Angiotensin-converting enzyme. Investigation of diurnal variation, the effect of a large dose of prednisolone, and prednisolone pharmacokinetics in patients with sarcoidosis.

Abstract

Serial assay of serum angiotensin-converting enzyme concentrations (SACE) is advocated for monitoring disease progress in sarcoidosis. Because little is known of nondisease factors affecting SACE, 10 patients with histologically proved sarcoidosis were assessed for diurnal fluctuation in SACE and as to whether a large dose of corticosteroid had an immediate effect on SACE independent of disease. The pharmacokinetics of prednisolone in 8 of these patients was also evaluated. On Day 1, serum samples were obtained for 24 h after placebo, and the next day at the same times after 75 mg of orally administered prednisolone. There was no obvious diurnal pattern on either day, and there was no significant difference in SACE after prednisolone. The mean maximal difference obtained within or between days was 8.8%. Prednisolone pharmacokinetics were comparable to normal volunteers. SACE concentrations can be confidently determined at any time of day, and changes of greater than 9% are probably significant. The use of prednisolone in patients with sarcoidosis can be safely based upon pharmacokinetic data obtained from normal volunteers.