From the Guidelines
Topical lidocaine should not be administered subcutaneously. The guidelines for the use of local anesthesia in office-based dermatologic surgery, as outlined in the Journal of the American Academy of Dermatology in 2016 1, emphasize the importance of using sterile and appropriately formulated injectable lidocaine preparations for subcutaneous administration. Key points to consider include:
- The maximum safe dose of local infiltrated anesthesia is unknown, but guidelines suggest no more than 4.5 mg/kg of lidocaine and 7.0 mg/kg of lidocaine with epinephrine should be administered in a single treatment for adults.
- Topical lidocaine formulations are specifically designed for external application to the skin or mucous membranes and are not suitable for injection due to the presence of preservatives, stabilizers, and other ingredients that could cause tissue damage.
- Injectable lidocaine preparations, typically lidocaine hydrochloride 1% or 2%, are sterile and free from additives that could cause tissue damage if injected, making them the preferred choice for subcutaneous administration.
- The concentration of lidocaine in topical products is often different from injectable forms, which could lead to dosing errors and potential toxicity if administered subcutaneously. Some important considerations for the use of local infiltrative anesthesia include:
- Infiltrative anesthesia may be combined with other forms of local anesthesia for larger or more complex cutaneous procedures.
- For children, no more than 1.5-2.0 mg/kg of lidocaine and 3.0-4.5 mg/kg of lidocaine with epinephrine should be administered in a single treatment.
- Alternate forms of local infiltration anesthesia, such as ester-type local anesthetics, bacteriostatic normal saline, or 1% diphenhydramine, may be used for patients with true allergy to lidocaine, as suggested by the guidelines 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Administration of Topical Lidocaine
- Topical lidocaine is commonly used for various pain conditions, including post-herpetic neuralgia, postsurgical pain, diabetic peripheral neuropathy, carpal tunnel syndrome, chronic lower back pain, and osteoarthritis 2.
- The formulation of topical lidocaine, such as patches or gels, can affect its absorption and efficacy 3, 4.
- Studies have shown that topical lidocaine can be effective in reducing pain perception, with minimal risk of toxicity or drug-drug interactions 4, 5.
Subcutaneous Administration
- There is no direct evidence in the provided studies to support the subcutaneous administration of topical lidocaine.
- However, a study on local anesthetics, including lidocaine, found that they can cause vasodilatation, but no type 1 allergy was observed when administered intracutaneously 6.
- It is essential to note that topical lidocaine is designed for topical use, and its safety and efficacy for subcutaneous administration are not well-established in the provided evidence.
Safety and Efficacy
- Topical lidocaine is generally considered safe, with minimal risk of systemic adverse effects 2, 4.
- However, individual patients may have unpredictably high absorption levels, and adverse reactions can occur 3.
- Clinicians should consider topical lidocaine as part of their multimodal treatments of acute and chronic pain, but it is crucial to use it under the supervision of a healthcare professional to avoid adverse toxic effects 3, 4.