Oral theophylline disposition in cystic fibrosis

Theophylline absorption and disposition of CF patients have not been systematically studied. To evaluate these factors in CF subjects, seven CF patients were fasted overnight and administered a dose of aminophylline liquid equivalent to 4 mg/kg of anhydrous theophylline. Liver function tests (SGOT, GGT, alkaline phosphatase) were normal in all seven patients. maximum serum theophylline concentrations occurred between 30 and 60 minutes post-dose in all subjects and ranged from 4.8 to 8.6 mcg/ml. These values are similar to those reported in non-CF subjects for a single 4 mg/kg oral dose. The mean serum half-life of 3.5 hours with a range of 1.2 to 5.0 hours is similar to that reported in non-CF populations. The authors conclude that theophylline elimination (half-lives) in CF patients with normal liver function is similar to those of normal and asthmatic patients. CF patients with clinical liver disease may have a decreased clearance and should be carefully monitored.