Minocycline Theophylline

Serum theophylline levels increased in two patients who were also given minocycline or tetracycline. Some controlled studies have shown both increases and decreases in theophylline clearance with doxycycline and tetracycline, with no significant changes overall. 

The serum theophylline levels of a 70-year-old woman with normal liver function increased from 9.8 to 15.5 mg/L after she was given minocycline 100 mg twice daily by infusion for 6 days. Her serum theophylline level was 10.9 mg/L 14 days after the minocycline was stopped. ... 

Information seems to be limited. There are two isolated eases of increased theophylline levels with minocycline and tetracycline, but controlled studies have not shown any significant changes in overall theophylline pharmacokinetics. It has been suggested that a clinically important interaction may possibly only occur in a few patients. Further study is needed. There seems to be no evidence of adverse interactions with any of the other tetracyclines. However, note that acute infections per se can alter theophylline pharmacokinetics. 

Kawai M, Honda A, Yoshida H, Goto M, Shimokata T. Possible theophylline-minocycline interaction. Ann Pharmacother (1992) 26, 1300-1. 

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