Maximum doses, pediatric age tiers, pharmacokinetics, and clinical pearls
Clinical Decision Support Tool. This page is intended as a reference aid for licensed healthcare professionals. It does not replace clinical judgment. Always verify dosing against current guidelines, institutional protocols, and patient-specific factors before administration.
| Formulation | Max Dose (mg/kg) | Absolute Max (mg) |
|---|---|---|
| Lidocaine without epinephrine | 4.5 – 5 mg/kg | 300 mg |
| Lidocaine with epinephrine | 7 mg/kg | 500 mg |
Dose range convention: The lower bound (4.5 mg/kg) is the conservative default used for fractional toxicity calculations. Doses between 4.5 and 5 mg/kg trigger a soft warning. The absolute maximum (300 mg or 500 mg) applies regardless of patient weight.
Pediatric doses are derived from adult mg/kg values scaled by an age-dependent fraction reflecting hepatic enzyme maturity and volume of distribution.
| Age Tier | Age Range | Scaling | Max Dose (mg/kg) |
|---|---|---|---|
| Neonate | < 1 month | 50% | 2.25 – 2.5 mg/kg |
| Young Infant | 1 – < 6 months | 70% | 3.15 – 3.5 mg/kg |
| Older Infant | 6 – < 12 months | 75% | 3.375 – 3.75 mg/kg |
| Child | 1 – 7 years | 100% | 4.5 – 5 mg/kg |
| Adolescent | 8 – 17 years | 100% | 4.5 – 5 mg/kg |
| Age Tier | Age Range | Scaling | Max Dose (mg/kg) |
|---|---|---|---|
| Neonate | < 1 month | 50% | 3.5 mg/kg |
| Young Infant | 1 – < 6 months | 70% | 4.9 mg/kg |
| Older Infant | 6 – < 12 months | 75% | 5.25 mg/kg |
| Child | 1 – 7 years | 100% | 7 mg/kg |
| Adolescent | 8 – 17 years | 100% | 7 mg/kg |
Neonatal Warning: Neonates (<1 month) have profoundly immature hepatic metabolism. CYP1A2 activity is approximately one-third of adult levels. Use the most conservative dose and monitor closely. Neonates and young infants may present with sudden cardiovascular collapse without prodromal CNS symptoms of toxicity.
| Concentration | mg per mL |
|---|---|
| 0.5% | 5 mg/mL |
| 1% | 10 mg/mL |
| 1.5% | 15 mg/mL |
| 2% | 20 mg/mL |
Practical tip: Using the lowest effective concentration reduces the risk of systemic toxicity without compromising block quality. For field blocks and subcutaneous infiltration, 0.5% or 1% is generally sufficient.
| Parameter | Value |
|---|---|
| Elimination half-life | 1.6 hours |
| Primary metabolism | Hepatic (CYP1A2) |
| CYP1A2 maturation | Reaches adult activity at 7–8 years |
| Protein binding | ~65% (alpha-1 acid glycoprotein) |
| pKa | 7.9 |
| Onset | Rapid (2–5 minutes) |
| Duration (without epi) | 30–120 minutes (site-dependent) |
| Duration (with epi) | 60–180 minutes (site-dependent) |
| Classification | Amide local anesthetic |
Lidocaine is metabolized primarily by CYP1A2, which does not reach adult activity levels until approximately 7–8 years of age. This is the pharmacologic basis for the pediatric dose reductions in neonates and infants. Children aged 1–7 years receive full adult mg/kg doses because, despite incomplete CYP1A2 maturation, they have a larger volume of distribution relative to body weight that offsets the reduced clearance.
Epinephrine-containing local anesthetic solutions should not be injected into end-arterial territories: digits (fingers and toes), penis, ear pinna, and nose tip. Vasoconstriction in these areas risks tissue ischemia and necrosis. When epinephrine is contraindicated, use the lower (no-epinephrine) dose limits.
Tumescent lidocaine dosing uses substantially higher mg/kg limits than standard infiltration because the highly dilute subcutaneous technique results in very slow systemic absorption (peak plasma at 12–14 hours vs. 30–60 minutes for standard infiltration). See the dedicated tumescent lidocaine dosing guide for age-tiered limits and contraindications.
Lidocaine (and its metabolite o-toluidine) can cause methemoglobinemia, particularly at high doses, in neonates, or when combined with other oxidizing agents (e.g., prilocaine, dapsone, nitrates). Monitor for cyanosis unresponsive to supplemental oxygen.
The maximum dose of lidocaine without epinephrine is 4.5–5 mg/kg, with an absolute maximum of 300 mg regardless of patient weight. This applies to adults and children aged 1 year and older. Neonates and infants require age-adjusted dose reductions based on hepatic enzyme maturity.
The maximum dose of lidocaine with epinephrine is 7 mg/kg, with an absolute maximum of 500 mg. Epinephrine causes local vasoconstriction, slowing systemic absorption and effectively raising the safe dose ceiling. Epinephrine-containing solutions should not be used in end-arterial territories (digits, penis, ear, nose tip).
Lidocaine can be used safely in pediatric patients with appropriate age-adjusted dose reductions. MaxLocal uses a 5-tier pediatric system: neonates (<1 month) receive 50% of adult doses, young infants (1–6 months) 70%, older infants (6–12 months) 75%, and children 1 year and older receive full adult mg/kg doses. The key concern is CYP1A2 enzyme immaturity, which does not reach adult levels until 7–8 years of age.
Tumescent lidocaine dosing differs substantially from standard infiltration due to slow systemic absorption from dilute subcutaneous solutions. For patients 12 years and older, the maximum tumescent lidocaine dose is 28–35 mg/kg with an absolute cap of 3,500 mg (Klein 2016). Children 6 months to 11 years may receive up to 7 mg/kg (Blunt 2003). Tumescent lidocaine is contraindicated in infants under 6 months due to immature CYP1A2 metabolism.
Weight-based dosing, 5-tier pediatric age adjustments, fractional toxicity tracking, and instant LAST protocol access — all offline.
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