Crystallization of short-acting and intermediate-acting local anesthetics when mixed with adjuvants: a semiquantitative light microscopy analysis.

(ρ=0.57 (p=0.0003)) CONCLUSIONS: Our study revealed high grades of crystallization in lidocaine/mepivacaine-bicarbonate and mepivacaine-dexamethasone mixtures, although these were previously considered safe for local, perineural or neuraxial use. Our findings cast particular doubt on the safety of preparing these formulations for later use.