-transparent.png){kind=logo}
1. The mechanism of the interaction between ciprofloxacin and theophylline was investigated in nine healthy subjects. 2. Subjects were given a single oral dose of theophylline (3.4 mg kg-1), before and after 60 h of ciprofloxacin therapy at a dose of 500 mg twice daily. 3. Ciprofloxacin reduced the oral clearance of theophylline by 19% (-7.73 +/- 6.42 ml kg-1 h-1 (95% confidence limits -12.66, -2.79)). Some subjects (group A, n = 4) showed little decrease in clearance (mean 4.4%; -1.6 +/- 0.7 ml kg-1 h-1 (-2.6, 0.5)), whereas others (group B, n = 5) showed a marked decrease (mean 30%; -12.7 +/- 3.7 ml kg-1 h-1 (-17.2, -8.1)). 4. Comparing groups A and B, the decrease in oral clearance of theophylline in group B could not be ascribed to differences in the AUC of ciprofloxacin. Group A subjects showed only slight inhibition of 1-demethylation (-12.8 +/- 5.5% (-21.5, -4.0)), while group B subjects showed a significantly greater inhibition of 1-demethylation (-49.9 +/- 9.8% (-62.1, -37.7)), 3-demethylation (-44.8 +/- 8.6% (-55.4, -34.1)) and 8-hydroxylation (-27.0 +/- 3.7% (-31.6, -22.4)). 5. The results suggest that inter-individual variability in the inhibition of theophylline metabolism by ciprofloxacin can be attributed to inter-individual differences in the level of CYP1A2 expression and/or in the degree of inhibition of hepatic CYP1A2 and CYP3A4. 6. The interaction between ciprofloxacin and theophylline can be clinically significant.(ABSTRACT TRUNCATED AT 250 WORDS)
K T Batty, and
T M Davis, and
K F Ilett, and
L J Dusci, and
S R Langton
January 1992,
The Annals of pharmacotherapy,
K T Batty, and
T M Davis, and
K F Ilett, and
L J Dusci, and
S R Langton
December 1985,
International journal of clinical pharmacology, therapy, and toxicology,
K T Batty, and
T M Davis, and
K F Ilett, and
L J Dusci, and
S R Langton
July 1996,
Antimicrobial agents and chemotherapy,
K T Batty, and
T M Davis, and
K F Ilett, and
L J Dusci, and
S R Langton
June 1999,
Journal of clinical pharmacology,
K T Batty, and
T M Davis, and
K F Ilett, and
L J Dusci, and
S R Langton
June 1993,
Therapeutic drug monitoring,
K T Batty, and
T M Davis, and
K F Ilett, and
L J Dusci, and
S R Langton
January 1990,
Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas,
K T Batty, and
T M Davis, and
K F Ilett, and
L J Dusci, and
S R Langton
January 1993,
Pharmacotherapy,
K T Batty, and
T M Davis, and
K F Ilett, and
L J Dusci, and
S R Langton
March 1998,
Antimicrobial agents and chemotherapy,
K T Batty, and
T M Davis, and
K F Ilett, and
L J Dusci, and
S R Langton
April 1983,
Journal of pharmacobio-dynamics,
K T Batty, and
T M Davis, and
K F Ilett, and
L J Dusci, and
S R Langton
January 2009,
Pakistan journal of pharmaceutical sciences,
