Benzocaine 20% | Lidocaine 8% | Tetracaine 4%

Route: Topical application to intact skin prior to procedures requiring deeper or more prolonged anesthesia (e.g., ablative laser procedures, deeper injections, extensive vascular access).

• Apply a uniform layer to the target area; occlude per prescriber protocol for 20–45 minutes prior to procedure.
• Remove excess before initiating the procedure; the higher lidocaine concentration requires strict attention to application area size to prevent systemic toxicity.
• Avoid application to large surface areas simultaneously. Prescriber supervision during application is advisable for extensive procedures.

Dosing is entirely prescriber-determined. The higher lidocaine concentration (8% vs. 6%) provides enhanced depth but also increases the systemic absorption potential:

• Apply the minimum effective quantity; restrict to the target area.
• In adults, total application area should be assessed relative to body weight and surface area to stay within safe lidocaine dose limits.
• Not intended for injection. Final dosing is established by the prescriber based on procedure, patient weight, and clinical status.

• Benzocaine: Ester local anesthetic; blocks sodium channel conductance at the nerve membrane, preventing action potential propagation; rapid onset from high unionized fraction at physiological pH.
• Lidocaine (8%): Amide local anesthetic; higher concentration enhances depth of penetration and sodium channel occupancy; use-dependent blockade ensures selective action on actively firing nociceptive fibers.
• Tetracaine: Highly lipid-soluble ester local anesthetic; deep membrane penetration produces longer-lasting sodium channel blockade, extending the anesthetic duration of the combination.

This higher-lidocaine formulation is typically indicated when procedures require greater depth of anesthesia or longer duration than standard BLT 20/6/4% provides. Clinical applications include ablative fractional laser resurfacing, more invasive facial injection procedures, or use in patients with reduced anesthetic sensitivity.

Prescriber monitoring considerations:

• The elevated lidocaine concentration (8%) requires careful attention to total dose, particularly in patients with low body weight, hepatic impairment, or compromised skin barrier.
• Monitor for methemoglobinemia signs (cyanosis, dyspnea) given benzocaine content; assess G6PD status if applicable.
• Monitor for systemic local anesthetic toxicity signs: perioral numbness, metallic taste, tinnitus, cardiovascular changes.

Contraindications:

• Known hypersensitivity to any ingredient or PABA (for ester components)
• Application to large, denuded, or highly vascular surface areas
• Patients with documented methemoglobinemia or significant G6PD deficiency requiring extreme caution

Warnings & Precautions:

• Methemoglobinemia: Benzocaine carries a risk of methemoglobinemia; the higher combined anesthetic load warrants strict dose and area limits.
• LAST (Local Anesthetic Systemic Toxicity): At 8% lidocaine, systemic absorption over large areas may approach toxic thresholds more rapidly; have resuscitative equipment available for major procedural use.
• Hepatic impairment: Lidocaine is extensively hepatically metabolized; use caution in significant hepatic impairment.
• Cholinesterase deficiency may prolong ester anesthetic (benzocaine, tetracaine) activity.

Drug Interactions:

• Concurrent oxidant drugs (dapsone, nitrates, sulfonamides) may potentiate methemoglobinemia with benzocaine.
• Propranolol increases systemic lidocaine concentrations.
• Concomitant systemic local anesthetics or antiarrhythmics increase toxicity risk.

Common Side Effects: Local erythema, transient blanching, burning or stinging, pruritus, contact dermatitis; with excessive dosing: dizziness, circumoral paresthesia, tinnitus, nausea.

Store at controlled room temperature (20–25°C / 68–77°F). Protect from heat, freezing, and light. Do not use after the beyond-use date assigned by Genesis Compounding. Keep out of reach of children and store away from food.

How does the 8% lidocaine formulation differ from the 6% formulation?

The higher lidocaine concentration (8%) is intended to provide greater depth and duration of skin anesthesia, making it appropriate for procedures requiring deeper tissue coverage or longer contact time. This formulation requires careful attention to application area size to avoid systemic toxicity.

How should this cream be applied?

Apply a uniform thin layer to the target area and cover with an occlusive dressing for the duration prescribed (typically 20–45 minutes). Remove all cream before beginning the procedure. Apply only to the specified area—do not treat large body surface areas simultaneously.

What signs indicate systemic absorption is occurring?

Early signs of local anesthetic systemic toxicity include metallic taste, circumoral numbness, dizziness, ringing in the ears, and visual disturbances. These symptoms require immediate removal of the cream and medical evaluation.

Is this an FDA-approved product?

This is a 503A compounded preparation prepared by Genesis Compounding for a specific patient based on a valid prescriber order. It is not an FDA-approved drug product, but each active ingredient is a well-characterized, established local anesthetic.

Can this be used on broken or infected skin?

No. This formulation should not be applied to broken, open, or infected skin, as compromised barrier function greatly increases systemic absorption and the risk of toxicity.