prednisolone from plasma. It is considered that phenobarbitone induced the hepatic metabolism of prednisolone, effectively reducing the steady state plasma level and resulting in clinical relapse. A slight but significant improvement in the adrenocortical response to tetracosactrin (Synacthen) was noted after phenobarbitone therapy.