title: Circadian variation in theophylline 'trough' serum concentrations.
mesh_terms: D002940:Circadian Rhythm; D003692:Delayed-Action Preparations; D006801:Humans; D013806:Theophylline / Q000008:administration & dosage / Q000097:blood*
chemical_list: D003692:Delayed-Action Preparations; D013806:Theophylline