Verapamil vs adenosine for SVT

Most people reach for the adenosine once vagotonic manouevres have failed in SVT, but some patients find the side effects – albeit short-lived – pretty unpleasant. For this reason I’ve heard Jerry Hoffman espouse the relative benefits of verapamil in patients without contra-indications. A recent meta-analysis suggests both verapamil and adenosine have about a 90% success rate. The study did not look at recurrence rates of SVT, which one might expect to be higher with the shorter-acting adenosine.
The authors conclude:
The choice between the agents should be made on a case by case basis with awareness of the respective adverse effect profiles, and should involve informed discussion with the patient where appropriate.

OBJECTIVE: Verapamil and adenosine are the most common agents used to treat paroxysmal supraventricular tachycardia (PSVT). We performed a systematic review and meta-analysis to determine the relative effectiveness of these drugs and to examine their respective adverse effect profiles.
METHODS: We searched MEDLINE, EMBASE, CINAHL, the Cochrane database, and international clinical trial registers for randomized controlled trials comparing adenosine (or adenosine compounds) with verapamil for the treatment of PSVT in stable adult patients. The primary outcome was rate of reversion to sinus rhythm. Secondary outcome was occurrence of pooled adverse events. Odds ratios and 95% confidence intervals (CIs) were calculated using a random effects model (RevMan v5).
RESULTS: Eight trials were appropriate and had the available data. The reversion rate for adenosine was 90.8% (95% CI: 87.3-93.4%) compared with 89.9% for verapamil (95% CI: 86.0-92.9%). The pooled odds ratio for successful reversion was 1.27 (95% CI: 0.63-2.57) favouring adenosine. This was not statistically significant. There was a higher rate of minor adverse effects described with adenosine (16.7-76%) compared with verapamil (0-9.9%). The rate of hypotension was lower with adenosine [0.6% (95% CI: 0.1-2.4%)] compared with verapamil [3.7% (95% CI: 1.9-6.9%)].
CONCLUSION: Adenosine and verapamil have similar efficacy in treating PSVT. Adenosine has a higher rate of minor adverse effects, and of overall adverse effects, whereas verapamil has a higher rate of causing hypotension. A decision between the two agents should be made on a case-by-case basis and ideally involve informed discussion with the patient where appropriate.

The relative efficacy of adenosine versus verapamil for the treatment of stable paroxysmal supraventricular tachycardia in adults: a meta-analysis
Eur J Emerg Med. 2011 Jun;18(3):148-52

4 thoughts on “Verapamil vs adenosine for SVT”

  1. Thanks Cliff, an interesting review. The main reason to use verapamil seems to be that “many patients find the transient effects of adenosine very distressing, and the
    potential for persistent psychological effects cannot be discounted”. This is where we show our stripes as EM physicians – explaining, reassuring and leading the patient through the experience so it isn’t a terrifying one. Nice to have good evidence of verapamil as an alternative though.

  2. I don’t have access to the paper, however, I was wondering what their definition was of “minor adverse effects”. Verapamil has been all but eliminated prehospital in my area due to its high rate of side effects (probably due to inappropriate administration rate).
    All of the side effects I’ve witnessed from adenosine have been transient, usually no more than 60 seconds.
    Side effects secondary to calcium channel blockers tend to be a lot longer lived!

  3. Why does no one ever mention pharmacologic anxiolysis with adenosine use?
    I’ve been giving a small dose of midazolam prior to adenosine use for a few years now. Patients love it, especially those who have had a bad prior experience with adenosine.
    I’m yet to hear a convincing argument for not doing this- you wouldn’t reduce a fracture without analgesia/amnesia/anxiolysis: why is adenosine any different?

  4. Would Cardizem be an appropriate option if we are just looking for a CCB? Is there a different action with Verapamil? I like the idea of pre-emptive Midazolam for pts that have voiced bad experiences in the past. Most of all, good point about the importance of talking to our pts, explaining to them what to expect.

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