What are the guidelines for using lidocaine (local anesthetic) patches in children?

Lidocaine Patches in Pediatric Patients

Lidocaine patches can be used in children 2 years and older for topical pain relief, applied up to 3-4 times daily, but practitioners must calculate maximum safe dosing (4.4 mg/kg without epinephrine) before application to avoid systemic toxicity, particularly when combined with other local anesthetics or sedatives. 1, 2

Age-Specific Recommendations

• Children ≥2 years: FDA-approved for topical application to affected areas up to 3-4 times daily 1
• Children <2 years: Physician consultation required before use 1
• Infants <6 months: All amide local anesthetic doses (including topical lidocaine) must be reduced by 30% due to delayed metabolism and decreased plasma protein binding 2, 3

Critical Dosing Calculations

Before applying lidocaine patches, calculate the maximum allowable safe dosage to prevent cumulative toxicity:

• Maximum lidocaine dose without epinephrine: 4.4 mg/kg 2
• Maximum lidocaine dose with epinephrine: 7.0 mg/kg 2
• Each 5% lidocaine patch contains 700 mg of lidocaine, though systemic absorption is typically minimal 4
• For a 13 kg child: Maximum safe dose is 57.2 mg without epinephrine or 91 mg with epinephrine 3

Safety Considerations and Monitoring

Avoid excessive topical application to mucosal surfaces where systemic uptake dramatically increases, potentially causing seizures or methemoglobinemia: 2

• Remain within manufacturer's recommendations regarding allowable surface area application 2
• Enhanced sedative effects occur when highest recommended doses are combined with other sedatives or opioids 2, 3
• When using high doses or multiple local anesthetic sources, document vital signs at least every 5 minutes initially 2, 3
• Calculate total lidocaine exposure from all sources (patches, infiltration, topical) to avoid exceeding maximum safe dose 3, 5

Evidence for Efficacy in Pediatrics

The evidence for lidocaine patches in children is limited but suggests moderate efficacy with excellent safety profile:

• A prospective multicenter study in 6-21 year-olds showed 48.6% achieved clinically significant pain relief (≥2 point VAS decrease) for neuropathic pain and sickle cell vaso-occlusive crises 6
• Only 7.7% experienced mild (grade 1-2) toxicities in this pediatric study 6
• Plasma lidocaine levels remained well below toxic thresholds (<10 ng/mL) even with continuous application 7
• Continuous 72-hour application in adults produced plasma concentrations (186-225 ng/mL) well below antiarrhythmic or toxic levels (typically >5000 ng/mL) 4

Common Pitfalls to Avoid

• Failing to calculate maximum allowable dose before application, particularly when patches are used with other local anesthetic interventions 3
• Not accounting for reduced clearance in infants <6 months, who require 30% dose reduction 2, 3
• Applying to highly vascular or mucosal surfaces where systemic absorption increases dramatically 2
• Combining with other sedatives or local anesthetics without considering additive effects and cumulative dosing 2, 3
• Using in children <40 kg when also administering IV lidocaine infusions, as this combination should be avoided 3

Recognition and Treatment of Toxicity

Early signs of local anesthetic systemic toxicity include CNS excitation or depression and cardiac depression: 2, 3

• Seizures are often the first manifestation 2
• Cardiac depression and dysrhythmias may follow 8
• Treatment protocol: Immediate ventilation with 100% oxygen, benzodiazepines for seizures (midazolam 0.1-0.2 mg/kg IV), and 20% lipid emulsion (1.5 mL/kg bolus) for cardiovascular collapse 2
• Alert nearest facility with cardiopulmonary bypass capability 2