Nocturnal asthma: effect of a once per evening dose of sustained release theophylline.

In a double-blind, multiple-dose, cross-over study the therapeutic effects of an S-R theophylline preparation given once each night (mean 11.2 mg/kg/day) were compared to standard treatment with an S-R aminophylline preparation every 12 h (mean 10.3 mg theophylline/kg/day) in 9 patients with nocturnal asthma. On Day 5 of each treatment period, serum theophylline concentrations and PEF were measured every 2 h over a 24 h period. With the twice-daily regimen peak theophylline concentrations were lower at night than during the day (mean 9.4 +/- 0.9 vs 11.3 +/- 1.0 mg/1). With the single administration, serum theophylline concentrations were considerably higher at night (mean C max 16.3 +/- 1.4 mg/1). In spite of the high theophylline peak to trough difference (mean 12.0 +/- 2.1 mg/1) during the once daily regimen, the circadian variations of PEF were significantly reduced. Thus, greater airways' stability can be obtained by appropriate timing of theophylline administration.