Plasma mepivacaine concentrations in patients undergoing third molar surgery

Area of Science:

• Pharmacology
• Dental Anesthesiology
• Toxicology

Background:

• Local anesthetic systemic toxicity (LAST) is primarily linked to elevated drug plasma concentrations.
• This study investigated whether submaximal doses of mepivacaine during intraoral procedures could lead to toxic blood levels.

Purpose of the Study:

• To evaluate plasma concentrations of mepivacaine following administration for third molar surgeries.
• To determine if submaximal doses of mepivacaine can result in toxic systemic levels.

Main Methods:

• Twenty-one patients undergoing third molar surgery were randomized into two groups based on mepivacaine dosage (108 mg or 216 mg with epinephrine).
• Blood samples were collected at multiple time points up to 120 minutes post-anesthesia to measure mepivacaine plasma levels.

Main Results:

• Peak plasma concentrations of mepivacaine varied significantly between patients in both groups (0.77-8.31 μg/mL).
• A twofold increase in mepivacaine dose (1.88 to 3.35 mg/kg) resulted in a proportional increase in mean peak plasma levels (2.33 to 4.01 μg/mL).
• Four patients exceeded the 5 μg/mL toxicity threshold.

Conclusions:

• Toxic levels of mepivacaine are achievable even with submaximal dosing.
• The proportional increase in peak plasma concentrations suggests predictability based on the dose-to-bodyweight ratio.