Metaproterenol solution in the treatment of asthmatic patients by intermittent positive pressure breathing.

The effects of five different doses of a 5% inhalant solution of metaproterenol on pulmonary function were compared in a placebo-controlled double-blind cross-over study in 40 asthmatic patients who received the drug via intermittent positive pressure breathing (IPPB). The response to metaproterenol in terms of FVC, FEV1, RA, and FEF25-75% was significantly superior to the placebo response. The effect of metaproterenol set in within 5 minutes of adminstration, and clinically significant improvement in pulmonary function was sustained for 6 hours even at the lowest dose level. Global response evaluations reflected a progressive increase in effectiveness with each successive dose increment. Typical sympathomimetic side effects such as nervousness and shakiness slightly increased in frequency with higher doses. At none of the metaproterenol doses were any clinically significant changes observed in the mean blood pressure and pulse rate values.