Document Detail


Caffeine and paraxanthine pharmacokinetics in the rabbit: concentration and product inhibition effects.
MedLine Citation:
PMID:  3612497     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The disposition of caffeine (C) and its major metabolite paraxanthine (P) have been determined following i.v. bolus dosing both separately and concomitantly to New Zealand White rabbits. Caffeine clearances of 1.52-6.71 ml/min/kg were observed and were suggestive of polymorphism with rapid (type I) and slow (type II) metabolizing subpopulations represented. Type II metabolizers exhibited dose-independent pharmacokinetics for C, while the clearances of type I animals were dose-dependent (lower clearances at higher doses). The P clearances were not dose-dependent. In type I rabbits coadministration of P inhibited C metabolism by as much as 71%. Results were consistent with the hypothesis that at least two forms of cytochrome "P-450" mediate the metabolism of C in the rabbit.
Authors:
S H Dorrbecker; R A Ferraina; B R Dorrbecker; P A Kramer
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of pharmacokinetics and biopharmaceutics     Volume:  15     ISSN:  0090-466X     ISO Abbreviation:  J Pharmacokinet Biopharm     Publication Date:  1987 Apr 
Date Detail:
Created Date:  1987-08-28     Completed Date:  1987-08-28     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0357115     Medline TA:  J Pharmacokinet Biopharm     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  117-32     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Caffeine / metabolism*
Female
Half-Life
Kinetics
Protein Binding
Rabbits
Theophylline / metabolism*,  pharmacology
Ultrafiltration
Grant Support
ID/Acronym/Agency:
HD 16900/HD/NICHD NIH HHS
Chemical
Reg. No./Substance:
58-08-2/Caffeine; 58-55-9/Theophylline; 611-59-6/1,7-dimethylxanthine

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