Pharmacokinetics and pharmacokinetic/dynamic relationship of rocuronium bromide in humans

The existing human pharmacokinetic studies have been reviewed and compared with data derived from animals. The earliest study confirms the similarity of rocuronium to vecuronium with respect to the variables derived from the plasma concentration decay curves and the proportion excreted renally. Other studies led to the conclusion that concurrent administration of volatile anaesthetics did not significantly influence rocuronium pharmacokinetics and that the potentiation must be due to an increased sensitivity of the neuromuscular junction.These studies do not provide an explanation for the clinical observation of a more rapid onset of action. One possible explanation was the finding of a more rapid onset of block in the laryngeal muscles than in the adductor pollicis. However, no pharmacokinetic explanation for this observation has emerged. Alternative concepts need to be modelled. There is a need for comparative pharmacokinetic studies which focus on the period immediately following administration of rocuronium and vecuronium.