EFFECT OF INHALED RS-7540, A XANTHONE, ON EXERCISE-INDUCED ASTHMA

Abstract

The effect of 71 oxo-7-thiomethoxyxanthone-2-carboxylic acid sodium salt (RS 7540) inhibiting exercise-induced asthma was compared with that of placebo in a double blind crossover study. Single doses of 40 mg were given by inhalation to 12 patients. Of these 10 subsequently received a dose of 20 mg. RS 7540 at both dose levels had a statistically significant effect in giving total or partial protection from exercise-induced bronchospasm, but no dose relationship was apparent.