When can the infusion period be safely ignored in the estimation of pharmacokinetic parameters of drugs in humans?

We describe a simple and rapid method to determine the amount by which the area under the curve (AUC) is underestimated when a drug is given by i.v. infusion but the infusion period is ignored and the post-infusion data are analysed as if they derive from a bolus injection. Charts are provided that allow the investigator to determine the approximate underestimation for drugs following the one- and two-compartment models, and hence to decide whether it is acceptable to ignore the infusion period in a given case (e.g., underestimation < 5% or 10%). Equations are also provided that allow the exact underestimation to be calculated, together with the true value of the AUC.