Pharmacodynamics, along with pharmacokinetics (the effect of the body on the drug and the fate of the drug in the body), helps to explain the relationship between volume and response, the action of the drug. The pharmacological response depends on the binding of the drug to the target. The drug concentration at the receptor site affects the effectiveness of the drug.

Drug Targets and Action
Drug Action at Receptors
Pharmacodynamic Representations
Drug-Receptor Binding
Dose-Response Curves
Application: Opioid Potency