ized rapidly by the liver, and metabolites and unchanged drug are excreted by the kidneys.
Biotransformation includes oxidative N-dealkylation, ring hydroxylation, cleavage of the amide linkage, and conjugation. Ndealkylation,
a major pathway of biotransformation, yields the metabolites monoethylglycinexylidide and glycinexylidide. The
pharmacological/toxicological actions of these metabolites are similar to, but less potent than, those of lidocaine HCl. Approximately
90% of lidocaine HCl administered is excreted in the form of various metabolites, and less than 10% is excreted unchanged. The
primary metabolite in urine is a conjugate of 4-hydroxy-2,6-dimethylaniline.
The elimination half-life of lidocaine HCl following an intravenous bolus injection is typically 1.5 to 2 hours. Because of the rapid
rate at which lidocaine HCl is metabolized, any condition that affects liver function may alter lidocaine HCl kinetics. The half-life
may be prolonged two-fold or more in patients with liver dysfunction. Renal dysfunction does not affect lidocaine HCl kinetics but
may increase the accumulation of metabolites.
Factors such as acidosis and the use of CNS stimulants and depressants affect the CNS levels of lidocaine HCl required to produce
overt systemic effects. Objective adverse manifestations become increasingly apparent with increasing venous plasma levels above 6
mcg free base per mL. In the rhesus monkey arterial blood levels of 18 to 21 mcg/mL have been shown to be threshold for convulsive
activity.
INDICATIONS & USAGE
Xylocaine (lidocaine HCl) Injections are indicated for production of local or regional anesthesia by infiltration techniques such
as percutaneous injection and intravenous regional anesthesia by peripheral nerve block techniques such as brachial plexus and
intercostal and by central neural techniques such as lumbar and caudal epidural blocks, when the accepted procedures for these
techniques as described in standard textbooks are observed.
CONTRAINDICATIONS
Lidocaine HCl is contraindicated in patients with a known history of hypersensitivity to local anesthetics of the amide type.
WARNINGS
XYLOCAINE INJECTIONS FOR INFILTRATION AND NERVE BLOCK SHOULD BE EMPLOYED ONLY BY CLINICIANS
WHO ARE WELL VERSED IN DIAGNOSIS AND MANAGEMENT OF DOSE-RELATED TOXICITY AND OTHER ACUTE
EMERGENCIES THAT MIGHT ARISE FROM THE BLOCK TO BE EMPLOYED AND THEN ONLY AFTER ENSURING THE
IMMEDIATE AVAILABILITY OF OXYGEN, OTHER RESUSCITATIVE DRUGS, CARDIOPULMONARY EQUIPMENT AND
THE PERSONNEL NEEDED FOR PROPER MANAGEMENT OF TOXIC REACTIONS AND RELATED EMERGENCIES (see
also ADVERSE REACTIONS and PRECAUTIONS). DELAY IN PROPER MANAGEMENT OF DOSE-RELATED TOXICITY,
UNDERVENTILATION FROM ANY CAUSE AND/OR ALTERED SENSITIVITY MAY LEAD TO THE DEVELOPMENT OF
ACIDOSIS, CARDIAC ARREST AND, POSSIBLY, DEATH.
Intra-articular infusions of local anesthetics following arthroscopic and other surgical procedures is an unapproved use, and there have
been post-marketing reports of chondrolysis in patients receiving such infusions. The majority of reported cases of chondrolysis have
involved the shoulder joint; cases of gleno-humeral chondrolysis have been described in pediatric and adult patients following intraarticular
infusions of local anesthetics with and without epinephrine for periods of 48 to 72 hours. There is insufficient information
