Caveat: All recommendations are data-based, but many factors affect successful conversion of paroxysmal supraventricular tachycardia (PSVT) including proper line placement and administration technique.
Caffeine is an adenosine blocker and can interfere with the successful reversion of PSVT. In fact, ingestion of caffeine less than 4 hours before a 6-mg adenosine bolus significantly reduced its effectiveness in the treatment of PSVT. An increased initial adenosine dose may be indicated for these patients.
Remember that theophylline may require higher dosing as well, because it is similar to caffeine (another methylxanthine), but is not prescribed much in the U.S. anymore.
Recommended dosing strategy :
- 1st dose: 12 mg (instead of 6)
- 2nd/3rd doses: 18 mg (instead of 12)
Every so often a patient arrives in PSVT with their only IV access being through a hemodialysis port. The initial adenosine dose should be reduced if administered through a central line. Remember a central line delivers the adenosine right where you need it. This recommendation is supported by the 2010 ACLS guidelines. Cases of prolonged bradycardia and severe side effects have been reported after full-dose adenosine through a central line.
Also consider lower doses in patients concomitantly taking carbamazepine or dipyridamole or in those with a transplanted heart.
Recommended dosing strategy [2, 3, 4]:
- 1st dose: 3 mg (instead of 6)
- 2nd/3rd doses: 6 mg (instead of 12)
- Cabalag MS, et al. Recent caffeine ingestion reduces adenosine efficacy in the treatment of paroxysmal supraventricular tachycardia. Acad Emerg Med 2009;17(1):44-9. [PMID 20003123]
- Chang M, et al. Adenosine dose should be less when administered through a central line. J Emerg Med 2002;22(2):195-8. [PMID 11858927]
- Neumar RW, et al. Part 8: Adult Advanced Cardiovascular Life Support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010;122:S729-S767. [PMID 20956256]
- McIntosh-Yellin NL, et al. Safety and efficacy of central intravenous bolus administration for termination of supraventricular tachycardia. J Am Coll Cardiol 1993;22:741-5. [PMID 8354807]