Steady-state evaluation of twice-a-day dosing of a new sustained-release theophylline preparation for young children.

We studied the absorption properties of a new sustained-release theophylline, Theo-Dur Sprinkle (TS), to see if this formulation when given on a b.i.d. basis results in acceptable steady-state theophylline levels in children with asthma. Twelve patients (ages 5-8 years), after multiple TS dosing, had serum theophylline levels determined over a 10-hr period after a morning TS dose. Fluctuations in serum theophylline concentrations were acceptable with the observed mean percent peak-to-trough fluctuation [(peak-trough/trough) x 100] being 53%. Patients required higher than usually recommended theophylline doses to obtain therapeutic levels, suggesting incomplete absorption of TS; this was documented with one patient using a 100% bioavailable theophylline product as a comparison.