Anesthesiology APPLIED Exam › Pharmacology, equipment and physics

Sugammadex

Pharmacology, equipment and physics·~4 min read· Physician-reviewed✓ Sourced · 3

Stem

A 31-year-old woman, 64 kg, is finishing a laparoscopic cholecystectomy under general anesthesia with sevoflurane and rocuronium. The surgeon asked for deeper relaxation 15 minutes ago and she received another 20 mg of rocuronium. The quantitative monitor at the adductor pollicis now shows no train-of-four response and a post-tetanic count of 2. She takes a combined oral contraceptive pill.

Question

How will you reverse her neuromuscular blockade, and what will you tell her afterward?

Ideal answer

HeadlineShe has a deep block, so not neostigmine: sugammadex 4 mg/kg by actual body weight for a post-tetanic count of 1 to 2, about 256 mg.¹

Sugammadex 4 mg/kg now, about 256 mg. It encapsulates rocuronium, so it works at depths neostigmine cannot;¹ I keep her anesthetized while it acts.
Extubate only at a train-of-four ratio ≥0.9, measured quantitatively at the adductor pollicis; clinical signs alone are not enough.²
Atropine ready; I watch heart rate and pressure. Marked bradycardia, sometimes progressing to arrest, has occurred within minutes;¹ I also watch for hypersensitivity.
Counsel her plainly about her pill. Sugammadex can make it less effective, as if she had missed a dose, so she uses a non-hormonal backup method, such as condoms, for the next 7 days.¹ I document that conversation.

Breaking down the answer

Dose to the monitor — 2 mg/kg once T2 has reappeared, 4 mg/kg at 1–2 post-tetanic counts, and 16 mg/kg for immediate reversal about 3 minutes after 1.2 mg/kg rocuronium.¹ Naming the depth before the dose shows organized reasoning.
Guideline backing — the 2023 ASA guideline recommends sugammadex over neostigmine at deep, moderate and shallow depths, and neostigmine only as a reasonable alternative at minimal depth (train-of-four ratio about 0.4 to below 0.9).²
Actual body weight — in obese patients, dosing by actual rather than ideal weight gave faster recovery.¹
Know what it cannot do — it does not reverse succinylcholine or benzylisoquinolinium relaxants.¹
Renal failure — it is not recommended when creatinine clearance is below 30 mL/min, because the complex is renally cleared.¹
Re-paralysis is harder — after sugammadex, rocuronium 1.2 mg/kg can be given after 5 minutes, but the usual 0.6 mg/kg dose needs a 4-hour wait.¹ That matters if the surgeon needs to go back in.

Follow-up question

Two minutes after the sugammadex, before extubation, her blood pressure falls to 68/35, her heart rate rises to 128, peak airway pressure climbs, and hives spread across her chest.

What do you do?

Follow-up answer

HeadlineAnaphylaxis, and the timing makes sugammadex the likely trigger: rare but real, 0.3% of 299 volunteers.¹ I call for help and tell the surgeon.

She stays intubated on 100% oxygen. Epinephrine 50 mcg IV, repeated to effect with an infusion if needed, and a rapid 500–1000 mL fluid bolus with her legs raised.³ Bronchospasm gets epinephrine first, then an inhaled bronchodilator; antihistamine and steroid only once she is stabilizing. Tryptase once stable, again at 1–4 hours and at least 24 hours later.³ I extubate only with a train-of-four ratio of at least 0.9 and airway swelling excluded, and refer her for allergy testing.

Pitfalls that cost points

Giving neostigmine to a patient with no twitches.
Extubating without a quantitative train-of-four ratio of at least 0.9.

Rapid-fire

Q: Which lab test does sugammadex interfere with? A: Serum progesterone.¹

Q: What does it do to coagulation tests? A: It raises aPTT and PT/INR transiently, up to about 25% for up to an hour.¹

Q: Why can blockade recur after sugammadex? A: Other drugs, such as toremifene, can displace rocuronium from the complex.¹

Q: Why not monitor at the eye? A: The ASA guideline recommends against eye muscles; it recommends the adductor pollicis.²

Q: From what age is it approved? A: The label covers pediatric patients from birth.¹

Numbers to know

Item	Value
T2 present	2 mg/kg¹
PTC 1–2	4 mg/kg¹
Immediate reversal after rocuronium 1.2 mg/kg	16 mg/kg¹
Extubation threshold	TOF ratio ≥0.9²
Backup contraception	7 days¹
Not recommended	CrCl <30 mL/min¹
Rocuronium 0.6 mg/kg after sugammadex	Wait 4 h¹

Sources

1.BRIDION (sugammadex) injection prescribing information · FDA / DailyMed · dailymed.nlm.nih.gov
2.New Practice Guidelines for Neuromuscular Blockade · APSF, 2023 · apsf.orgReproduces the recommendations of the 2023 ASA Practice Guidelines for Monitoring and Antagonism of Neuromuscular Blockade.
3.Perioperative anaphylaxis treatment algorithm · Resuscitation Council UK / Association of Anaesthetists, 2024 · resus.org.uk

Facts on this page were checked against these sources on Oct 15, 2026. Guidelines change; confirm doses against current institutional protocols.