title: Theophylline metabolism after cardiac surgery.
abstract: The effect and metabolism of theophylline administration after cardiac surgery has never been reported. Two series of 2-hour intravenous aminophylline administrations (3 mg/kg/h) were conducted in 10 adult patients on the operative day (acute phase) and on the 4th or 5th postoperative day (recovery phase). Both blood and urine samples were collected for 24 hours after dosing. Heart rate increased in both phases, but the cardiac index increased with the decrease of diastolic blood pressure only in the acute phase (p < 0.05). Plasma concentration levels of theophylline tended to be slightly higher in the acute phase, and renal clearance increased in the recovery phase (p < 0.05). The urinary ratio of 3-methylxanthine to theophylline was significantly higher in the acute phase (p < 0.05). This suggests that cytochrome P4501A2 is partially activated rather than depressed and that N-demethylation is promoted more than hydroxylation immediately after surgery.
authors.affiliation: Department of Cardiovascular and Thoracic Surgery, Tsuchiura Kyodo General Hospital, Manabe Shinmachi 11-7 Tsuchiura, Ibaraki 300-0053, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hirooka
authors.forename: M
authors.initials: M
authors.lastname: Shimizu
authors.forename: S
authors.initials: S
authors.lastname: Mineshita
mesh_terms: D000328:Adult; D000628:Aminophylline / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D006348:Cardiac Surgical Procedures; D002318:Cardiovascular Diseases / Q000378:metabolism* / Q000601:surgery; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D011182:Postoperative Care; D013806:Theophylline / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D014665:Vasodilator Agents / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine
chemical_list: D014665:Vasodilator Agents; D000628:Aminophylline; D003577:Cytochrome P-450 Enzyme System; D013806:Theophylline