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Enoxacin decreases the clearance of theophylline in man.
Author(s) -
Wijnands WJ,
Vree TB,
Herwaarden CL
Publication year - 1985
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/j.1365-2125.1985.tb05115.x
Subject(s) - theophylline , enoxacin , aminophylline , pharmacokinetics , chemistry , bronchodilator , pharmacology , drug interaction , plasma concentration , endocrinology , medicine , antibiotics , ofloxacin , asthma , biochemistry , ciprofloxacin
In patients treated concurrently with theophylline and enoxacin, a new broad‐spectrum antibacterial agent of the quinolone class, unexpectedly high plasma theophylline concentrations were measured. In part I of this study, daily plasma theophylline concentrations were measured in 14 patients. The mean +/‐ s.d. theophylline concentrations increased from 8.5 +/‐ 2.8 micrograms ml‐1 prior to enoxacin to a maximum of 21.7 +/‐ 7.8 micrograms ml‐1 during coadministration. In part II, six of these patients received aminophylline intravenously at a constant infusion rate and under controlled conditions. Plasma theophylline concentrations rose from 8.4 +/‐ 2.4 micrograms ml‐1 prior to enoxacin treatment to 15.0 +/‐ 5.1 micrograms ml‐1 at day 3 of coadministration (P less than 0.005). Plasma protein‐binding and renal clearance of theophylline remained unchanged, whereas total body clearance of theophylline significantly decreased (P less than 0.005). From these observations it is concluded that the rise of plasma theophylline concentrations is caused by a reduced metabolic clearance of theophylline. If concomitant use of both drugs is necessary, monitoring of plasma theophylline concentration and adjustment of the theophylline dose is recommended.