2002 年 28 巻 1 号 p. 63-67
We investigated the appearance of various factors causing fluctuations in the metabolic fate of theophylline (TP) in pneumoconiosis outpatients. Concurrent drug use, congestive heart failure, and smoking were found to be fluctuation factors. There were 4 patient groups, 3 with one of these factors each and a control group with none of the factors. We investigated the correlations between the TP dose and the serum concentration and between age and the serum concentration/dose (C/D) ratio in these 4 groups. The relationships between the dose and serum concentration were as follows : control group : Y=1.377X (p<0.0001), concurrent drug use group : Y=1.408X (p<0.0001), congestive heart failure group : Y=1.695X (p<0.0001), and smoking group : Y=1.025X (p=0.0002). Linearity was obtained for each, and a significant difference (p<0.05) in the regression line was only seen between the congestive heart failure and smoking groups. In addition, compared with the control group, the serum concentration tended to rise when receiving a high dose in the congestive heart failure group. No significant correlation was found between age and the C/D ratio in any of the groups, but the C/D ratio was lower in the smoking group than in any of the 3 other groups (p<0.05).
The above results suggest that when administering TP to pneumoconiosis patients one should pay special attention to fluctuation factors in order to decrease the TP clearance (TPCL) due to congestive heart failure when administering high doses of drugs, in patients with an increased TPCL due to smoking.