The local anesthetic agent most frequently used in combination with vasoconstrictors such as epinephrine is Lidocaine.

- Lidocaine is a widely preferred local anesthetic due to its rapid onset of action, intermediate duration, and excellent safety profile.
- The addition of a vasoconstrictor like epinephrine prolongs the anesthetic effect by constricting blood vessels, which reduces systemic absorption of the anesthetic, minimizes bleeding in the surgical site, and decreases the potential for toxicity.

- While other local anesthetics such as bupivacaine, prilocaine, and mepivacaine can also be used with vasoconstrictors, Lidocaine's versatility and favorable characteristics make it the most commonly utilized agent in clinical practice.

Key points:
- Lidocaine has a rapid onset and moderate duration.
- Epinephrine acts as a vasoconstrictor to prolong anesthesia and decrease bleeding.
- Combination improves safety by reducing systemic absorption.
- Other agents are available but Lidocaine remains the standard first-line choice.

Reference: Basic and Clinical Pharmacology, 15th Edition, Chapter 28, Local Anesthetics, Page 340-345