Caffeine can interfere with the successful reversion of paroxysmal supraventricular tachycardia (SVT) by adenosine.
Caffeine is an adenosine receptor blocker.
Ingestion of caffeine less than 4 hours before a 6-mg adenosine bolus significantly reduced its effectiveness in the treatment of SVT. Theophylline is similar but not many patients are prescribed it anymore.
An increased initial adenosine dose may be indicated for these patients. A first dose of 12 mg (instead of 6), followed by 2nd and 3rd doses of 18 mg (instead of 12) may be indicated.
References
Cabalag MS, et al. Recent caffeine ingestion reduces adenosine efficacy in the treatment of paroxysmal supraventricular tachycardia. AcadEmerg Med 2009;17(1):44-9.
