What is the recommended dose and strength of lidocaine (local anesthetic) injection for newborn circumcision?

Lidocaine Dosing for Newborn Circumcision

For newborn circumcision, use lidocaine 1% without epinephrine at a maximum dose of 5 mg/kg via dorsal penile nerve block (DPNB), which translates to approximately 0.5 mL per injection site (1 mL total for bilateral block) in an average 3-4 kg newborn. 1, 2

Specific Dosing Parameters

Maximum Safe Dose

• Neonates and infants: 5 mg/kg of lidocaine is the maximum safe dose 3, 1
• For a typical 3.5 kg newborn, this equals 17.5 mg total (1.75 mL of 1% lidocaine) 3
• Use 1% lidocaine concentration (10 mg/mL) for ease of dosing and safety 1

Technique-Specific Dosing

• Dorsal penile nerve block (DPNB): 0.4-0.8 mL of 1% lidocaine per side (total 0.8-1.6 mL for bilateral block) 2
• This is the most effective pharmacological intervention for circumcision pain, with proven efficacy in randomized controlled trials 2, 4
• Ring block technique uses similar volumes distributed circumferentially 2

Critical Administration Guidelines

Pain Reduction During Injection

The American Academy of Pediatrics recommends these techniques to minimize injection pain: 3

• Buffer lidocaine with sodium bicarbonate (9:1 ratio of lidocaine to bicarbonate) 3
• Warm the lidocaine solution before injection 3
• Inject slowly using a small-gauge needle (25-27 gauge) 3
• Buffered lidocaine remains stable for up to 30 days when prepared in advance 3

Epinephrine Considerations

• Epinephrine may be considered for penile procedures but is not routinely necessary for circumcision 3
• One retrospective study showed no complications with epinephrine use during penile ring block for circumcision 3
• If epinephrine is used, maximum dose increases to 7 mg/kg, but this is rarely needed in neonates 1

Multimodal Analgesia Approach

Required Adjuncts

The American Academy of Pediatrics states that nonpharmacologic techniques alone are insufficient and must be combined with anesthetic: 4

• Oral sucrose 25% solution: 2 mL (1 mL per cheek) given 2 minutes before procedure 3
• Pacifier use during and after the procedure 3, 2, 4
• Skin-to-skin contact or breastfeeding if feasible 3

Topical Anesthetics (Less Effective Alternative)

• EMLA cream (lidocaine-prilocaine) is less effective than DPNB but may be used if injection is refused 2, 4
• Apply 60-90 minutes before procedure with appropriate dosing to avoid methemoglobinemia 3, 2
• Topical anesthetics should not replace injectable anesthesia as the sole method 4

Safety Monitoring

Contraindications and Precautions

• Avoid in infants with anatomic abnormalities (hypospadias, chordee) - refer to pediatric urology 5
• Do not perform if infant is unstable or unhealthy 4
• Risk of injection-related adverse effects (bruising/hematoma) is 6.7% with DPNB 2
• No cases of systemic lidocaine toxicity have been reported in neonatal circumcision when dosed appropriately 2

Signs of Toxicity (Rare but Critical)

Early warning signs include: 1, 6

• Circumoral numbness or facial tingling
• Muscle twitching
• Altered consciousness

If toxicity suspected: immediately stop procedure, provide airway support, and prepare lipid emulsion therapy 6

Procedural Timing

• Allow 3-5 minutes after DPNB injection before beginning circumcision for adequate anesthesia onset 2
• The Mogen clamp technique is associated with shorter procedure time and less pain compared to Gomco clamp 2, 5

Postoperative Analgesia

• Acetaminophen (paracetamol) 10-15 mg/kg every 4-6 hours may be given for postoperative pain 2
• Continue comfort measures (pacifier, swaddling) in recovery period 2