Pharmacokinetics of tubocurarine administered by combined i.v. bolus and infusion.

Pharmacokinetic data were used to calculate an i.v. bolus dose and infusion regimen for tubocurarine (dtc). This produced continuous paralysis in 12 anaesthetized patients. In nine of the patients the duration of infusion was sufficient to achieve a "steady-state" dtc concentration in the plasma (mean 1.09 microgram ml-1). At the completion of the infusion, twitch response had been abolished in half of the group, but 30 min later all had a measurable response. All plasma concentrations decreased rapidly after infusion, from a mean of 1.35 microgram ml-1, in either a mono- or bi-exponential manner. In all instances, a two-compartment open model was used to describe the plasma concentration-time data. The pharmacokinetic parameters derived from this study did not differ significantly from those reported for a single dose except that the plasma clearance was less.