Local anesthetics work by preventing the entry of sodium ions into neurons, inhibiting the propagation of action potentials and conduction in peripheral nerves. There are two theories for how this occurs - the non-specific membrane expansion theory where the anesthetic attaches to and swells the cell membrane blocking sodium channels, and the specific receptor theory where it binds to receptors on sodium gates. Common local anesthetics discussed include lidocaine, prilocaine, articaine, and bupivacaine, each with different properties in terms of onset, duration, and maximum dosage.