Pharmacokinetics of theophylline and enprofylline in patients requiring a high or low dose of theophylline.
In patients requiring a high or low dose of theophylline the pharmacokinetics of theophylline and enprofylline were studied. The low-dose group took an average daily dose of 8.91 mg/kg body wt. and the high-dose group 24.75 mg/kg body wt. The average half-life of theophylline in the former was 7.11 h and in the latter 4.72 h. The average clearances (CL) of theophylline were 2.83 and 4.58 l/h, respectively. The daily oral intake of theophylline was negatively correlated with the theophylline t1/2 (r = -0.63). While the t1/2 of enprofylline was similar in the two groups, CL and volume of distribution (Vc) were slightly (about 30%) but significantly higher in patients requiring a high dose of theophylline. CL of enprofylline did not correlate with CL of theophylline, nor was the Vc of the two drugs correlated. Interindividual variability in t1/2 and CL was considerably lower for enprofylline than for theophylline.
D001993:Bronchodilator Agents / Q000378:metabolism*; D005260:Female; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D008297:Male; D013806:Theophylline / Q000008:administration & dosage / Q000378:metabolism*; D014970:Xanthines / Q000378:metabolism*
D001993:Bronchodilator Agents; D014970:Xanthines; D013806:Theophylline; C034347:enprofylline