Premium
Effect of Multiple Doses of Rifampin on the [ 14 C N ‐methyl] Erythromycin Breath Test in Healthy Male Volunteers
Author(s) -
Gharaibeh Munir N.,
Gillen Lisa P.,
Osborne Barbara,
Schwartz Jules I.,
Waldman Scott A.
Publication year - 1998
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1002/j.1552-4604.1998.tb05785.x
Subject(s) - cyp3a , erythromycin , reproducibility , medicine , pharmacology , discontinuation , oral administration , in vivo , chemistry , antibiotics , cytochrome p450 , biology , chromatography , metabolism , biochemistry , microbiology and biotechnology
The erythromycin breath test (EBT), which measures 14 CO 2 produced from [ 14 C N‐ methyl] erythromycin, is one of the most frequently employed measures to examine drug interactions involving cytochrome P450 3A4 (CYP3A). However, the reproducibility and reliability of this test, and the effects of drugs that alter CYP3A activity, continue to be defined. In this study, the reproducibility of the EBT was evaluated in eight healthy volunteers before and after oral administration of 600 mg of rifampin daily for 8 days. Two sequential EBT determinations performed 5 days apart before rifampin administration were highly reproducible. Rifampin induced CYP3A, reflected in a mean percent (± standard deviation) increase in EBT values of 86 ± 30%. Recovery of enzyme function after discontinuation of rifampin for 17 days was manifested as a return of EBT values to preinduction levels. These results support the utility of EBT as a valid, reproducible, and reliable measure of CYP3A activity in vivo.