Sugammadex vs Neostigmine: When Which

Neostigmine: acetylcholinesterase inhibitor. Increases ACh at the NMJ, outcompetes the non-depolarizing NMB. Indirect, slow, requires some recovery already (TOF count ≥2). Always paired with anticholinergic (glycopyrrolate or atropine) to block the muscarinic effects (bradycardia, bronchospasm, salivation). Sugammadex: γ-cyclodextrin that physically encapsulates rocuronium or vecuronium in plasma → renal excretion. Direct, fast, works at any depth of block including profound. No anticholinergic needed.

Sugammadex (rocuronium or vecuronium only — NOT cisatracurium): 2 mg/kg if TOF count ≥2 (moderate block); 4 mg/kg if PTC ≥1-2 (deep block); 16 mg/kg for emergent reversal (cannot intubate, must wake patient). Neostigmine: 30-50 mcg/kg IV (max 5 mg) WITH glycopyrrolate 7-15 mcg/kg or atropine 15 mcg/kg. Requires TOF count ≥2-4 to work reliably; can prolong block if given too early. Edrophonium is faster onset but not used much.

(1) Profound block at end of case (PTC ≤1) — neostigmine doesn't work reliably here; sugammadex does. (2) Cannot-intubate emergency — sugammadex 16 mg/kg reverses 1.2 mg/kg rocuronium in 90-180 sec, faster than succinylcholine wears off. (3) Severe asthmatics (no muscarinic effect; no bronchospasm risk). (4) Bradycardic patients (no muscarinic stimulation; no atropine needed). (5) Patients with high vagal tone where glycopyrrolate has caused issues. (6) When OR turnover matters. Trade-off: cost (~$100-200/dose vs <$10 for neostigmine), oral contraceptive interaction (advise backup contraception 7 days), rare anaphylaxis.

(1) Routine reversal at adequate depth (TOF ≥2). (2) Cisatracurium / atracurium / mivacurium reversal — sugammadex doesn't work on benzylisoquinolines. (3) Succinylcholine — neither works; just wait. (4) Cost-conscious environments where sugammadex availability is restricted to specific indications. (5) Very-prolonged cases where rocuronium has been allowed to wear off near-fully. Use TOF ratio ≥0.9 confirmed by quantitative monitor before extubation regardless of which drug.

TOF ratio <0.9 at extubation = residual paralysis. Causes: pharyngeal weakness → aspiration; reduced HVR → post-op respiratory depression; weakened cough → atelectasis + pneumonia. Studies estimate 20-40% of patients arrive in PACU with TOF <0.9 if only clinical signs (head lift, hand grip) used. Quantitative monitoring + adequate reversal dose + patience reduces this to <5%. Modern guideline (ASA + ESAIC): use quantitative TOF monitoring + reverse to TOF ≥0.9 in EVERY patient receiving non-depolarizing NMB.