Dose-related effect of beclomethasone dipropionate on airway responsiveness in asthma.

The effects of twice daily inhaled beclomethasone dipropionate (BDP) at two dose levels (500 and 1,000 micrograms daily) on the airway responsiveness to inhaled histamine was evaluated by a randomized, single-blind, cross-over study in 10 patients with stable asthma. The 12-week study began with a 3-week run-in period of baseline treatment, which was continued unchanged throughout the study, and the two treatment periods were separated by a 3-week placebo period. Patients attended the laboratory every 3 weeks for spirometry and histamine inhalation tests to determine the provocative concentration of histamine causing a 20% fall in forced expiratory volume in 1 s (PC20 of FEV1). There was a similar significant improvement (p less than 0.05) in mean FEV1 after both treatments. There was no significant change in PC20 after treatment with 500 micrograms daily, the geometric mean being 0.587 mg/ml after the placebo period and 0.860 mg/ml after BDP treatment. There was a significant improvement in PC20 (1.930 mg/ml) after treatment with 1,000 micrograms BDP daily in comparison with the placebo and treatment periods with 500 micrograms BDP daily (p less than 0.001). These results suggest that higher doses than usual of inhaled BDP must be used to control airway responsiveness in asthmatics.

Effect of ketotifen on the bronchodilation induced by salbutamol.

Twelve subjects with stable asthma each inhaled two puffs (200 micrograms) of salbutamol on 2 separate days 3 h after double-blind oral administration of ketotifen (two 1-mg capsules) or identical placebo. FEV1 was recorded before and at intervals for 4 h after inhalation of salbutamol. Overall, the FEV1 was significantly greater during the 4-hour period after premedication with ketotifen (p less than 0.02) and the difference between the effect of placebo and ketotifen was statistically significant at 120, 180 and 240 min after salbutamol (p less than 0.05).

Oral sustained-release aminophylline and bronchodilator response to inhaled fenoterol in patients with chronic airflow obstruction.

The bronchodilator response to inhaled fenoterol (400 micrograms) was examined in the morning and in the afternoon before and during oral sustained-release aminophylline treatment in eight patients with chronic reversible airway obstruction. Bronchodilatation was evaluated by measuring serial peak expiratory flow rates (PEFR) for eight hours after inhaled fenoterol and calculating the area under the time-response curves and the percentage increment from the baseline values. The patients showed an enhancement of the bronchodilatation achieved with fenoterol in the morning during aminophylline treatment. In the afternoon, instead, the effect of the fenoterol was not improved by oral aminophylline. This different effect of oral aminophylline might depend on the variable degree of potential reversibility present or diurnal variation in the bronchial response.