title: Theophylline mitigates the bronchoconstrictor effects of sulfur dioxide in subjects with asthma.
abstract: The objective of the study was to investigate the ability of a sustained-release (SR) theophylline tablet (Uniphyl; Purdue Frederick Co., Norwalk, Conn.) to block or mitigate sulfur dioxide (SO2)-induced bronchoconstriction in adult subjects with asthma. Eight subjects participated in a double-blind, crossover study with a 400 mg theophylline tablet or placebo once a day for a week before a 10-minute SO2 challenge. FEV1 and total respiratory resistance (RT) were measured before and after the SO2 challenge and on a different day before and after an air exposure. After exposure to SO2, average values of FEV1 dropped 16% after placebo treatment and 7% after theophylline treatment. The corresponding percentages for RT were a 37% increase after placebo and a 7% increase after theophylline treatment. Analysis of variance demonstrated a significant difference between the SO2-induced decrease in FEV1 and increase in RT after SR theophylline treatment compared with that of placebo treatment. Thus, we conclude that SR theophylline tablets, taken at this concentration for 1 week, mitigate SO2-induced bronchoconstriction.
authors.affiliation: Department of Environmental Health, University of Washington, Seattle 98195.
authors.forename: J Q
authors.initials: JQ
authors.lastname: Koenig
authors.forename: K
authors.initials: K
authors.lastname: Dumler
authors.forename: V
authors.initials: V
authors.lastname: Rebolledo
authors.forename: P V
authors.initials: PV
authors.lastname: Williams
authors.forename: W E
authors.initials: WE
authors.lastname: Pierson
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000188:drug therapy*; D016085:Bronchoconstrictor Agents / Q000494:pharmacology*; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D013458:Sulfur Dioxide / Q000494:pharmacology*; D013806:Theophylline / Q000008:administration & dosage* / Q000627:therapeutic use
chemical_list: D016085:Bronchoconstrictor Agents; D003692:Delayed-Action Preparations; D013458:Sulfur Dioxide; D013806:Theophylline