Benzocaine 20% | Lidocaine 10% | Tetracaine 10%

Applied topically to intact skin at the intended procedure site by a trained clinical staff member. This preparation is intended for in-office use only under direct medical supervision:

• Apply a uniform layer (approximately 1–2 mm thick) to the treatment area using a gloved applicator or gloved hand.
• Leave in place for 20–45 minutes (or as directed by the prescriber) to allow adequate absorption; cover with plastic wrap occlusion only if directed, as occlusion significantly increases absorption and systemic risk.
• Remove the cream completely before beginning any procedure.
• Avoid application to mucous membranes, open wounds, broken skin, or the periorbital area (risk of corneal abrasion from particulate content).
• Apply corneal shields before any periorbital procedure; BLT has been associated with corneal abrasion when gritty particulate formulations contact the eye.
• Wash hands immediately after application and removal.

Dosing (amount applied, area, and duration of application) is prescriber-determined and must account for total local anesthetic load relative to patient weight, skin integrity, and application area. Key safety parameters:

• Apply the minimum effective amount to the minimum required skin surface area; large-area application significantly increases systemic absorption risk.
• Do not use under prolonged occlusion unless specifically directed; occlusion dramatically increases systemic drug delivery.
• BLT 20/10/10 concentrations are substantially higher than most FDA-approved topical anesthetic formulations; the FDA has issued safety communications regarding compounded topical anesthetics and risk of serious adverse events, including death.
• Do not apply to mucous membranes, broken skin, or areas near the eyes.
• Onset of topical anesthesia: approximately 20–30 minutes after application; onset may vary by skin thickness and condition.

• Benzocaine: Penetrates into superficial sensory nerve endings and blocks voltage-gated sodium channels (Nav) in a non-selective, reversible manner, preventing membrane depolarization and the generation of pain action potentials. As an ester, it is metabolized locally by plasma pseudocholinesterases and skin esterases, producing PABA, which is the principal sensitizing metabolite.
• Lidocaine: Penetrates deeper tissue layers than benzocaine; as an amide, it is metabolized systemically by hepatic CYP3A4 after absorption. It binds the inner vestibule of voltage-gated sodium channels (particularly Nav1.7 and Nav1.8) in a use-dependent manner, stabilizing the inactivated state and preventing recovery of channel conductance.
• Tetracaine: Highly lipophilic ester anesthetic with slow onset but prolonged sodium channel blockade; because of its high lipid solubility it penetrates deeper into the dermis compared to benzocaine, producing longer-lasting and deeper anesthesia. Metabolized locally by plasma cholinesterases.

Compounded BLT topical anesthetic is used for prescriber-directed procedural anesthesia in:

• Dermal filler (hyaluronic acid) injection procedures
• Botulinum toxin injection procedures
• Laser skin resurfacing or laser hair removal
• Microneedling or radiofrequency microneedling (e.g., Morpheus8)
• Minor skin biopsies, shave excisions, or dermatologic procedures
• Other cosmetic and minor surgical procedures requiring superficial topical anesthesia

Prescriber clinical considerations:

• The combined concentration of active anesthetics in this formulation (20% + 10% + 10% = 40% total anesthetic) substantially exceeds concentrations in FDA-approved topical anesthetics (e.g., EMLA 2.5% lidocaine/2.5% prilocaine); systemic toxicity risk is proportionally higher.
• The FDA issued a 2006 safety communication regarding compounded topical anesthetics and deaths associated with excessive application, especially under occlusion.
• Prescribers are responsible for patient-specific dosing instructions specifying application area, amount, and duration; standard "protocols" applied broadly may not account for individual patient risk factors.
• Methemoglobinemia is a risk with benzocaine-containing preparations; caution in G6PD deficiency, infants, and patients using concurrent oxidizing drugs.
• Risk of serious corneal abrasion if gritty BLT formulation contacts the eyes during periorbital procedures.

Contraindications:

• Hypersensitivity to benzocaine, lidocaine, tetracaine, or any ester or amide local anesthetic.
• Known para-aminobenzoic acid (PABA) allergy (benzocaine metabolite).
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency or congenital methemoglobin reductase deficiency (risk of methemoglobinemia with benzocaine).
• Application to broken, abraded, infected skin or mucous membranes.
• Infants under 2 years — benzocaine is not recommended due to methemoglobinemia risk.

Warnings & Precautions:

• Systemic toxicity: Local anesthetic systemic toxicity (LAST) — manifesting as CNS excitation progressing to seizure, cardiovascular depression — is possible with excessive application area, prolonged application, or occlusive dressing; have emergency resuscitation equipment available in the procedure area.
• Methemoglobinemia: Benzocaine oxidizes hemoglobin iron from ferrous to ferric, forming methemoglobin; symptoms include cyanosis, dyspnea, and altered mental status. Highest risk in G6PD deficiency, anemia, and concurrent oxidizing drug use.
• Corneal toxicity: Gritty BLT formulations have caused corneal abrasions when particles contact the eye; use corneal shields during periorbital procedures.
• Avoid large-area, prolonged, or occluded application.

Drug Interactions:

• Class I antiarrhythmics (mexiletine, tocainide): additive sodium channel blockade risk with lidocaine if significant systemic absorption occurs.
• Oxidizing agents (nitrates, dapsone, sulfonamides): increased methemoglobin risk with benzocaine.
• Pseudocholinesterase inhibitors: may prolong ester anesthetic (benzocaine, tetracaine) metabolic clearance.

Common Side Effects: Blanching, pallor, and mild edema at the application site (expected pharmacologic vasoconstriction); erythema after removal; rare allergic contact dermatitis (ester allergy, particularly benzocaine).

Store at controlled room temperature (15–25°C / 59–77°F) in a tightly sealed, original container. Protect from heat, light, and moisture. Do not freeze — freezing may alter cream consistency. Keep out of reach of children. Use by the beyond-use date (BUD) per USP <795> compounding standards. Discard unused portions appropriately; do not reuse opened containers beyond the BUD.

Is this cream FDA-approved?

No. Compounded BLT topical anesthetic is a patient-specific, prescriber-directed 503A compounded preparation from Genesis Compounding. While individual ingredients (benzocaine, lidocaine, tetracaine) have FDA-approved formulations for various indications, this specific high-concentration three-ingredient combination is not FDA-approved. The FDA has issued safety communications regarding compounded high-concentration topical anesthetic preparations.

Why are three anesthetics combined instead of one?

Each agent has a different onset and duration profile. Benzocaine provides rapid onset of superficial anesthesia; lidocaine offers intermediate penetration and duration with broad safety data; tetracaine contributes deep penetration and prolonged duration. The combination provides faster onset and longer-lasting, more complete anesthesia than any single agent at comparable concentrations.

How long before the procedure should this be applied?

Typically 20–45 minutes prior to the procedure, per the prescriber's protocol and the specific procedure requirements. Application time and area will be specified by the clinician performing the procedure.

Is there a risk of methemoglobinemia?

Yes. Benzocaine can oxidize hemoglobin to methemoglobin, causing cyanosis and respiratory symptoms in susceptible patients — particularly those with G6PD deficiency, anemia, or concurrent use of oxidizing drugs. The prescribing clinician should screen for these risk factors before use.

Why is this kept away from the eye area?

Tetracaine and benzocaine are potent corneal anesthetics; gritty particles from incompletely dissolved components can cause corneal abrasion. Even smooth formulations pose ocular chemical irritation risk. Corneal shields should be used during any periorbital procedure, and the cream must not be allowed near the eyes.