Oral Administration : Dosing Regimen Strategy

In this step, Prof. Lee introduces several equations based on assumptions that some parameters are unchanged.

First, if we assume that the therapeutic concentration (Css) and the bioavailability (F) are the same, the initial dose for patients in renal failure will be related to the clearance (Cl) and the dosing interval (tau).

Following that, if we assume the dosing interval remains unchanged, dose will be reduced by a factor of clearance ratio.

Besides, if dose and frequency are adjusted concurrently, dosing rate is to be reduced.

Finally, elimination rate constant and half-life are more readily available than total clearance. Assuming that the volume of distribution is the same for patients with renal failure and normal kidney function, we can use the K ratio to adjust dosing regimen.