Specific antagonism of adenosine-induced bronchoconstriction in asthma by oral theophylline

Br J Clin Pharmacol. 1985 May;19(5):685-92. doi: 10.1111/j.1365-2125.1985.tb02696.x.


The airway response to increasing concentrations of inhaled-adenosine and histamine after oral theophylline or matched placebo was studied in nine asthmatic subjects. Changes in airway calibre were followed as sGaw and FEV1 and concentration-response curves constructed. Inhaled adenosine caused concentration-related bronchoconstriction and was four-five times less potent than inhaled histamine. Theophylline, which achieved a mean plasma level of 15.9 and 16.6 micrograms/ml on the histamine and adenosine study days respectively, caused significant increases in FEV1 (17%) and sGaw (41-53%) whereas placebo had no effect. Theophylline also protected the airways against histamine-and adenosine-induced bronchoconstriction. However theophylline had a greater protective effect against adenosine (concentration-ratio 17.4 for FEV1 and 12.8 for sGaw) than against histamine (concentration ratio 5.6 for FEV1 and 5.4 for sGaw (P less than 0.05]. At therapeutic concentrations theophylline is a specific antagonist of the airway effects of adenosine in addition to being a bronchodilator and a functional antagonist.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine / antagonists & inhibitors*
  • Adult
  • Airway Resistance / drug effects
  • Asthma / physiopathology*
  • Bronchi / drug effects*
  • Bronchodilator Agents / pharmacology
  • Female
  • Forced Expiratory Volume
  • Histamine / pharmacology
  • Humans
  • Male
  • Random Allocation
  • Theophylline / blood
  • Theophylline / pharmacology*


  • Bronchodilator Agents
  • Histamine
  • Theophylline
  • Adenosine