Presence of sulfur dioxide in commonly used bronchodilator solutions.

We detected a significant amount of SO2 released from commercially used bronchodilators, including isoproterenol (Isuprel; Breon Laboratories, Inc., New York, N. Y.), metaproterenol (Alupent; Boehringer Ingelheim, Ridgefield, Conn., or Metaprel; Dorsey Laboratories, Lincoln, Neb.), isoetharine (Bronkosol; Breon Laboratories, Inc., New York, N. Y.), and racemic epinephrine (Micronefrin; Bird Corp., Palm Springs, Calif.). During standard nebulization of these agents, SO2 concentration varied from 0.1 to 6.0 ppm. These levels are known to be bronchoconstrictive in asthmatic patients. We believe clinicians should be aware of this observation when sulfite-containing bronchodilators are used.