The safety and effectiveness of lidocaine depend on proper dosage, correct
technique, adequate precautions, and readiness for emergencies. Resuscitative
equipment, oxygen and other resuscitative drugs should be available for immediate
use. (See WARNINGS and ADVERSE REACTIONS.)
The lowest dosage that results in effective anesthesia should be used to avoid
high plasma levels and serious adverse effects. Repeated doses of lidocaine
may cause significant increases in blood levels with each repeated dose, because
of slow accumulation of the drug or its metabolites. Tolerance to elevated blood
levels varies with the status of the patient. Debilitated, elderly patients,
acutely ill patients, and children should be given reduced doses commensurate
with their age and physical status. Lidocaine should also be used with caution
in patients with severe shock or heart block.
Local anesthetic solutions containing a vasoconstrictor
should be used cautiously and in carefully circumscribed quantities in areas of
the body supplied by end arteries or having otherwise compromised blood supply.
Patients with peripheral vascular disease and those with hypertensive vascular
disease may exhibit exaggerated vasoconstrictor response. Ischemic injury or
necrosis may result. Preparations containing a vasoconstrictor should be used
with caution in patients during or following the administration of potent
general anesthetic agents, since cardiac arrhythmias may occur under such
Careful and constant monitoring of cardiovascular and
respiratory (adequacy of ventilation) vital signs and the patient's state of
consciousness should be accomplished after each local anesthetic injection. It
should be kept in mind at such times that restlessness, anxiety, tinnitus, dizziness,
blurred vision, tremors, depression or drowsiness may be early warning signs of
central nervous system toxicity.
Since amide-type local anesthetics are metabolized by the
liver, 4% Xylocaine-MPF Sterile Solution should be used with caution in patients
with hepatic disease.
Patients with severe hepatic disease, because of their
inability to metabolize local anesthetic normally, are at greater risk of
developing toxic plasma concentrations. 4% Xylocaine-MPF Sterile Solution
should also be used with caution in patients with impaired cardiovascular
function since they may be less able to compensate for functional changes
associated with the prolongation of A-V conduction produced by these drugs.
Use in Ophthalmic Surgery
When local anesthetic solutions are employed for retrobulbar
block, lack of corneal sensation should not be relied upon to determine whether
or not the patient is ready for surgery since corneal sensation usually
precedes clinically acceptable external ocular muscle akinesia.
Many drugs used during the conduct of anesthesia are
considered potential triggering agents for familial malignant hyperthermia.
Since it is not known whether amide-type local anesthetics may trigger this
reaction and since the need for supplemental general anesthesia cannot be
predicted in advance, it is suggested that a standard protocol for management
should be available. Early unexplained signs of tachycardia, tachypnea, labile
blood pressure and metabolic acidosis may precede temperature elevation. Successful
outcome is dependent on early diagnosis, prompt discontinuance of the suspect
triggering agent(s) and institution of treatment, including oxygen therapy,
indicated supportive measures and dantrolene (consult dantrolene sodium intravenous package insert before using).
Lidocaine should be used with caution in persons with known
drug sensitivities. Patients allergic to para-aminobenzoic acid derivatives
(procaine, tetracaine, benzocaine, etc.) have not shown cross sensitivity to
Use in the Head and Neck Area
Small doses of local anesthetics injected into the head and neck area, including
retrobulbar, dental and stellate ganglion blocks, may produce adverse reactions
similar to systemic toxicity seen with unintentional intravascular injections
of larger doses. Confusion, convulsions, respiratory depression and/or respiratory
arrest, and cardiovascular stimulation or depression have been reported. These
reactions may be due to intra-arterial injection of the local anesthetic with
retrograde flow to the cerebral circulation. Patients receiving these blocks
should have their circulation and respiration monitored and be constantly observed.
Resuscitative equipment and personnel for treating adverse reactions should
be immediately available. Dosage recommendations should not be exceeded. (See
DOSAGE AND ADMINISTRATION.)
Carcinogenesis, Mutagenesis, Impairment of Fertility
Studies of lidocaine in animals to evaluate the carcinogenic
and mutagenic potential or the effect on fertility have not been conducted.
Use in Pregnancy
Teratogenic Effects - Pregnancy Category B
Reproduction studies have been performed in rats at doses up to 6.6 times
the human dose and have revealed no evidence of harm to the fetus caused by
lidocaine. There are, however, no adequate and well-controlled studies in pregnant
women. Animal reproduction studies are not always predictive of human response.
General consideration should be given to this fact before administering lidocaine
to women of childbearing potential, especially during early pregnancy when maximum
organogenesis takes place.
Labor and Delivery
Lidocaine is not contraindicated in labor and delivery.
Should 4% Xylocaine-MPF Sterile Solution be used concomitantly with other
products containing lidocaine, the total dose contributed by all formulations
must be kept in mind.
It is not known whether this drug is excreted in human milk.
Because many drugs are excreted in human milk, caution should be exercised when
lidocaine is administered to a nursing woman.
Dosages in children should be reduced, commensurate with age
and body weight. See DOSAGE AND ADMINISTRATION.