Sugammadex–Rocuronium Dosing

To the Editor: In their recent dose-finding study, Groudine et al. (1) note that the molecular weight of sugammadex is 3.6 times that of rocuronium. They postulate that these drugs bind in a 1:1 ratio, and that as a result 1.8 mg/kg sugammadex should encapsulate all the rocuronium administered in a 0.50 mg/kg dose. This hypothesis is perhaps overly simplistic as it does not explain all available clinical data. Following rocuronium 1.2 mg/kg, sugammadex 4.0 mg/kg does not produce prompt and complete neuromuscular block if administered 3 min (2) or 5 min later (3). Until all the data are in, I would suggest that it is premature to suggest that when sugammadex and rocuronium are administered in equimolar amounts that complete reversal of neuromuscular block will necessarily ensue. Aaron F. Kopman, MD Department of Anesthesiology (N.R. 408) Saint Vincent's Hospital Manhattan New York, NY [email protected] or [email protected]