The safety and effectiveness of lidocaine depend on proper dosage, correct technique, adequate precautions, and
readiness for emergencies (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.
Xylocaine 2% Jelly should be used with caution in patients with known drug sensitivities. Patients allergic to paraaminobenzoic
acid derivatives (procaine, tetracaine, benzocaine, etc.) have not shown cross sensitivity to lidocaine.
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).
Long-term studies in animals have not been performed to evaluate the carcinogenic potential of lidocaine.
The mutagenic potential of lidocaine has been tested in the Ames Salmonella reverse mutation assay, an in vitro chromosome aberrations assay in human lymphocytes and in an in vivo mouse micronucleus assay. There was no
indication of any mutagenic effect in these studies.
Impairment Of Fertility
The effect of lidocaine on fertility was examined in the rat model. Administration of 30 mg/kg, s.c. (180 mg/m2) to
the mating pair did not produce alterations in fertility or general reproductive performance of rats. There are no studies
that examine the effect of lidocaine on sperm parameters. There was no evidence of altered fertility.
Use In Pregnancy
Pregnancy Category B.
Reproduction studies for lidocaine have been performed in both rats and rabbits. There was no evidence of harm to
the fetus at subcutaneous doses of up to 50 mg/kg lidocaine (300 mg/m2 on a body surface area basis) in the rat model.
In the rabbit model, there was no evidence of harm to the fetus at a dose of 5 mg/kg, s.c. (60 mg/m2 on a body surface
area basis). Treatment of rabbits with 25 mg/ kg (300 mg/m2) produced evidence of maternal toxicity and evidence of
delayed fetal development, including a non-significant decrease in fetal weight (7%) and an increase in minor skeletal
anomalies (skull and sternebral defect, reduced ossification of the phalanges). The effect of lidocaine on post-natal
development was examined in rats by treating pregnant female rats daily subcutaneously at doses of 2, 10, and 50
mg/kg (12, 60, and 300 mg/m2) from day 15 of pregnancy and up to 20 days postpartum. No signs of adverse effects
were seen either in dams or in the pups up to and including the dose of 10 mg/kg (60 mg/m2); however, the number
of surviving pups was reduced at 50 mg/kg (300 mg/m2), both at birth and the duration of lactation period, the effect
most likely being secondary to maternal toxicity. No other effects on litter size, litter weight, abnormalities in the pups
and physical developments of the pups were seen in this study.
A second study examined the effects of lidocaine on post-natal development in the rat that included assessment of the
pups from weaning to sexual maturity. Rats were treated for 8 months with 10 or 30 mg/kg, s.c. lidocaine (60 mg/m2
and 180 mg/m2 on a body surface area basis, respectively). This time period encompassed 3 mating periods. There
was no evidence of altered post-natal development in any offspring; however, both doses of lidocaine significantly
reduced the average number of pups per litter surviving until weaning of offspring from the first 2 mating periods.
There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies
are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Labor And Delivery
Lidocaine is not contraindicated in labor and delivery. Should Xylocaine 2% Jelly be used concomitantly with other
products containing lidocaine, the total dose contributed by all formulations must be kept in mind.
Lidocaine is secreted in human milk. The clinical significance of this observation is unknown. Caution should be
exercised when lidocaine is administered to a nursing woman.
Although the safety and effectiveness of Xylocaine 2% Jelly in pediatric patients have not been established, a study
of 19 premature neonates (gestational age <33 weeks) found no correlation between the plasma concentration of
lidocaine or monoethylglycinexylidide and infant body weight when moderate amounts of lidocaine (i.e. 0.3 mL/kg
of lidocaine gel 20 mg/mL) were used for lubricating both intranasal and endotracheal tubes. No neonate had plasma
levels of lidocaine above 750 mcg/L. Dosages in children should be reduced, commensurate with age, body weight,
and physical condition (see DOSAGE AND ADMINISTRATION).