Mepivacaine Hydrochloride

Local anesthetics (LAs: articaine, lidocaine, bupivacaine, and mepivacaine) are essential for dental pain management. However, there are concerns that the lipophilic LAs could cross into breast milk causing toxicity to the infant. Our objective was to establish a multi-analyte LC-MS/MS method for the concurrent quantification of local anesthetics (LAs) in human plasma and breast milk, clarifying the transfer of LAs from plasma to breast milk, thereby offering crucial data for the safe assessment of LAs during the nursing period. Sample preparation for plasma and breast milk involved protein precipitation and a single dilution step. The chromatographic analysis was conducted using an ACQUITY UPLC BEH C18 column. Detection was facilitated by a triple quadrupole mass spectrometer employing positive electrospray ionization. The method demonstrated excellent linearity for articaine, mepivacaine, and bupivacaine across the range of 0.5 to 500 ng/mL, and for lidocaine from 1.0 to 1000 ng/mL in both plasma and breast milk, with correlation coefficients (R2) of 0.99 or higher. The method was effectively utilized in the analysis of samples from three nursing mothers who received dental treatment involving LAs. Articaine and lidocaine excretion in milk was confirmed, but it presented no significant safety risks to the breastfed infants.

To compare the efficacy of low-volume (5-mL) locoregional retrobulbar anesthesia (“retrobulbar block”) by use of 3 commercial local anesthetic formulations.

8 healthy adult mares.

A block-randomized, masked, controlled design was used. A single ultrasound-guided retrobulbar block was performed with 2% lidocaine, 2% mepivacaine, or 0.5% bupivacaine (n = 5 eyes/group). Contralateral eyes served as untreated controls. End points performed at baseline and time intervals up to 24 hours postblock included the following: assessment of neurophthalmic reflexes/responses, intraocular pressure, and vertical pupil diameter measurement, corneal and periocular esthesiometry, and observation for adverse effects.

Low-volume block did not result in increased intraocular pressure or other adverse effects at any time point in any treatment group. Statistically significant corneal anesthesia (P < .001) was observed 1 minute after block in all groups, persisting through 4 hours after lidocaine or mepivacaine block and through 24 hours after bupivacaine block. Clinically significant periocular anesthesia was not observed in any group. Significant vertical pupil diameter increase (P < .05) was observed for up to 4 hours after lidocaine or mepivacaine block and 6 hours after bupivacaine block.

Low-volume retrobulbar block with any of the 3 local anesthetic drugs evaluated was not associated with adverse effects. In terms of efficacy, mepivacaine block showed no clinical advantage over lidocaine block. However, bupivacaine block induced comparatively rapid and sustained corneal anesthesia. In comparison to published findings using a larger injection volume, low-volume retrobulbar block with lidocaine produced clinically comparable corneal anesthesia. However, periocular soft tissue anesthesia was not achieved with any local anesthetic drug at low volume.