These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Ranitidine alters antipyrine metabolism in control and phenobarbital-treated mice.
    Author: Espiritu-Quiza MF, Skinner MH, Blaschke TF.
    Journal: Methods Find Exp Clin Pharmacol; 1990 Nov; 12(9):631-6. PubMed ID: 2084458.
    Abstract:
    The effect of ranitidine on both induced (phenobarbital) and uninduced cytochrome P450 enzymes was investigated in mice using the [14C]-labeled antipyrine breath test. Ranitidine administration resulted in a decrease in the fraction of the administered dose of antipyrine exhaled as radiolabeled CO2 (CERAUC0-infinity) indicating inhibition in the demethylase pathway (Kdm), and resulted in induction of enzymes in the non-demethylase pathways (Kndm) as well. No change in antipyrine total elimination rate constant (Kel) was seen after ranitidine administration alone. Concurrent administration of ranitidine and phenobarbital resulted in an increase in the (Kel) but the change was less than that seen after phenobarbital alone. A reduction in CERAUC0-infinity was seen after the combination treatment while phenobarbital alone resulted in an increase in this parameter. Ranitidine, therefore, alters the pattern of antipyrine metabolism by inhibition of demethylase enzymes and induction of non-demethylase enzymes, the former activity being more pronounced in induced forms. Because of the simultaneous occurrence of both effects, no change in antipyrine half-life was noted with uninduced P450 isozymes.
    [Abstract] [Full Text] [Related] [New Search]