- □ (A) Greater risk for toxicity
- □ (B) Longer blockade duration
- □ (C) Faster onset time
Mepivacaine is an intermediate-potency amide local anesthetic that can be used for peripheral nerve blockade. It is commonly available in a 1.5% concentration. When compared to longer-duration agents such as bupivacaine, the following differences are commonly noted:
- Due to multiple factors (including the dissociation constant and commonly used concentrations), the onset time of mepivacaine blockade is significantly faster than bupivacaine.
- Due to decreased protein binding, the duration of action of mepivacaine blockade is about half the duration of a bupivacaine block.
- Because of decreased potency (primarily a function of lipid solubility), mepivacaine is generally considered less toxic than bupivacaine and higher doses can be used. The maximum safe dose of mepivacaine is approximately double that of bupivacaine when used for peripheral nerve blockade.
The addition of epinephrine (1:200,000) will prolong the action of local anesthetics administered for a peripheral nerve block. The extent of this prolongation is greater with intermediate-acting agents such as mepivacaine than with longer-acting agents such as bupivacaine.