Population Pharmacodynamic Model of Bronchodilator Response to Inhaled Albuterol in Children and Adults With Asthma

作者：Blake Kathryn^*; Madabushi Rajanikanth; Derendorf Hartmut; Lima John

来源：Chest, 2008, 134(5): 981-989.

DOI：10.1378/chest.07-2991

• African American
• albuterl
• asthma
• bronchodilator
• cumulative dose of albuterol required to bring about 50% of maximum effect of albuterol
• ethnicity of albuterol
• metered-dose inhaler
• nebulizer
• pharmacodynamic model
• white race

Background: Because interpatient variability in bronchodilation from inhaled albuterol is large and clinically important, we characterized the albuterol dose/response relationship by pharmacodynamic modeling and quantified variability.
Methods: Eiglity-one patients with asthma (24% African American [AA]; 8 to 65 years old; baseline FEV1, 40 to 80% of predicted) received 180 mu g of albuterol from a metered-dose inhaler (MDI), and then 90 jig every 15 min until maximum improvement or 540 jig was administered; all then received 2.5 mg of nebulized albuterol. FEV1 was measured 15 min after each dose. The population cumulative dose/response data were fitted with a sigmoid maximum effect of albuterol (Emax) [maximum percentage of predicted FEV1 effect] model by nonlinear mixed-effects modeling. The influence of covariates OD maximum percentage of predicted FEV1 reached after albuterol administration (Rmax) and cumulative dose of albuterol required to bring about 50% of maximum effect of albuterol (ED50) and differences between AA and white patients were explored.
Results: ED50 was 141 mu g, and Emax was 24.0%. Coefficients of variation for ED50 and Emax were 40% and 56%, respectively. Ethnicity was a statistically significant covariate (p < 0.05). AA and white patients reached 82.4% and 91.9% of predicted FEV, respectively (p = 0.0004); and absolute improvement in percentage of predicted FEV, was 16.6% in AA patients vs 26.7% in white patients (p < 0.0003). There were no baseline characteristic differences between AA and white patients. Nebulized albuterol increased FEV1 >= 200 mL in 21% of participants. Heart rate and BP were unchanged from baseline after maximal albuterol doses.
Conclusions: Our model predicts that 180 jig of albuterol by MDI produces a 14.4% increase in percentage of predicted FEV1 over baseline (11.7% in AA patients, and 17.5% in white patients). Emax varies widely between asthmatic patients. AA patients are less responsive to maximal doses of inhaled albuterol than white patients. (CHEST 2008; 134:981-989)

• 出版日期2008-11