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Effectiveness of prednisolone during phenytoin therapy
Author(s) -
Petereit Lillie B.,
Meikle A. Wayne
Publication year - 1977
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 - 10.1002/cpt1977226912
Subject(s) - prednisolone , phenytoin , medicine , pharmacology , intensive care medicine , anesthesia , epilepsy , psychiatry
The effects of diphenylhydantoin (DPH) on the clearance of prednisolone from plasma, its bioavailability, and its biologic effectiveness were studied in 5 persons before and after daily DPH therapy for more than 3 wk. DPH decreased the mean half‐time of disappearance of prednisolone from plasma by 45% and increased its metabolic clearance rate by an average of 77%. The gastrointestinal absorption of prednisolone and its first‐pass clearance through splanchnic tissues were not significantly altered by DPH. The mean oral midnight dose of prednisolone required to suppress the 8 A.M. plasma level of cortisol to 5 p,g/dl was doubled following treatment of DPH. The increment in dose of prednisolone varied from 58% to 260% in the five individuals.