The bronchodilator effect of caffeine in adult asthmatics

Caffeine has been reported to result in bronchodilation in asthmatic children. Our study was designed to assess the effect of caffeine on pulmonary function in adults with asthma. We studied 8 patients: 4 men and 4 women with previously documented airway reactivity. A randomized, double-blind cross-over was used. The patients received either placebo or 5 mg/kg of caffeine in solution orally, and FEV1, FVC, FEF25-75, Vmax25 and blood for caffeine concentrations were taken at several time points for as long as 8 h after the drink.

there was a significant difference between caffeine and placebo for percent change in FEV1 with peak change at 1.5 h. There was also a significant difference for percent change in FEF25-75 with peak occurring at 4 h. Percent change in Vmax25 was significantly different at 3.0 h only. Peak caffeine concentration of 8.7 +/- 1.7 micrograms/ml occurred at 1 h. The data indicate that caffeine at a dose of 5 mg/kg can produce significant percentage improvement in FEV1, FEF25-75, and Vmax25 in adult asthmatics.