Premium
Effects of cimetidine and ranitidine on the conversion of prednisone to prednisolone
Author(s) -
Sirgo Mark A,
Rocci Mario L,
Ferguson Roger K,
Eshelman Fred N,
Vlasses Peter H
Publication year - 1985
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1985.84
Subject(s) - cimetidine , prednisolone , prednisone , medicine , ranitidine , pharmacology , endocrinology , placebo , corticosteroid , urine , pharmacokinetics , volume of distribution , oral administration , chemistry , alternative medicine , pathology
Prednisone is a glucocorticoid that must be converted in vivo to prednisolone for pharmacologic activity. We examined the effects of the H 2 ‐receptor antagonists cimetidine and ranitidine on the time course of plasma prednisolone concentrations after an oral dose of prednisone. Nine healthy men received each of three oral treatments in a double‐blind, balanced, crossover manner: cimetidine (300 mg every 6 hours), ranitidine (150 mg twice a day), or placebo for 4 days, with prednisone (40 mg) taken also on day 4. Serial blood and urine samples were collected for 30 hours after prednisone dosing. Prednisone and prednisolone plasma and urine concentrations were analyzed by HPLC. No differences were found between treatments in the maximum prednisolone plasma concentration, t½, apparent volume of distribution, and AUC. Cimetidine reduced the mean (±SD) ratio of prednisone dose to the plasma prednisolone AUC (16.6 ± 2.9 L/hr) below that ratio after ranitidine (19.2 ± 4.2 L/hr) and placebo (19.3 ± 2.8 L/hr), and resulted in the lowest fractional excretion of prednisolone in the urine (5.2% ± 2.2%, 9.8% ± 4.5%, and 12.4% ± 4.9%, respectively). The minor alterations in prednisolone kinetics during concomitant cimetidine dosing are not likely to induce clinically significant alterations in steroid effect. Clinical Pharmacology and Therapeutics (1985) 37, 534–538; doi: 10.1038/clpt.1985.84