Urinary excretion of 6 beta-hydroxycortisol and the time course measurement of enzyme induction in man.
The effect of enzyme induction by antipyrine, phenobarbitone and rifampicin on the time-course of urinary 6 beta-hydroxycortisol (6 beta-OHC) excretion was investigated in healthy volunteers. The drugs were given chronically for either seven or 14 days. Significant increases in 6 beta-OHC excretion were observed after 4 days administration of antipyrine (1.2 g), 13 days administration of phenobarbitone (100 mg), and only 2 days administration of rifampicin (0.6 or 1.2 g). During 14 days rifampicin administration (1.2 g) 6 beta-OHC excretion, for individual subjects, reached a maximum on Days 11-14 when excretion was significantly greater than on day 7. On stopping rifampicin, in a 7-day study, excretion decreased over the next six days, but still remained significantly elevated compared to the original control values. These studies show that measurement of urinary 6 beta-hydroxycortisol provides a simple non-invasive method with which to monitor the time-course of enzyme induction by drugs in man. However, the method cannot be used to predict clinically important drug interactions until the cytochrome P-450 enzyme responsible for cortisol 6 beta-hydroxylation has been fully characterized.
Ohnhaus
E E
EE
I. Medizinische Klinik der Christian-Albrechts-Universität, Kiel, Federal Republic of Germany.
Breckenridge
A M
AM
Park
B K
BK
D000328:Adult; D000983:Antipyrine / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000652:urine; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008297:Male; D006899:Mixed Function Oxygenases / Q000096:biosynthesis*; D010634:Phenobarbital / Q000008:administration & dosage / Q000494:pharmacology*; D012293:Rifampin / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
C001380:6 beta-hydroxycortisol; D006899:Mixed Function Oxygenases; D000983:Antipyrine; D012293:Rifampin; D006854:Hydrocortisone; D010634:Phenobarbital