Recent caffeine ingestion reduces adenosine efficacy in the treatment of paroxysmal supraventricular tachycardia

Miguel S. Cabalag, David Mc Donald Taylor, Jonathan C. Knott, Paul Buntine, De Villiers Smit, Alastair Meyer

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Objectives: Caffeine, an adenosine receptor blocker, should theoretically reduce adenosine efficacy in the treatment of paroxysmal supraventricular tachycardia (SVT). We aimed to determine the effect of recent caffeine ingestion on the likelihood of reversion of SVT with adenosine. Methods: This was a multicenter, case-control study of adult patients with SVT treated with adenosine between September 2007 and July 2008. The primary endpoint was reversion to sinus rhythm (SR) after a 6-mg adenosine bolus, as a function of recent (within 2, 4, 6, and 8 hours) caffeine ingestion. Caffeine ingestion data were collected using a self-administered questionnaire. Results: Of 68 patients enrolled, 52 (76.5%, 95% confidence interval [CI] = 64.4% to 85.6%) reverted after a 6-mg adenosine bolus. There were no significant differences in age, sex, or daily caffeine ingestion between patients who did and did not revert (p > 0.05). However, as a group, patients who did not revert had recently ingested significantly more caffeine (p < 0.05). If caffeine had been ingested less than 2 or 4 hours before the adenosine bolus, the odds of reversion to SR were significantly reduced (odds ratio [OR] = 0.18, 95% CI = 0.04 to 0.93; and OR = 0.14, 95% CI = 0.04 to 0.49, respectively). If caffeine had been ingested less than 6 or 8 hours before the adenosine, the odds of reversion were not reduced (OR = 0.31, 95% CI = 0.09 to 1.02; and OR = 0.31, 95% CI = 0.09 to 1.08, respectively). Conclusions: Ingestion of caffeine less than 4 hours before a 6-mg adenosine bolus significantly reduces its effectiveness in the treatment of SVT. An increased initial adenosine dose may be indicated for these patients.

Original languageEnglish
Pages (from-to)44-49
Number of pages6
JournalAcademic Emergency Medicine
Issue number1
Publication statusPublished - Jan 2010
Externally publishedYes


  • Adenosine
  • Caffeine
  • Emergency department
  • Supraventricular tachycardia

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