Rational Dosing & the Time Course of Drug Action
The goal of therapeutics is to achieve a desired beneficial effect with minimal adverse effects.
When a medicine has been selected for a patient, the clinician must determine the dose that most closely achieves this goal.
A rational approach to this objective combines the principles of pharmacokinetics with pharmacodynamics to understand the dose-effect relationship
Pharmacodynamics governs the concentration-effect part of the relationship, whereas pharmacokinetics deals with the dose-concentration part (Holford & Sheiner, 1981).
The pharmacodynamic concepts of maximum response and sensitivity determine the magnitude of the effect at a particular concentration.
The pharmacokinetic processes of input, distribution, and elimination determine how rapidly and for how long the target organ will be exposed to the drug.
