Pharmacokinetic consultation program in a pediatric asthma clinic

Abstract

The effect of a clinical pharmacokinetic consultation program for theophylline on the outcomes of pediatric patients with asthma was studied. The program was established in 1989 at a pediatric asthma clinic. For each patient visit, a clinical pharmacist recorded demographic, clinical, and medication-related information and counseled the parents. When an adjustment in the theophylline dosage was indicated, the pharmacist calculated the appropriate dosage using population pharmacokinetic values. If the pediatrician requested a measurement of the serum theophylline concentration, the time when the blood sample was drawn relative to the last dose was recorded, an average serum theophylline concentration at steady state and individualized pharmacokinetic values were calculated, and the dosage was adjusted accordingly. Patient data were compared among three stages: (1) the month before and the month of entry into the program, (2) months 5 and 6 after entry, and (3) months 11 and 12 after entry. A total of 44 patients were studied during each of stages 1 and 2, and 29 patients were reviewed during stage 3. There was a significant improvement in wheezing from stage 1 to stage 2 and in exercise tolerance and nocturnal coughing from stage 1 to stage 2 and stage 1 to stage 3. Forced expiratory volume in one second improved significantly from stage 1 to stage 2, and there was a significant reduction in the necessity for hospital visits for the treatment of exacerbations of asthma between stages 1 and 2. The daily weight-adjusted dose of theophylline increased significantly after the program began. Asthmatic children taking theophylline had improvements in outcome variables after pharmacokinetic consultation and medication counseling were initiated.