Comparative circulating serum levels of mepivacaine with levo-nordefrin and lidocaine with epinephrien.

Expected blood levels of common local anesthetics have been reported for numerous types of injections. Comparative levels of mepivacaine and lidocaine after dental injection have been only partially evaluated. A study was designed to compare the circulating serum level of 36 mgs. of mepivacaine with 1:20,000 levonordefrin (M) and 36 mgs. of lidocaine with 1:100,000 epinephrine (L) in 1.8 cc dental cartridges after standardized's bilateral maxillary infiltrations. Each of five subjects received 1.8 cc of (L) to the left maxillary second bicuspid and 1.8 cc of (M) to the right maxillary second bicuspid at a rate of one cc per minute. The serum was sampled before the injections and at 5, 15, 30, 60, 90, 120 and 240 minute intervals after the injections and analyzed by gas liquid chromatography. The results indicated that the serum level of (M) peaked at 30 minutes, 0.37 μg/ml of serum and (L) had peaks at 15 and 30 minutes, 0.22 μg/ml of serum. This difference was statistically significant, (p <.01) at all times sampled with (M) always resulting in a higher serum level. Serum levels persisted throughout the four hour test period.