LIDOSITE TOPICAL SYSTEM KIT

Clinical safety rating: caution

Comprehensive clinical and safety monograph for LIDOSITE TOPICAL SYSTEM KIT (LIDOSITE TOPICAL SYSTEM KIT).

How it works

Lidocaine is an amide-type local anesthetic that stabilizes neuronal membranes by blocking voltage-gated sodium channels, thereby inhibiting the initiation and conduction of nerve impulses.

What the body does with it

Metabolism	Lidocaine is primarily metabolized in the liver via oxidative N-dealkylation by CYP1A2 and CYP3A4 to monoethylglycinexylidide (MEGX) and glycinexylidide (GX), both active metabolites. Further metabolism involves hydrolysis and conjugation.
Excretion	Renal (80-90% as metabolites, <10% unchanged), biliary/fecal (minor, <5%)
Half-life	1.5-2 hours (terminal); prolonged in hepatic dysfunction or heart failure
Protein binding	65-75% (primarily to alpha-1-acid glycoprotein and albumin)
Volume of Distribution	1.1-1.6 L/kg (extensive tissue distribution, e.g., brain, heart, liver)
Bioavailability	Topical: variable, ~3-10% systemically absorbed depending on site and condition; systemic routes not applicable
Onset of Action	Topical: 3-5 minutes for local anesthesia
Duration of Action	Topical: 30-60 minutes; prolonged with epinephrine or in inflamed tissue

Classification & Brands

Dosing & administration

Apply up to 3 patches topically once daily for up to 12 hours per day. Maximum 3 patches (210 mg lidocaine) per day.

Dosage form	PATCH
Renal impairment	No dose adjustment required for GFR ≥30 mL/min. For GFR <30 mL/min, use with caution and monitor for lidocaine toxicity due to reduced clearance.
Liver impairment	Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose (e.g., apply 1-2 patches, maximum 12 hours). Child-Pugh C: Contraindicated or use with extreme caution, consider alternative therapy.
Pediatric use	Not recommended for use in pediatric patients (safety and efficacy not established). For off-label use in children ≥2 years, apply 1 patch (5% lidocaine) for 12 hours, maximum 3 patches. Weight-based not applicable.
Geriatric use	No specific dose adjustment required but monitor for adverse effects due to age-related changes in skin integrity and renal function. Use lowest effective number of patches and limit to 12-hour application.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for LIDOSITE TOPICAL SYSTEM KIT (LIDOSITE TOPICAL SYSTEM KIT).

Breastfeeding	Lidocaine is excreted into breast milk in low concentrations (M/P ratio approximately 0.4). At typical topical doses, infant exposure is negligible. Caution with high-dose or prolonged use; monitor infant for sedation, hypotonia, or feeding difficulties.
Teratogenic Risk	Lidocaine crosses the placenta. First trimester: Limited human data, no increased risk of major malformations in epidemiologic studies. Second and third trimesters: Use may cause fetal bradycardia, central nervous system depression, or acidosis if high maternal serum levels occur. Avoid use during active labor due to potential neonatal respiratory depression.

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to lidocaine, amide-type anesthetics, or any component of the formulation.","Application to inflamed, infected, or traumatized skin areas."]

Clinical Precautions

Precautions

["May cause methemoglobinemia, especially in patients with glucose-6-phosphate dehydrogenase deficiency, anemia, or those taking oxidizing agents.","Use with caution in patients with severe hepatic impairment or impaired cardiovascular function.","Do not apply to open wounds, broken skin, or mucous membranes.","Avoid contact with eyes.","Potential for systemic toxicity if applied to large areas, over prolonged periods, or with compromised circulation."]

Clinical Tips & Counseling

Drug interactions

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LIDOSITE TOPICAL SYSTEM KIT

Clinical safety rating: caution

Comprehensive clinical and safety monograph for LIDOSITE TOPICAL SYSTEM KIT (LIDOSITE TOPICAL SYSTEM KIT).

How it works

Lidocaine is an amide-type local anesthetic that stabilizes neuronal membranes by blocking voltage-gated sodium channels, thereby inhibiting the initiation and conduction of nerve impulses.

What the body does with it

Metabolism	Lidocaine is primarily metabolized in the liver via oxidative N-dealkylation by CYP1A2 and CYP3A4 to monoethylglycinexylidide (MEGX) and glycinexylidide (GX), both active metabolites. Further metabolism involves hydrolysis and conjugation.
Excretion	Renal (80-90% as metabolites, <10% unchanged), biliary/fecal (minor, <5%)
Half-life	1.5-2 hours (terminal); prolonged in hepatic dysfunction or heart failure
Protein binding	65-75% (primarily to alpha-1-acid glycoprotein and albumin)
Volume of Distribution	1.1-1.6 L/kg (extensive tissue distribution, e.g., brain, heart, liver)
Bioavailability	Topical: variable, ~3-10% systemically absorbed depending on site and condition; systemic routes not applicable
Onset of Action	Topical: 3-5 minutes for local anesthesia
Duration of Action	Topical: 30-60 minutes; prolonged with epinephrine or in inflamed tissue

Classification & Brands

Dosing & administration

Apply up to 3 patches topically once daily for up to 12 hours per day. Maximum 3 patches (210 mg lidocaine) per day.

Dosage form	PATCH
Renal impairment	No dose adjustment required for GFR ≥30 mL/min. For GFR <30 mL/min, use with caution and monitor for lidocaine toxicity due to reduced clearance.
Liver impairment	Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose (e.g., apply 1-2 patches, maximum 12 hours). Child-Pugh C: Contraindicated or use with extreme caution, consider alternative therapy.
Pediatric use	Not recommended for use in pediatric patients (safety and efficacy not established). For off-label use in children ≥2 years, apply 1 patch (5% lidocaine) for 12 hours, maximum 3 patches. Weight-based not applicable.
Geriatric use	No specific dose adjustment required but monitor for adverse effects due to age-related changes in skin integrity and renal function. Use lowest effective number of patches and limit to 12-hour application.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for LIDOSITE TOPICAL SYSTEM KIT (LIDOSITE TOPICAL SYSTEM KIT).

Breastfeeding	Lidocaine is excreted into breast milk in low concentrations (M/P ratio approximately 0.4). At typical topical doses, infant exposure is negligible. Caution with high-dose or prolonged use; monitor infant for sedation, hypotonia, or feeding difficulties.
Teratogenic Risk	Lidocaine crosses the placenta. First trimester: Limited human data, no increased risk of major malformations in epidemiologic studies. Second and third trimesters: Use may cause fetal bradycardia, central nervous system depression, or acidosis if high maternal serum levels occur. Avoid use during active labor due to potential neonatal respiratory depression.

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to lidocaine, amide-type anesthetics, or any component of the formulation.","Application to inflamed, infected, or traumatized skin areas."]