[A single dose of theophylline in the evening in chronic obstructive airway disease. Serum concentration and lung function parameter].

In 12 patients with long-standing obstructive respiratory disease, the nocturnal Theophylline plasma levels were investigated after the administration in the evening, of 600 or 800 mg respectively Theophylline given in the form of sustained-release tablets (Uniphyllin), measurements being made on the first, 4th and 5th day of the study. Hourly plasma level measurements were made in the critical period between 4.00 and 8.00 hours. Already on the first study day, Theophylline plasma concentrations were higher than 10 micrograms/ml 5 to 11 hours after medication; on days 4 and 5, corresponding values were achieved after 3 hours. On these days, the course of the curve was virtually identical. Only very small standard deviations were found. Seven hours after medication, the plasma levels of Theophylline were at a peak. On average, this was 14.4 micrograms/ml on day 1, 18.1 micrograms/ml on day 4, and 17.7 micrograms/ml on day 5. Prior to the next dose of Theophylline at 21.00 hours, Theophylline plasma levels of 6.6 and 6.4 micrograms/ml were measured on days 4 and 5, respectively. These figures were thus appreciably above 5 micrograms/ml even after 24 hours. Between 4.00 and 8.00 hours, the Theophylline plasma levels were particularly high, so that in this biorhythmically critical period, the therapeutic effect of Theophylline following an evening single dose of Uniphyllin, is optimally developed.