Individualizing theophylline dosage: evaluation of a single-point maintenance dose prediction method.
A dosage prediction method to estimate theophylline clearance and dose requirement was evaluated in 22 outpatients with partly reversible obstructive airways disease. The steady state theophylline dose required to achieve a target concentration (Css) was predicted using a single serum theophylline determination 8 h after a single oral test dose. In 17 nonsmoking patients a mean absolute deviation of 8.2% (range 0.0-21.7%) between predicted and observed Css was found, and in 5 smoking patients the mean deviation was 34.0% (range 2.2-53.8%). In 17 healthy smokers the single-point method was found to predict theophylline clearance at a sampling time of 8 h with a prediction error of 11.3 (range 0.8-25.3%) compared to the clearance determination using the area under the curve. In addition, a numerical simulation program to assess the influence of absorption, elimination and sampling time on predictive accuracy showed that the method could be successfully applied to a patient population with elimination rate constants between 0.07 1/h and 0.25 1/h, allowing a mean prediction error of 15%.
D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000188:drug therapy*; D001991:Bronchitis / Q000188:drug therapy*; D003201:Computers; D005260:Female; D006207:Half-Life; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D012907:Smoking; D013806:Theophylline / Q000008:administration & dosage* / Q000378:metabolism / Q000627:therapeutic use; D013997:Time Factors
D013806:Theophylline