Which local anesthetic has the highest level of protein binding?

Bupivacaine is recognized for having the highest level of protein binding among local anesthetics. This characteristic significantly influences its pharmacokinetics and duration of action. High protein binding allows bupivacaine to remain more stable in systemic circulation, leading to a prolonged effect. Enhanced binding to plasma proteins means that more of the drug is "stored" and released slowly, which is advantageous in clinical situations where extended pain relief is desired.

In contrast, other local anesthetics like procaine, lidocaine, and mepivacaine have lower protein binding percentages, resulting in shorter durations and less sustained effects. For example, while lidocaine and mepivacaine are effective for regional anesthesia, their shorter half-lives and lower tissue retention rates do not provide the prolonged effects that bupivacaine can offer, making it a preferred choice in situations requiring longer-lasting anesthesia.