Cimetidine-theophylline complex formation

Methods Find Exp Clin Pharmacol. 1983;5(1):55-8.


Cimetidine forms a complex with theophylline in vitro in both pH 7.4 buffer and human plasma. The increase in the amount of theophylline in solution is about 20% in the buffer system and about 36% in plasma. It is hypothesized that this complex formation may contribute to and be part of the mechanism of the clinically observed decreased theophylline clearance in man in presence of cimetidine.

MeSH terms

  • Chemical Phenomena
  • Chemistry
  • Cimetidine / blood*
  • Drug Interactions
  • Guanidines / blood*
  • Humans
  • Theophylline / blood*


  • Guanidines
  • Cimetidine
  • Theophylline