Article date: June 1984
By: SH Jackson, JK Wiffen, MM Smythe, A Johnston, in Volume 17, Issue 6, pages 777-779
Ten healthy volunteers were each given two separate courses of eight doses of theophylline 200 mg as a slow release preparation at 12 hourly intervals. In the first course (regimen 1) the dose was given at 11.00 h and 23.00 h and in the second (regimen 2) at 05.00 h and 17.00 h. Sixty hours after the start of each course, four consecutive trough serum theophylline concentrations were measured. On regimen 1 the trough concentration of theophylline was 6.2 +/‐ 2.2 mg/l (mean +/‐ s.d.) at 11.00 h compared with 5.4 +/‐ 1.9 mg/l at 23.00 h (P less than 0.01). This circadian variation was abolished during regimen 2 when the mean theophylline concentrations were identical at 5.2 mg/l. The higher trough concentrations after the evening dose on regimen 1 and the loss of circadian variation on regimen 2 may be due to the change in sleep period in relation to the time of dosing.
DOI: 10.1111/j.1365-2125.1984.tb02419.x
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