Sugammadex

Why this drug is interesting

Sugammadex does not work like any other reversal agent. Neostigmine works indirectly, raising acetylcholine to out-compete the blocker at the neuromuscular junction — which is why it needs some spontaneous recovery to build on, why it plateaus, and why it drags an antimuscarinic along to manage the cholinergic side effects.

Sugammadex instead physically removes the drug. It is a doughnut-shaped modified γ-cyclodextrin with a lipophilic core and a hydrophilic exterior; the steroidal ring of rocuronium or vecuronium slots into the cavity and is held there as a 1:1 complex. Encapsulated molecules cannot reach the junction, and the resulting concentration gradient pulls more drug out of the tissues. Reversal is therefore possible from any depth of block, including profound block, in minutes.

Pharmacology

Mechanism

Sugammadex forms a tight, essentially irreversible 1:1 inclusion complex with aminosteroid neuromuscular blocking agents. Affinity is highest for rocuronium, lower for vecuronium, and lower still for pancuronium.

It has no affinity for benzylisoquinolinium agents — atracurium, cisatracurium and mivacurium are unaffected — and no affinity for suxamethonium, which is a depolarising agent with an entirely different structure. This is not a general paralysis antidote.

Kinetics

Onset

Reversal within 1.5–3 minutes depending on dose and depth of block

Metabolism

None — no metabolites of sugammadex have been observed

Elimination half-life

About 2 hours with normal renal function

Clearance

~88 mL/min, essentially renal

Excretion

Over 90% of the dose within 24 hours; 96% in urine, at least 95% as unchanged sugammadex

The complex itself is renally cleared, which is why renal function dominates the cautions: in severe impairment the sugammadex–rocuronium complex persists, and the SmPC does not recommend use.¹

Indications and dosing

Licensed for reversal of neuromuscular blockade induced by rocuronium or vecuronium in adults. In children, sugammadex is only recommended for routine reversal of rocuronium-induced blockade, from birth to 17 years.¹

Children and adolescents

• 2 mg/kg at reappearance of T2 following rocuronium
• 4 mg/kg at 1–2 post-tetanic counts following rocuronium
• Immediate reversal has not been investigated in the paediatric population

Renal impairment

• Mild to moderate (CrCl ≥30 and <80 mL/min) — standard adult dosing
• Severe (CrCl <30 mL/min, including patients requiring dialysis) — not recommended

Re-administering a neuromuscular blocker afterwards

This is the detail most often forgotten, and it has obvious relevance if a reversed patient subsequently needs intubating.

Practical use in the ED

The failed-RSI question

The scenario that draws emergency physicians to sugammadex is the failed rapid sequence induction: rocuronium given, intubation failed, and a wish to return the patient to spontaneous ventilation. Sugammadex 16 mg/kg will reverse the block in around 90 seconds, which sounds like an answer.

That is not an argument against stocking it. Sugammadex has a legitimate place in the ED: reversing rocuronium after a failed intubation where oxygenation is adequate and waking the patient is the chosen plan; reversing accidental or unnecessary paralysis; and enabling neurological examination in a patient who was paralysed before assessment. The distinction is between a controlled decision to wake someone up and a hypoxic emergency.

Adverse effects and interactions

Anaphylaxis

Hypersensitivity reactions including anaphylaxis are recognised, may occur in patients with no prior exposure, and can be fatal.¹ Features are the familiar ones — flushing, urticaria, hypotension, bronchospasm and airway swelling. Sugammadex is now among the more frequently implicated agents in perioperative anaphylaxis, which is a meaningful shift given how widely it is used.

Bradycardia

Recurrence of blockade

An incidence of 0.20% for recurrence of neuromuscular blockade is reported, and it is associated with doses lower than those recommended. Under-dosing to save vials is therefore specifically discouraged — the failure mode is a re-paralysing patient.

Hormonal contraception

Toremifene

Toremifene has relatively high affinity for sugammadex and may displace rocuronium or vecuronium from the complex, potentially delaying recovery in patients who received it on the day of surgery.

Other

Cough, movement during emergence, hypotension, nausea and vomiting are reported. There is no cholinergic side-effect burden, which is one of the drug's real advantages over neostigmine — no bradycardia from the reversal mechanism itself, no need for co-administered antimuscarinic, no bronchial secretions.

Critical appraisal

1. The efficacy evidence is strong and consistent. Sugammadex reverses aminosteroid blockade faster and more completely than neostigmine, and reduces residual postoperative neuromuscular blockade. This is not seriously disputed.
2. Whether that translates into better patient-centred outcomes is much less settled. Residual blockade is a genuine cause of postoperative pulmonary complications, but demonstrating that routine sugammadex reduces mortality or major morbidity has proved harder than demonstrating that it reverses twitches.
3. Much of the pivotal literature is manufacturer-sponsored, as is usual for a patented agent, and the comparator regimens for neostigmine have sometimes been criticised as not reflecting best practice.
4. The emergency medicine use case is largely extrapolated. The dosing evidence comes from anaesthetised, monitored, elective patients with train-of-four monitoring in place. Most EDs have no quantitative neuromuscular monitoring at all, so the T2 and post-tetanic-count triggers that define the 2 and 4 mg/kg doses cannot actually be assessed — which in practice pushes ED use toward the 16 mg/kg dose by default.
5. Cost is a real constraint, and has shaped whether departments stock it more than the pharmacology has.

References

1. 1
   Bridion 100 mg/ml solution for injection — Summary of Product Characteristics. Merck Sharp & Dohme. electronic Medicines Compendium. Sections 4.1–4.5, 5.2. Verified 20 Aug 2026.
2. 2
   Sugammadex — dosing and safety monograph. BNF, NICE. bnf.nice.org.uk
3. 3
   Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth 2015;115(6):827–48.
4. 4
   Hristovska AM, Duch P, Allingstrup M, Afshari A. Efficacy and safety of sugammadex versus neostigmine in reversing neuromuscular blockade in adults. Cochrane Database Syst Rev 2017;8:CD012763.
5. 5
   Min KC, Bondiskey P, Schulz V, et al. Hypersensitivity incidence after sugammadex administration in healthy subjects. Br J Anaesth 2018;121(4):749–57.
6. 6
   Bhavani SS. Sugammadex-associated hypotension, bradycardia, asystole, and death. Anesthesiology 2020;133(6):1372–74. PMC