What are the consequences of not having a 12-hour interval without a lidocaine (lidocaine) patch, and can it be applied after using lidocaine (lidocaine) cream?

From the Guidelines

I strongly recommend adhering to the 12-hour on, 12-hour off schedule for lidocaine patches as directed to minimize the risk of adverse reactions and ensure optimal pain management. Using the patch continuously without the 12-hour break could increase your risk of side effects such as skin irritation, redness, or potentially systemic absorption of lidocaine leading to more serious adverse reactions like irregular heartbeat, seizures, or breathing problems, as supported by the study on lidocaine pharmacokinetics 1.

Regarding applying a patch after using lidocaine cream, it's generally not recommended to use multiple forms of lidocaine simultaneously as this could lead to excessive lidocaine absorption and toxicity. If the cream isn't providing adequate relief after an hour, contact your healthcare provider before adding the patch. The 12-hour off period is specifically designed to allow your skin to recover and prevent lidocaine buildup in your system, as noted in the standards of care in diabetes-2024 1.

Some key points to consider:

• Lidocaine patches have limited data supporting their use in certain conditions, but they may be effective for localized pain management 1.
• The patches work by blocking sodium ion channels required for the initiation and conduction of neuronal impulses, resulting in local anesthesia after topical application 1.
• It is crucial to follow the recommended usage schedule to avoid potential adverse reactions, and if your current pain management approach isn't effective, discuss alternative options with your healthcare provider rather than modifying the recommended usage schedule.

In terms of the consequences of not following the 12-hour on, 12-hour off schedule, the risk of systemic absorption of lidocaine and subsequent adverse reactions increases, highlighting the importance of adhering to the recommended usage schedule 1. Additionally, using multiple forms of lidocaine simultaneously can lead to excessive lidocaine absorption and toxicity, emphasizing the need for caution when using these products 1.

From the FDA Drug Label

Warnings For external use only Do not use ◆ on large areas of the body or on cut, irritated or swollen skin ◆ on puncture wounds ◆ for more than one week without consulting a doctor When using this product ◆ use only as directed Read and follow all directions and warnings on this carton ◆ rare cases of serious burns have been reported with products of this type ◆ do not bandage or apply local heat (such as heating pads) to the area of use with a medicated patch ◆ avoid contact with eyes and mucous membranes ◆ a transient burning sensation may occur upon application but generally disappears in several days Discontinue use and consult a doctor if ◆ condition worsens ◆ redness is present ◆ irritation develops ◆ symptoms persist for more than 7 days or clear up and occur again within a few days ◆ you experience signs of skin injury, such as pain, swelling, or blistering where the product was applied

The FDA drug label does not answer the question.

From the Research

Lidocaine Patch Usage and Adverse Reactions

• The directions for using a lidocaine patch specify a 12-hour on and 12-hour off cycle 2.
• There is no clear evidence on the consequences of not having the patch off for a full 12 hours, but it is essential to follow the recommended usage to minimize potential adverse reactions.
• Adverse reactions to lidocaine patches are generally mild and may include skin irritation, redness, or itching 3, 4.

Using Lidocaine Patch after Lidocaine Cream

• There is no specific study that addresses the use of a lidocaine patch after applying lidocaine cream 2, 3, 4.
• However, it is crucial to follow the recommended usage and dosage of both the cream and the patch to avoid excessive lidocaine absorption and potential adverse reactions.
• Clinicians must use their clinical reasoning and expertise to make informed decisions about the best course of treatment for individual patients, considering the available evidence and the patient's specific needs 5.

Potential Interactions and Precautions

• Lidocaine patches and creams can interact with other medications, such as certain antidepressants, and may exacerbate underlying medical conditions, like heart problems 3, 4.
• Patients should inform their healthcare provider about any medications they are taking or any medical conditions they have before using a lidocaine patch or cream.
• It is essential to monitor patients for potential adverse reactions and adjust the treatment plan as needed 2, 4.