Identification of glycinexylidide in patients treated with intravenous lidocaine

Glycinexylidide (GX) has been identified in the urine of 8 patients treated with intravenous infusions of lidocaine. The concentration of GX ranged from 1.0 to 2.7 Ilg per milliliter in the plasma of 3 of these patients. This di‐desethylated product of lidocaine metabolism, like the mono‐desethylated metabolite, monoethylglycinexylidide (MEGX) also has local anesthetic activity. Both compounds may contribute to central nervous system (CNS) toxicity in some patients treated with lidocaine.