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.
GLYDO should be used with caution in patients with known drug
sensitivities. Patients allergic to para-aminobenzoic acid derivatives
(procaine, tetracaine, benzocaine, etc.) have not shown cross sensitivity to
Many drugs used during the conduct of anesthesia are
considered potential triggering agents for familial malignant hyperthermia.ÃÂ 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
Information For Patients
Inform patients that use of local anesthetics may cause methemoglobinemia,
a serious condition that must be treated promptly. Advise patients or
caregivers to seek immediate medical attention if they or someone in their care
experience the following signs or symptoms: pale, gray, or blue colored skin (cyanosis);
headache; rapid heart rate; shortness of breath; lightheadedness; or fatigue.
When topical anesthetics are used in the mouth, the
patient should be aware that the production of topical anesthesia may impair
swallowing and thus enhance the danger of aspiration. For this reason, food
should not be ingested for 60 minutes following use of local anesthetic
preparations in the mouth or throat area. This is particularly important in
children because of their frequency of eating.
Numbness of the tongue or buccal mucosa may enhance the
danger of unintentional biting trauma. Food and chewing gum should not be taken
while the mouth or throat area is anesthetized.
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 Specific Populations
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
Labor And Delivery
Lidocaine is not contraindicated in labor and delivery.
Should GLYDO 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 GLYDO 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