ArticlePharmaceutical research1995
Effect of norfloxacin on theophylline disposition: a comparison with other fluoroquinolones.
Article in Pharmaceutical research, 1995. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
4 citing papers in PubMed, 10 citations in OpenAlex.
- Development of a physiologically-based pharmacokinetic model of the rat central nervous system.Pharmaceutics · 2014Article
- Norfloxacin blood-brain barrier transport in rats is not affected by probenecid coadministration.Antimicrobial agents and chemotherapy · 2006Article
- Pharmacokinetic-pharmacodynamic modeling of the electroencephalogram effect of norfloxacin in rats.Antimicrobial agents and chemotherapy · 2003Article
- Ignoring pharmacokinetics may lead to isoboles misinterpretation: illustration with the norfloxacin-theophylline convulsant interaction in rats.Pharmaceutical research · 2002Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 1 institution in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The effects of norfloxacin (NOR), at steady-state plasma concentrations of 0-32 mg.l-1, on the plasma clearance of a 6 mg.kg-1 i.v. bolus dose of theophylline (THEO) in the male Sprague-Dawley rat have been studied. The effects were characterised by a Ki value (Ki = 12 microM), which was comparable with Ki values obtained previously under identical conditions for ciprofloxacin, but higher than that obtained for enoxacin. The distributional characteristics, volume of distribution and liver to plasma concentration ratio, were very similar for the three compounds. The only marked pharmacokinetic differences were in hepatic clearance, where there was a rank order NOR > ciprofloxacin > enoxacin, a reverse of the order in the reduction of THEO clearance seen in clinical studies. The advantages of using the steady-state experimental design described here are that equivalent concentrations are utilised to compare related drugs and differences in pharmacokinetics are accounted for, to allow a direct comparison of potency. This information, together with additional pharmacokinetic considerations, suggests that the different effects on THEO clearance seen in the clinic for NOR, ciprofloxacin and enoxacin are not solely due to differences in inhibitory potency, but also involve differences in hepatic clearance and hence systemic availability of the fluoroquinolones.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.