A comparative study of various combinations of ipratropium bromide and metaproterenol in allergic asthmatic patients.

The bronchodilator effect of ipratropium bromide (IB) (Atrovent-Sch 1000), 40 micrograms inhaled, and metaproterenol (Met), 1.25 mg in various combinations, was compared in ten allergic asthmatic patients, aged 23 to 63 years. Six combinations were used at random in a double blind study. The following ventilatory functions-FVC, TGV, SGAW, FEV1, FEF 25-75, VEmax, VE50, VE25, were measured at 30 min. intervals for the first two hours and at 60 minute intervals for the additional three hours. Inhalation of IB followed by Met resulted in additive bronchodilator effect that was significantly greater and longer than IB alone (p less than 0.05), Met alone (p less than 0.05), two consecutive inhalations of Met (p less than 0.05), or Met followed by IB (p less than 0.05). The bronchodilating effect of IB and Met after five hours was the same as IB after one hour.