Dosing for 23% Lidocaine and 7% Tetracaine Cream
Apply the 23% lidocaine/7% tetracaine cream to the treatment area for 30-60 minutes under occlusion, using no more than 1.5-2 grams per application to avoid systemic toxicity, with particular caution in children, patients with larger surface areas, males, and non-white individuals who demonstrate higher serum absorption.
Application Guidelines
Standard Dosing Protocol
- Application time: 30-60 minutes under occlusion before the procedure 1
- Maximum amount: Limit to 1.5-2 grams per application to minimize systemic absorption
- Surface area: Restrict application to the smallest effective treatment area
Critical Safety Considerations
Monitor for systemic toxicity risk factors - Research demonstrates that facial application of 23% lidocaine/7% tetracaine produces median peak serum levels of 1.15 μg/mL, with individual peaks reaching 3.4 μg/mL 1. While these levels remain below the toxic threshold (typically >5 μg/mL), certain patient characteristics significantly increase absorption:
- Male sex: Associated with significantly higher serum lidocaine levels (p < 0.01) 1
- Non-white ethnicity: Linked to elevated absorption (p = 0.02) 1
- Larger facial surface area: Correlates with increased systemic levels (p = 0.04) 1
Maximum Safe Lidocaine Doses (All Formulations Combined)
When using this high-concentration topical formulation, you must account for total lidocaine exposure:
Adults:
Children:
- Maximum 1.5-2.0 mg/kg lidocaine without epinephrine 2
- Maximum 3.0-4.5 mg/kg lidocaine with epinephrine 2
Practical Calculation Example
For a 70 kg adult using 23% lidocaine/7% tetracaine cream:
- 2 grams of cream contains 460 mg of lidocaine
- Maximum safe dose = 315 mg (4.5 mg/kg × 70 kg)
- This exceeds safe limits - therefore use ≤1.4 grams maximum
Common Pitfalls to Avoid
Skin irritation and hyperpigmentation: Compounded 23% lidocaine/7% tetracaine commonly causes irritant contact dermatitis, which can result in persistent hyperpigmentation, particularly in darker-skinned patients 1. Warn patients preemptively and consider patch testing in high-risk individuals.
Combining with infiltrative anesthesia: If supplemental infiltration is needed, carefully calculate cumulative lidocaine dose from both topical and injected sources to stay within maximum safe limits 2.
Unsupervised use: This high-concentration compounded formulation should only be used under direct physician supervision due to systemic toxicity risk 1.
Alternative Considerations
Standard FDA-approved topical lidocaine products contain only 4% lidocaine 3 and are applied 3-4 times daily for pain relief - these are fundamentally different products with different safety profiles than the 23%/7% compounded formulation used for procedural anesthesia.
For painful dermatologic laser procedures, lidocaine/prilocaine cream (EMLA) under plastic occlusion may provide superior pain control with a better-established safety profile compared to lidocaine/tetracaine formulations 4.