Letters to the Editor: Letters & Announcements
A dose of sugammadex that cannot bind all the available rocuronium will most certainly be inadequate. As an example, De Boer et al. (1) were unable to alter the duration of rocuronium in the monkey when a 1 mg/kg dose of sugammadex was given 1 min after 0.5 mg/kg of rocuronium. Increasing the dose to 2.5 mg/kg (40% greater than the equimolar dose of rocuronium) decreased the duration of the rocuronium block but had a prolonged onset.
The calculated equimolar dose of sugammadex is the theoretical minimum required to reverse a recently induced rocuronium block. After injection, some sugammadex will bind other steroids or be renally excreted. Therefore, some multiple of the equimolar dose will be required to fully reverse the effect of rocuronium and this multiple will have to be even greater for rapid onset. The calculated equimolar dose of sugammadex is not the same as a clinically effective dose. This will always be greater. Dr. Kopman's skepticism of the efficacy of basing clinical dosing on the calculated equimolar dose is entirely warranted. I thank Dr. Kopman (2) for his thoughtful comments on our study (3).
Scott Groudine, MD
Department of Anesthesiology
Albany Medical Center
1. De Boer H, van Egmond J, van de Pol F, Bom A, Booij LHDJ. Reversal of profound neuromuscular blockade by sugammadex in anesthetized rhesus monkeys. Anesthesiology 2006;104:718–23
2. Kopman AF. Sugammadex-rocuronium dosing. Anesth Analg 2007;105:883–4
3. Groudine SB, Soto R, Lien C, Drover D, Roberts K. A randomized, dose-finding, phase II study of the selective relaxant binding drug, sugammadex, capable of safely reversing profound rocuronium-induced neuromuscular block. Anesth Analg 2007;104:555–62