Protective effect of theophylline on histamine‐induced bronchoconstriction in asthmatic children.

Abstract

1 The bronchial responsiveness of a group of asthmatic children was studied using histamine stimulation after a single dose of theophylline and after placebo. 2 Theophylline, when levels were greater than 10 ,ug ml17 significantly reduced responsiveness but only by just over one doubling concentration of histamine (P < 0.001).