Pharmacokinetics of theophylline metabolites in 8 Chinese patients.
OBJECTIVE
To study theophylline metabolites pharmacokinetics in patients after a therapeutic dose.


METHODS
Eight adult patients with mild bronchial asthma and normal liver function were infused aminophylline intravenously (6.6 mumol.kg-1). The plasma concentrations of theophylline and its 4 metabolites: 1,3-dimethyluric acid (DMUA), 3-methylxanthine (3-MX), 1-methyluric acid (MUA), and the intermediate 1-methylxanthine (1-MX) were monitored by HPLC throughout 24 h.


RESULTS
The plasma concentration of DMUA was the highest one among the 4 metabolites. 3-MX showed the slowest elimination rate. The plasma concentration of 1-MX throughout a 24-h period showed that there was a picking up of 1-MX (from 0.04 mumol.L-1 to 1.05 mumol.L-1) in the next morning.


CONCLUSIONS
The formation of DMUA was the main metabolites. During night there was an accumulation of 1-MX.
Cao
W
W
Department of Clinical Pharmacology, Jinling Hospital, Nanjing, China.
Zhuo
H T
HT
Chen
G
G
Ling
S S
SS
D000328:Adult; D000628:Aminophylline / Q000378:metabolism / Q000493:pharmacokinetics; D001249:Asthma / Q000378:metabolism*; D001993:Bronchodilator Agents / Q000378:metabolism / Q000493:pharmacokinetics; D002940:Circadian Rhythm; D006801:Humans; D008875:Middle Aged; D013806:Theophylline / Q000493:pharmacokinetics*; D014527:Uric Acid / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D014970:Xanthines / Q000493:pharmacokinetics*
D001993:Bronchodilator Agents; D014970:Xanthines; D014527:Uric Acid; D000628:Aminophylline; C030530:1-methyluric acid; C053085:1-methylxanthine; D013806:Theophylline; C031274:1,3-dimethyluric acid; C029703:3-methylxanthine