The effect of the 4-quinolone enoxacin on plasma theophylline concentrations.
In patients treated concomitantly with theophylline and enoxacin, a broad spectrum antibacterial agent for oral administration, unexpectedly high plasma theophylline concentrations were observed. In six patients receiving intravenous aminophylline under controlled conditions, enoxacin was started in a daily dose of 800 or 1200 mg. Plasma theophylline concentrations increased from 8.4 +/- 2.4 mg/l to 15.0 +/- 5.1 mg/l at day 3 of co-administration. Total body clearance of theophylline decreased significantly, whereas renal clearance and protein binding did not change. When enoxacin, 800 mg daily, was administered to seven patients with a stable chronic obstructive pulmonary disease, who were on long-term theophylline treatment a significant increase in plasma theophylline concentrations occurred as well: elimination half-life was prolonged. 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, to avoid toxicity.
Wijnands
W J
WJ
Vree
T B
TB
Van Herwaarden
C L
CL
D000328:Adult; D000368:Aged; D000890:Anti-Infective Agents / Q000009:adverse effects* / Q000627:therapeutic use; D004347:Drug Interactions; D015365:Enoxacin; D005260:Female; D006207:Half-Life; D006801:Humans; D008297:Male; D008875:Middle Aged; D009287:Naphthyridines / Q000009:adverse effects* / Q000627:therapeutic use; D012141:Respiratory Tract Infections / Q000188:drug therapy; D013806:Theophylline / Q000097:blood*; D013997:Time Factors
D000890:Anti-Infective Agents; D009287:Naphthyridines; D015365:Enoxacin; D013806:Theophylline