What is the proper administration method for benzocaine (local anesthetic)/menthol (methyl salicylate)?

From the Guidelines

Benzocaine/menthol products should be applied topically to the affected area, but their use is not recommended for acute otitis externa (AOE) as they may mask progression of underlying disease while pain is being suppressed, as stated in the clinical practice guideline for AOE 1. When using benzocaine/menthol products, it is essential to follow the instructions on the product packaging, typically applying a thin layer to the affected area or using oral products like lozenges or throat sprays as directed.

• Key considerations for use include:
  • Applying a thin layer to the affected area
  • Allowing oral products to dissolve slowly in the mouth without chewing
  • Using the product every 2-4 hours as needed for pain relief, but not exceeding the maximum daily dosage
  • Ensuring the affected area is clean and dry before application
  • Washing hands before and after application
• It is crucial to note that benzocaine/menthol products work through different mechanisms, with benzocaine blocking nerve signals as a local anesthetic and menthol creating a cooling sensation that distracts from pain 1.
• However, the primary concern with using these products for AOE is the potential to mask the progression of the underlying disease, which could lead to delayed or inadequate treatment, as highlighted in the guideline 1.
• Therefore, it is recommended to prioritize evidence-based treatments for AOE, such as acetaminophen or nonsteroidal anti-inflammatory drugs, and reserve benzocaine/menthol products for other indications where their use is supported by clinical evidence.

From the FDA Drug Label

Warnings Allergy Alert: do not use this product if you have a history of allergy to local anesthetics such as procaine, butacaine, benzocaine or other "caine" anesthetics When using this product avoid contact with eyes do not exceed recommended dosage do not use for more than 7 days unless directed by a dentist or doctor The proper administration method for benzocaine (local anesthetic) is to avoid contact with eyes and not exceed recommended dosage. For menthol (methyl salicylate), the label does not provide administration instructions.

• Key administration instructions for benzocaine:
  • Avoid contact with eyes
  • Do not exceed recommended dosage
  • Do not use for more than 7 days unless directed by a dentist or doctor 2 No conclusion can be drawn for the proper administration of menthol (methyl salicylate) from the provided labels.

From the Research

Administration Method for Benzocaine and Menthol

• The proper administration method for benzocaine (local anesthetic) and menthol (methyl salicylate) is not explicitly stated in the provided studies.
• However, it can be inferred that benzocaine should be used with caution due to the risk of methemoglobinemia, as reported in studies 3 and 4.
• Topical application of benzocaine is commonly used, but the dosage and administration method may vary depending on the specific product and medical procedure 3, 5, 4.
• Menthol, on the other hand, is often used as a topical agent to produce a cooling effect and reduce pain, as described in study 6.
• The study 5 mentions that local anesthetics, including benzocaine, can be recommended in the first-line treatment of sore throat, but it does not provide specific guidance on the administration method.
• Study 7 discusses a colorimetric assay for benzocaine, but it does not provide information on the administration method.