RIFAMPICIN (RIFAMPIN) AND THEOPHYLLINE
Rifampicin increases the clearance of theophylline by 45%. In one study rifampicin
(with isoniazid) increased theophylline clearance during the initial few days of
tuberculosis treatment, but another study suggested that these antituberculars
decreased theophylline clearance within 4 weeks.
Monitor theophylline levels. An effect has been seen within 36 hours of starting
rifampicin. Expect to need to increase the theophylline dose. The picture is less
clear when isoniazid is also taken. In this situation it would seem prudent to
monitor theophylline levels closely for the first month of treatment.
(with isoniazid) increased theophylline clearance during the initial few days of
tuberculosis treatment, but another study suggested that these antituberculars
decreased theophylline clearance within 4 weeks.
Monitor theophylline levels. An effect has been seen within 36 hours of starting
rifampicin. Expect to need to increase the theophylline dose. The picture is less
clear when isoniazid is also taken. In this situation it would seem prudent to
monitor theophylline levels closely for the first month of treatment.