Time course of change in bronchial reactivity with an inhaled corticosteroid in asthma.

The time course of change in FEV1, bronchial reactivity, and daily measures of asthma control (peak expiratory flow, symptoms, and beta 2-agonist inhaler use) was determined during 6 wk of treatment with inhaled budesonide, 800 micrograms twice a day, and for 2 wk following cessation of treatment in 40 asthmatic subjects in a double-blind, placebo-controlled, parallel group study. Histamine reactivity, expressed as the provocative dose of histamine causing a 20% fall in FEV1 (PD20), was measured at intervals during the 8 wk of the study, with more frequent measurements after the first and last dose of drug to provide a detailed profile of change at the start and end of treatment. The first dose of budesonide caused a small increase in median values of FEV1 (0.2 L) and PD20 (1.0 doubling dose of histamine), which was maximum at 6 h. There was a further increase in FEV1 and PD20 over the 6 wk in the budesonide group relative to placebo, the maximum increases (0.53 L, 3.4 doubling doses of histamine) being recorded 6 h after the last dose on Day 42. Following cessation of treatment, FEV1 and PD20 declined and PD20 returned to placebo values at 1 wk. Median PEF increased by 40 and 30 L/min in the morning and evening, respectively, with budesonide treatment. Symptom scores and beta 2-agonist inhaler use were lower in the budesonide group than the placebo group during treatment but tended to be similar (symptom scores) or higher (beta 2-agonist) in the 2 wk following cessation of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)