From the Guidelines
Lidocaine viscous 2% is recommended as a topical anesthetic preparation for relieving pain in the mouth, with a suggested dosage of 15 mL per application, as an alternative to other treatments. This recommendation is based on the UK guidelines for the management of Stevens-Johnson syndrome/toxic epidermal necrolysis in adults 2016, published in the British Journal of Dermatology 1. The guidelines suggest that a topical anesthetic preparation, such as viscous lidocaine 2%, may be used to relieve oral discomfort.
Some key points to consider when using lidocaine viscous include:
- The standard concentration is 2% lidocaine in a thick, syrupy solution that adheres to tissues
- Adults typically use 5-15 mL swished in the mouth for 1-2 minutes and then spit out, up to 4 times daily
- The medication works by temporarily blocking nerve signals in the treated area, providing pain relief for approximately 30-60 minutes
- Side effects may include numbness that affects swallowing, allergic reactions, or systemic absorption if too much is swallowed
- Patients should avoid eating or drinking for 60 minutes after use to prevent injury from accidental biting of numbed areas
It is essential to follow the prescribed dosage and frequency of use to minimize the risk of toxicity, especially in vulnerable populations such as children, elderly patients, or those with liver disease, as noted in the guidelines 1. Additionally, other treatments, such as antiseptic oral rinses and topical corticosteroids, may be used in conjunction with lidocaine viscous to manage oral discomfort and promote healing 1.
From the FDA Drug Label
Use temporarily relieves minor pain The FDA drug label does not answer the question.
From the Research
Lidocaine Viscous Overview
- Lidocaine viscous is a topical anesthetic used for various pain conditions, including post-herpetic neuralgia, postsurgical pain, diabetic peripheral neuropathy, carpal tunnel syndrome, chronic lower back pain, and osteoarthritis 2.
- It has limited absorption and a relative lack of systemic adverse events, making it an attractive analgesic option for vulnerable patients 2.
Efficacy and Safety
- Topical lidocaine has been shown to be effective in reducing pain in various conditions, with some degree of evidence supporting its use in postsurgical pain, diabetic peripheral neuropathy, carpal tunnel syndrome, chronic lower back pain, and osteoarthritis 2.
- However, its efficacy in reducing pain during inferior alveolar nerve block in schoolchildren was found to be similar to that of benzocaine and EMLA cream, with no statistically significant difference between the groups 3.
- Lidocaine and benzocaine were found to be equally efficient in reducing pain caused by insertion of needles into the palate, and both were better than placebo 4.
Methemoglobinemia Risk
- Topical anesthesia with lidocaine or benzocaine can occasionally cause methemoglobinemia, a rare but potentially fatal disorder where the blood has a reduced ability to transport oxygen 5, 6.
- Benzocaine was found to be more likely to cause methemoglobinemia than lidocaine, with its hydroxylamine metabolite being more active in forming methemoglobin than the potentially methemoglobin-forming metabolites of lidocaine 5.
- A case report described a rapid onset of methemoglobinemia associated with local anesthetic use, including lidocaine and benzocaine sprays, highlighting the importance of early diagnosis and timely treatment 6.