Can Atracurium Be Reversed by Sugammadex?
No, sugammadex cannot reverse atracurium-induced neuromuscular blockade and should not be used for this purpose. Atracurium is a benzylisoquinoline muscle relaxant, and sugammadex only works on steroidal neuromuscular blocking agents (rocuronium and vecuronium). 1
Mechanism of Action Explains the Limitation
Sugammadex is a gamma cyclodextrin that specifically encapsulates steroidal neuromuscular blocking agents (rocuronium and vecuronium) through selective molecular binding. 1 This chemical structure allows it to form a 1:1 complex only with steroidal compounds, making it completely ineffective against benzylisoquinoline agents like atracurium or cisatracurium. 2, 3, 4
Correct Reversal Agent for Atracurium
For atracurium-induced neuromuscular blockade, neostigmine is the appropriate reversal agent. 1
Neostigmine Reversal Algorithm for Atracurium:
Assess Train-of-Four (TOF) responses at the adductor pollicis using quantitative monitoring 1
If TOF responses = 4: Administer neostigmine 0.04 mg/kg with atropine 0.02 mg/kg 1
- Expected efficacy (TOF ratio ≥0.9) in 10-20 minutes 1
If TOF responses < 4: Wait and maintain anesthesia, then reassess 1
- Neostigmine cannot effectively reverse deep blockade 5
For very shallow blockade (TOF ratio 0.4-0.6): Consider reducing neostigmine dose by half (to approximately 0.02 mg/kg) 1
Critical Clinical Pitfalls
Neostigmine must not be administered when fewer than 2 TOF responses are present, as it will be ineffective and may cause cholinergic side effects without achieving adequate reversal. 1, 5 This is a fundamental difference from sugammadex, which can reverse any depth of steroidal neuromuscular blockade. 2, 3
Quantitative neuromuscular monitoring is mandatory to determine the appropriate timing for neostigmine administration and to confirm adequate recovery (TOF ratio ≥0.9). 1, 6, 5 Clinical assessment alone is insufficient to detect residual neuromuscular blockade, which increases postoperative morbidity and mortality. 6
Why This Matters Clinically
Neostigmine should not be withdrawn from clinical practice specifically because it remains the only reversal agent effective against atracurium and cisatracurium. 3 While sugammadex offers superior speed and predictability for steroidal agents, the continued availability of benzylisoquinoline muscle relaxants (particularly in patients with renal or hepatic failure) necessitates maintaining neostigmine as a reversal option. 1, 5, 7