Local Anesthetic Agents in Dentistry
Duration of Action

LAs’ receptors on the voltage-gated sodium channels are integral membrane proteins. Predictably, the primary determinant of a LA’s duration of action is its protein-binding capacity (Table 1). LAs with high protein-binding capacity bind more tightly to and dissociate more slowly from their receptor sites and, therefore, have a longer duration of action (Table 4).^2-13 Other factors affecting the duration of action of LAs include their lipid solubility, vascularity at the injection site, the presence of a vasoconstrictor in the formulation, and dosing.