Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1996-9-30
pubmed:abstractText
A prospective cohort study was conducted to examine the effects of double-strength grapefruit juice on the pharmacokinetics and electrocardiographic repolarization pharmacodynamics of terfenadine in poor metabolizers of terfenadine. Six healthy volunteers who were previously found to be poor metabolizers of terfenadine were studied, with each participant serving as his or her own control. In phase I of the study, terfenadine was given to participants at recommended dosages until steady state was achieved (60 mg twice daily for 7 days). In phase II, participants began receiving concomitant twice-daily, double-strength servings of grapefruit juice for 7 days. Serial pharmacokinetic and pharmacodynamic determinations were made after each phase of the study. The main outcome measures were serum concentrations of terfenadine and terfenadine acid metabolite, and corrected QT intervals as determined by 12-lead electrocardiogram. Significant changes occurred in time to maximum concentration (t(max)) and area under the concentration-time curve (AUC) of terfenadine and terfenadine acid metabolite after addition of grapefruit juice. All participants had detectable concentrations of unmetabolized terfenadine at the end of Phase I, which were quantified in three of the six participants. Further, all participants had increased and quantifiable levels of unmetabolized terfenadine after addition of grapefruit juice that were associated with prolongation of the QT interval relative to the baseline control period without terfenadine. Grapefruit juice did not alter the elimination half-life (t1/2) of terfenadine acid metabolite. Because of the intraindividual variability in the pharmacokinetics of terfenadine, further study is needed to confirm these results.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0091-2700
pubmed:author
pubmed:issnType
Print
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
345-51
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Grapefruit juice alters the systemic bioavailability and cardiac repolarization of terfenadine in poor metabolizers of terfenadine.
pubmed:affiliation
Division of Clinical Pharmacology of the Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.