Impairment of caffeine clearance by chronic use of low-dose oestrogen-containing oral contraceptives

D. R. Abernethy, E. L. Todd

Research output: Contribution to journalArticle

Abstract

The effect of chronic (>3 months) administration of low-dose oestrogen-containing (<50 μg oestrogen) oral contraceptives (OCS) on the pharmacokinetics of caffeine has been examined in a treated females matched with 9 non-smoking, drug-free, healthy control females of similar age, weight and ethnic origin. Each subject received 162 mg caffeine base orally after an overnight fast. OCS subjects had a prolonged elimination half-life of caffeine, (mean 7.88 h vs 5.37 h in the controls). This was the result of marked impairment of the plasma clearance of caffeine (1.05 vs 1.75 ml/min/kg, respectively) with no change in apparent volume of distribution (0.685 in OCS vs 0.750 l/kg in the control group). The absorption parameters determined were peak plasma caffeine concentration (3.99 vs 4.09 μg/ml) and time to peak concentration after drug administration (1.52 vs 0.79), which was moderately prolonged in OCS users. Thus, caffeine clearance, previously reported to be a specific marker of cytochrome P-448 activity in man, is decreased by chronic OCS use. This suggests that OCS may cause significant impairment of this enzyme activity as assessed in vivo. With chronic caffeine consumption, OCS users are predicted to have an increased steady-state plasma caffeine concentration as compared to non-OCS users.

Original languageEnglish (US)
Pages (from-to)425-428
Number of pages4
JournalEuropean journal of clinical pharmacology
Volume28
Issue number4
DOIs
StatePublished - Jul 1 1985

    Fingerprint

Keywords

  • caffeine
  • elimination half-life
  • oral contraceptives
  • pharmacokinetics

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)

Cite this