LIQUID LIDOCAINE HCI 2%

Lidocaine HCl 2% Pharmacokinetics and Metabolism Lidocaine HCl is rapidly and completely absorbed following parenteral administration. Absorption rates vary based on the administration site and the presence of a vasoconstrictor agent. Blood levels peak highest following intercostal nerve block and lowest after subcutaneous administration. Lidocaine HCl binds to plasma proteins in a concentration-dependent manner, with 60-80% bound at concentrations of 1 to 4 mcg/mL. Binding is also influenced by the plasma concentration of alpha-1-acid glycoprotein. Lidocaine HCl crosses the blood-brain and placental barriers through passive diffusion. The liver rapidly metabolizes it, and both metabolites and unchanged drug are excreted by the kidneys. Biotransformation includes oxidative N-dealkylation, ring hydroxylation, cleavage of the amide linkage, and conjugation. Major metabolites include monoethylglycinexylidide and glycinexylidide, which are less potent than the parent compound. Approximate