The interaction of erythromycin with theophylline

Research output: Contribution to journalArticle


We have studied the interaction of erythromycin with theophylline. We gave ten healthy volunteers theophylline as an intravenous loading dose (5 mg X kg-1) over 1 h, followed by a maintenance infusion (0.5 mg X kg-1 X h-1) for 5 h. A second infusion of theophylline was given after 9 days of treatment with 1 g erythromycin base daily, and the concentrations of theophylline were determined during the infusion periods. The concentrations of erythromycin were measured for 8 h, after one week of treatment, and also after the last erythromycin dose, simultaneously with the second theophylline infusion. Concentrations within the therapeutic range were obtained with both drugs. A significant increase in both AUC and mean plasma concentrations of theophylline was seen during erythromycin treatment. The plasma clearance of theophylline was reduced in 9 of the 10 subjects. Renal clearance increased correspondingly, but the change was not statistically significant. Serum concentrations of erythromycin fell significantly, by more than 30%, with concurrent theophylline medication. We conclude that an interaction between theophylline and erythromycin, affecting both drugs, can be shown with concentrations of the drugs within the therapeutic range.


  • Otto Paulsen
  • P Höglund
  • L G Nilsson
  • H I Bengtsson
External organisations
  • Skåne University Hospital
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Pharmacology and Toxicology


  • Adult, Drug Interactions, Erythromycin, Female, Humans, Infusions, Intravenous, Injections, Intravenous, Kidney, Kinetics, Male, Metabolic Clearance Rate, Middle Aged, Theophylline, Journal Article
Original languageEnglish
Pages (from-to)493-8
Number of pages6
JournalEuropean Journal of Clinical Pharmacology
Issue number5
Publication statusPublished - 1987
Publication categoryResearch