We appreciate the interest of Nigrovic et al.  in our work. The pharmacokinetic parameters that are presented in our article1are the results of a noncompartmental pharmacokinetic analysis. The authors of the letter are looking for parameters of a pharmacokinetic modeling analysis and wonder whether such an approach was attempted. The answer is yes. In addition to the descriptive manner in which the pharmacokinetic data of this trial were presented in the article, the plasma concentration–time data of sugammadex (Org 25969) and rocuronium were also analyzed elaborately as part of a mechanism-based pharmacokinetic–pharmacodynamic modeling analysis. The model developed in the latter analysis describes not only the time course of plasma concentrations of sugammadex, rocuronium, and the complex formed between sugammadex and rocuronium, but also the resulting time course of neuromuscular block. The results of the development and validation of that model will be the subject of a separate publication.

With regard to the second point that was raised, we agree that it may have been informative from a scientific point of view to discuss the doses in molar units, but because in practice sugammadex is dosed in units of mg/kg, we believe that it is more appropriate to use that unit in publications.

*Pharmerit BV, Rotterdam, The Netherlands. nhouwing@pharmerit.com

Gijsenbergh F, Ramael S, Houwing N, van Iersel T: First human exposure of Org 25969, a novel agent to reverse the action of rocuronium bromide. Anesthesiology 2005; 103:695–703