Which is the only long acting local anesthetic and what is its concentration?

Which is the only long acting local anesthetic and what is its concentration?

• A. Bupivacaine 0.5%
• B. Lidocaine 2%
• C. Prilocaine 4%
• D. Mepivacaine 2%

Answer: (A)

The main idea is that how long a local anesthetic lasts depends on properties like lipid solubility and protein binding; the more lipid-soluble and highly protein-bound the drug is, the longer its effect tends to persist. Among the options, the one with the longest duration is bupivacaine, because it has high potency and strong protein binding, leading to a prolonged nerve blockade. The standard concentration used to achieve this extended effect is 0.5%. This combination gives a long-lasting anesthetic effect, though the onset of action is slower compared with some shorter-acting agents. The other agents listed are shorter- to intermediate-acting and are typically used for faster onset or shorter duration, with their usual uses not achieving the same extended block as the 0.5% bupivacaine preparation.

The main idea is that how long a local anesthetic lasts depends on properties like lipid solubility and protein binding; the more lipid-soluble and highly protein-bound the drug is, the longer its effect tends to persist. Among the options, the one with the longest duration is bupivacaine, because it has high potency and strong protein binding, leading to a prolonged nerve blockade. The standard concentration used to achieve this extended effect is 0.5%. This combination gives a long-lasting anesthetic effect, though the onset of action is slower compared with some shorter-acting agents. The other agents listed are shorter- to intermediate-acting and are typically used for faster onset or shorter duration, with their usual uses not achieving the same extended block as the 0.5% bupivacaine preparation.