Acute and long-term effectiveness of tulobuterol inhaler, a newβ 2-agonist, in the treatment of asthma

Abstract

Two separate studies were conducted to evaluate the efficacy and safety of tulobuterol and the development of tachyphylaxis, if any, after prolonged use. The first, a double blind, crossover study, compared the efficacy and safety of tulobuterol aerosol 400 micrograms tid and salbutamol aerosol 200 micrograms tid in 38 patients with reversible obstructive airways disease. Each study period lasted 4 weeks, separated by a one week washout period. Evaluation of efficacy was performed on day 1 by monitoring spirometric values up to 6 hours postdosing. Additionally, changes in baseline pulmonary function were evaluated by measuring FEV1, FVC and PEFR at each weekly visit. Twenty-nine patients were evaluable. Tulobuterol was shown to be as effective as salbutamol in onset, peak, and duration of response. Mean increases in FEV1 after tulobuterol ranged from 22% at 5 minutes postdose to 30% at 1 hour postdose; a clinically significant mean increase of 24% was recorded after 3 hours. In comparison, mean increases for salbutamol were 24% at 5 minutes postdose and 31% at 1 hour postdose; after 3 hours the mean increase was 21%. Statistically significantly greater increases in mean baseline FEV1 were recorded in favor of tulobuterol. Following 2 weeks of each treatment, tulobuterol showed a mean increase of 14%, compared to a mean postsalbutamol increase of 12%. After 4 weeks, differences were again statistically significant, with tulobuterol showing a mean increase in baseline FEV1 of 17% compared to 3% for salbutamol. Tulobuterol treatment was associated with smaller changes in blood pressure and pulse rate than salbutamol.(ABSTRACT TRUNCATED AT 250 WORDS)