THEOPHYLLINE ATTENUATES CIRCULATING VITAMIN-B-6 LEVELS IN CHILDREN WITH ASTHMA

This study was undertaken to investigate the effect of theophylline on circulating vitamin B-6 levels in children with asthma. Twenty-six as thmatic children, including 20 patients who were treated with slow-rel ease theophylline and 6 patients not receiving any type of theophyllin e preparation, were enrolled in this study. Steady state serum theophy lline and vitamin B-6 [pyridoxal 5'-phosphate (PLP) and pyridoxal (PL) ] levels were evaluated in these patients. A depression of serum PLP l evels existed in asthmatic children treated with theophylline compared to those not receiving theophylline (5.3 +/- 0.5 vs. 9.0 +/- 1.4 ng/m l, mean +/- SEM; p < 0.05). A significant negative correlation between the serum levels of PLP and theophylline was demonstrated in the subj ects of this study (r(s) = -0.609, p < 0.001). Oral administration of 200 mg of theophylline (Theo-Dur) to 5 children with asthma significan tly depressed serum PLP levels 4 h after the drug intake (p < 0.05), w hereas theophylline did not affect serum PL levels. From these results , we conclude that theophylline induces a depression of circulating PL P levels in asthmatic children.