Does Atracurium Cause Tachycardia?
No, atracurium does not cause tachycardia—in fact, it has no clinically significant effects on heart rate at recommended doses and may be associated with bradycardia more commonly than other muscle relaxants. 1
Cardiovascular Profile of Atracurium
Atracurium is cardiovascularly neutral with respect to heart rate. The FDA label explicitly states that "atracurium has no clinically significant effects on heart rate in the recommended dosage range" and "will not counteract the bradycardia produced by many anesthetic agents or vagal stimulation." 1 This is a critical distinguishing feature from other neuromuscular blocking agents.
Key Mechanism
Unlike pancuronium (which causes tachycardia through vagolytic actions) or rocuronium (which can cause tachycardia in up to 30% of patients), atracurium lacks vagal blocking activity. 2 The absence of vagolytic effects means:
- Bradycardia during anesthesia may actually be MORE common with atracurium than with other muscle relaxants 1
- It will not counteract vagal stimulation from surgical manipulation or anesthetic agents
- Episodes of bradycardia reported with atracurium are attributed to the absence of antagonism of vagal stimuli, not to direct drug effects 3
Clinical Evidence
Research directly comparing atracurium to other agents confirms minimal heart rate changes:
- Atracurium produced a mean change of only -1.6 ± 1.3 beats/min (essentially no change), while tubocurarine increased heart rate by +9.9 ± 1.9 beats/min 4
- Electrophysiological studies in transplanted hearts showed atracurium induced no changes in automaticity, conduction, or refractoriness in either normal or denervated hearts 3
- The drug "does not appear to have a vagal blocking action" 4
Histamine-Related Tachycardia: A Caveat
The only scenario where tachycardia may occur with atracurium is through histamine release, not direct cardiac effects:
- High doses (1.2 mg/kg) can cause histamine release leading to hypotension and compensatory tachycardia 5
- This occurs with rapid bolus administration or doses exceeding 0.6 mg/kg 6
- Slow administration over 75 seconds prevents histamine release and abolishes the hemodynamic response 6
- Pretreatment with H1/H2 antagonists can prevent the response 6
Risk Mitigation for Histamine Release
In patients at higher risk (cardiovascular disease, history of anaphylaxis):
- Use lower initial doses (0.3-0.4 mg/kg) 1
- Administer slowly over 1 minute or in divided doses 1
- Consider H1/H2 antagonist pretreatment 6
Comparison to Other Neuromuscular Blockers
According to 2016 Critical Care Medicine guidelines 2:
- Pancuronium: Prominent vagolytic actions causing dose-dependent tachycardia; avoided in coronary artery disease
- Rocuronium: Causes tachycardia in up to 30% of patients via vagal receptor inhibition
- Vecuronium: Minimal cardiac effects; rare bradycardia reported
- Cisatracurium: May block M2 vagal receptors but tachycardia not clinically important
- Atracurium: No vagolytic activity; bradycardia more common than tachycardia
Bottom Line
Atracurium is cardiovascularly stable regarding heart rate. Any tachycardia observed is secondary to histamine-mediated hypotension with compensatory response, not a direct drug effect. When administered at recommended doses (≤0.6 mg/kg) and given slowly, atracurium maintains heart rate stability and may actually be associated with relative bradycardia compared to agents with vagolytic properties.