The effect of vitamin C on the pharmacokinetics of caffeine in elderly men

Am J Clin Nutr. 1982 Mar;35(3):487-94. doi: 10.1093/ajcn/35.3.487.


The influence of vitamin C on the pharmacokinetics of caffeine was investigated in 10 elderly males, age 66 to 86 yr. Caffeine was administered intravenously on three different occasions over a 7-wk period: before vitamin C restriction, after approximately 4 wk of vitamin C restriction (15 mg dietary intake per day), and after 2 wk of vitamin C supplementation (500 mg orally, twice daily). Blood and urine samples were collected over a 48-h period after each caffeine administration. The plasma half-life, rate constant of elimination, apparent volume of distribution, total body clearance, renal clearance, and metabolic clearance of caffeine were determined. Simultaneous plasma, whole blood and leukocyte vitamin C concentrations were obtained. All of the average vitamin C concentrations monitored (plasma, whole blood, and leukocyte) changed significantly during the study, corresponding to the alterations in dietary vitamin C intake. Conversely, none of the caffeine pharmacokinetic parameters evaluated changed significantly during the study. The average metabolic clearance was approximately 77 (ml hr-1) kg-1 and the average half-life was approximately 4.6 h for all caffeine administrations. These results indicate that the elimination of caffeine in the elderly is not affected significantly by the concentrations of vitamin C achieved during this study.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged*
  • Ascorbic Acid / administration & dosage
  • Ascorbic Acid / pharmacology*
  • Caffeine / blood
  • Caffeine / metabolism*
  • Dose-Response Relationship, Drug
  • Humans
  • Kinetics
  • Male
  • Time Factors


  • Caffeine
  • Ascorbic Acid