A comparison of the central nervous system effects of caffeine and theophylline in elderly subjects

Br J Clin Pharmacol. 1991 Sep;32(3):341-5. doi: 10.1111/j.1365-2125.1991.tb03909.x.


1. The effects of oral administration of 250 mg caffeine or theophylline and placebo on subjective ratings and psychological test performance were studied in a double-blind crossover experiment in 20 healthy elderly subjects. 2. Performance on the continuous attention task showed a significant improvement compared with placebo with both active treatments. Performance with caffeine was significantly better than with theophylline. Mean error index scores (normalised AUCs) were: placebo--0.130; caffeine--0.083; theophylline--0.093. No other objective measure shows significant treatment effects. 3. Subjective ratings showed that subjects felt significantly more alert on caffeine than on either theophylline or placebo. Subjects also rated themselves as more energetic and interested on caffeine than on placebo. 4. Plasma concentrations of caffeine were lower than those of theophylline (mean 5.76 and 8.72 mg l-1 respectively at 2 h post-drug. 5. These results suggest that caffeine is a more potent CNS stimulant than theophylline.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Caffeine / blood
  • Caffeine / pharmacology*
  • Central Nervous System / drug effects*
  • Double-Blind Method
  • Humans
  • Middle Aged
  • Neuropsychological Tests
  • Psychomotor Performance / drug effects
  • Reference Values
  • Theophylline / blood
  • Theophylline / pharmacology*


  • Caffeine
  • Theophylline