[Serum pyridoxal concentration in children during theophylline therapy for bronchial asthma].

This study was designed to investigate the effect of sustained-release theophylline therapy on serum pyridoxal concentration in children with bronchial asthma. Forty-two children with bronchial asthma were divided into two groups according to duration of theophylline administration: The 22 children in group A had been treated with theophylline for less than 4 weeks, whereas the 20 children in group B had been treated for more than 5 weeks. The results obtained from this study were as follows: 1) The serum pyridoxal concentration in group B was significantly lower than that those in group A (p < 0.01). 2) The serum pyridoxal concentration was not significantly correlated with the serum theophylline concentration. These findings suggest that long-term theophylline therapy can depress vitamin B6 status in children with bronchial asthma. Theophylline-induced seizure may be caused by the possible decreased in gamma-aminobutyric acid concentration in the brain as a result of decrease in gamma-aminobutyric acid concentration in the brain as a result of decrease in vitamin B6 status, even if the serum theophylline concentrations are within the therapeutic range.