DESCRIPTION
For Infiltration and Nerve Block
Rx only
DESCRIPTION
Xylocaine (lidocaine HCl) Injections are sterile, nonpyrogenic, aqueous solutions that contain a local anesthetic agent with or without
epinephrine and are administered parenterally by injection. See INDICATIONS for specific uses.
Xylocaine solutions contain lidocaine HCl, which is chemically designated as acetamide, 2-(diethylamino)-N-(2,6-dimethylphenyl)-,
monohydrochloride and has the molecular wt. 270.8. Lidocaine HCl (C14H22N2O • HCl) has the following structural formula:
Epinephrine is (-) -3, 4-Dihydroxy-a-[(methylamino) methyl] benzyl alcohol and has the molecular wt. 183.21. Epinephrine
(C9H13NO3) has the following structural formula:
Dosage forms listed as Xylocaine-MPF indicate single dose solutions that are Methyl Paraben Free (MPF).
Xylocaine MPF is a sterile, nonpyrogenic, isotonic solution containing sodium chloride. Xylocaine in multiple dose vials: Each mL
also contains 1 mg methylparaben as antiseptic preservative. The pH of these solutions is adjusted to approximately 6.5 (5.0 to 7.0)
with sodium hydroxide and/or hydrochloric acid.
Xylocaine MPF with Epinephrine is a sterile, nonpyrogenic, isotonic solution containing sodium chloride. Each mL contains
lidocaine hydrochloride and epinephrine, with 0.5 mg sodium metabisulfite as an antioxidant and 0.2 mg citric acid as a stabilizer.
Xylocaine with Epinephrine in multiple dose vials: Each mL also contains 1 mg methylparaben as antiseptic preservative. The pH of
these solutions is adjusted to approximately 4.5 (3.3 to 5.5) with sodium hydroxide and/or hydrochloric acid. Filled under nitrogen.

CLINICAL PHARMACOLOGY
Mechanism of Action
Lidocaine HCl stabilizes the neuronal membrane by inhibiting the ionic fluxes required for the initiation and conduction of impulses
thereby effecting local anesthetic action.
Hemodynamics
Excessive blood levels may cause changes in cardiac output, total peripheral resistance, and mean arterial pressure. With central
neural blockade these changes may be attributable to block of autonomic fibers, a direct depressant effect of the local anesthetic agent
on various components of the cardiovascular system, and/or the beta-adrenergic receptor stimulating action of epinephrine when
present. The net effect is normally a modest hypotension when the recommended dosages are not exceeded.
Pharmacokinetics and Metabolism
Information derived from diverse formulations, concentrations and usages reveals that lidocaine HCl is completely absorbed following
parenteral administration, its rate of absorption depending, for example, upon various factors such as the site of administration and
the presence or absence of a vasoconstrictor agent. Except for intravascular administration, the highest blood levels are obtained
following intercostal nerve block and the lowest after subcutaneous administration.

The plasma binding of lidocaine HCl is dependent on drug concentration, and the fraction bound decreases with increasing
concentration. At concentrations of 1 to 4 mcg of free base per mL 60 to 80 percent of lidocaine HCl is protein bound. Binding is
also dependent on the plasma concentration of the alpha-1-acid glycoprotein.
Lidocaine HCl crosses the blood-brain and placental barriers, presumably by passive diffusion.
Lidocaine HCl is metabol