Sugammadex: Effect as Antagonist in Anesthesia

Sugammadex (brand name Bridion) is a modified gamma cyclodextrin used in anesthesia as a specific antagonist of steroidal non-depolarizing muscle relaxants such as rocuronium and vecuronium. The active substance was approved in Europe in 2008 and has substantially changed the practice of reversing neuromuscular blockade in modern anesthesia. In Germany, sugammadex is today standard equipment in operating rooms and intensive care units, although its use is deliberately controlled due to higher costs compared to the classic antagonist neostigmine.

Sugammadex has enabled particularly rapid and complete reversal of muscle relaxation and thereby offers better patient safety, especially with deep neuromuscular blockade or when rapid restoration of spontaneous breathing is necessary, for example in difficult intubation. The substance works differently from classic cholinesterase inhibitors and therefore offers pharmacological advantages with fewer cholinergic side effects.

Mechanism of Action

Sugammadex is a chemically synthesized modified cyclodextrin with a ring-shaped structure. This structure forms a lipophilic cavity inside that specifically encapsulates rocuronium and vecuronium. The sugammadex steroid complex is very stable, so the muscle relaxant becomes pharmacologically inactive. Since binding occurs in plasma, free muscle relaxant diffuses back from the neuromuscular synapse into the plasma where it becomes bound. This causes neuromuscular blockade to resolve rapidly and completely.

In contrast to cholinesterase inhibitors such as neostigmine, which increase acetylcholine concentration at the synapse and thus competitively displace muscle relaxants, sugammadex binds the muscle relaxant directly. This eliminates the typical cholinergic side effects of neostigmine (bradycardia, bronchospasm, increased salivation). Additionally, sugammadex can reverse even deep neuromuscular blockades, which is not possible with neostigmine.

Pharmacokinetically, sugammadex acts within 2 to 3 minutes after intravenous administration. The sugammadex rocuronium complex is very hydrophilic and is excreted unchanged renally. The elimination half-life is approximately 2 hours with normal renal function. In severe renal insufficiency, use is not recommended because elimination time is significantly prolonged.

Applications

• Reversal of neuromuscular blockade induced by rocuronium or vecuronium following general anesthesia
• Emergency reversal in "Cannot Intubate, Cannot Ventilate" situations with rocuronium
• Reversal of deep neuromuscular blockade in operations requiring complete muscle relaxation until the end of surgery
• Acceleration of emergence phase in short ambulatory procedures to reduce time in the recovery room
• Patients with risk profile such as malignant hyperthermia, myasthenia gravis, elderly patients, or patients with impaired lung function, where rapid and complete reversal is important

Sugammadex is not effective for muscle relaxants from other chemical classes such as atracurium, cisatracurium, mivacurium, or succinylcholine.

Dosage and Administration

Routine reversal of moderate blockade (TOF Count 2): 2 mg per kg body weight intravenously as bolus. Reversal typically within 2 minutes.

Reversal of deep blockade (PTC 1 to 2, TOF 0): 4 mg per kg, reversal in 3 to 5 minutes.

Emergency reversal immediately after rocuronium administration (immediate reversal): 16 mg per kg, reversal in 1.5 minutes. Use only in Cannot Intubate, Cannot Ventilate situations.

Pediatric from 2 years: 2 mg per kg for moderate blockade. Limited data in children under 2 years, individual use.

Administration: intravenously as single bolus over 10 seconds. No dilution is required. After administration, check neuromuscular function with Train of Four (TOF) monitoring.

Renal insufficiency: not recommended in severe impairment (creatinine clearance below 30 ml per minute) and in dialysis patients. Hepatic insufficiency: generally no adjustment required.

Important: after sugammadex administration, extended waiting period before reusing rocuronium or vecuronium. Alternatively, use of other muscle relaxants such as atracurium.

Side Effects

Common: cough, dry mouth, nausea, vomiting, movement disorder, pain at operation site.

Uncommon: allergic reactions, rash, pruritus, transient loss of consciousness, reactivation of muscle blockade from insufficient dose in deep blockade.

Rare to very rare: anaphylaxis and severe allergic reactions (incidence approximately 1 in 5000), bradycardia (significantly rarer than with neostigmine), hypotension, bronchospasm.

Hormonal interaction: Sugammadex can reduce the effectiveness of hormonal contraceptives (birth control pill). Therefore, patients must use additional non-hormonal contraception methods for 7 days after use.

Bradyarrhythmias: caution and EKG monitoring in patients with risk profile.

Drug Interactions

• Toremifene, fusidic acid: compete with sugammadex for steroid binding, can delay reversal.
• Hormonal contraceptives: Sugammadex also binds steroids such as ethinyl estradiol and progesterone, so the pill is considered ineffective for 7 days after use. Additional contraception recommended.
• Other muscle relaxants: observe waiting periods if neuromuscular blockade is needed again after sugammadex, or use alternatives such as atracurium.
• Anticoagulants: in post hoc analysis slight prolongation of aPTT and PT, clinically generally not relevant. Monitoring in at-risk patients.
• CYP450 substrates: no relevant interactions.

Special Precautions

Pregnancy: limited data, use only with strict indication. Breastfeeding: a single use in anesthesia is generally tolerated, minimal transfer into breast milk.

Children: established from 2 years, individual assessment for younger children.

Severe renal insufficiency: not recommended because elimination of sugammadex complex is significantly slowed.

Before use: history of known allergies to sugammadex, hormonal contraception, renal function, cardiac history.

During use: continuous EKG, respiratory monitoring, Train of Four monitoring to assess complete reversal.

After use: postoperative observation in recovery room, as residual muscle blockade may occur despite objectively demonstrable reversal. If signs of renewed muscle weakness, monitoring again and if necessary, another dose of sugammadex.

Lifestyle: after anesthesia, no safety critical activities for 24 hours, no driving or alcohol.

Driving ability: due to residual effect of other anesthetics, do not drive independently for at least 24 hours after anesthesia.

You might also be interested in

• Rocuronium, non-depolarizing muscle relaxant
• Vecuronium, another steroidal muscle relaxant
• Neostigmine, classic cholinesterase inhibitor as reversal
• Atracurium, alternative muscle relaxant in renal insufficiency
• Succinylcholine, depolarizing muscle relaxant

Frequently Asked Questions

Sources

• Gelbe Liste, Sugammadex active substance profile
• BfArM, Federal Institute for Drugs and Medical Devices
• German Society for Anesthesiology and Intensive Care Medicine
• European Medicines Agency, EPAR Bridion