Topical lidocaine 4% is used to numb the skin. It numbs the skin where it is applied to a localized surface area. Topical lidocaine 4% is the highest concentration suggested and approved by the United States Food and Drug Administration (US FDA or FDA) for use on the skin. 5% topical lidocaine creams are approved for ano-rectal use, such as for the relief of pain, burn and itch for hemorrhoids.
Any concentration above topical lidocaine 4% is designated as Rx by the US FDA. In Canada, topical lidocaine 6% is the highest for use on the skin.
This medicine contains the active ingredient lidocaine hydrochloride (previously known as lignocaine hydrochloride in the UK).
Lidocaine is a type of medicine called a local anaesthetic. It is used to numb areas that would otherwise feel pain.
Pain is caused by the stimulation of pain receptors at the ends of nerves. The stimulation causes sodium to enter the nerve ending, which causes an electrical signal to build up in the nerve. When this electrical signal is big enough, it passes along the nerve to the brain, where the signal is interpreted as pain.
Lidocaine works by temporarily blocking this pathway of pain signals along nerves. It does this by stopping the sodium entering the nerve ending at the site of the pain. This prevents an electrical signal building up and passing along the nerve fibers to the brain.
When applied locally to a surface treatment area, topical lidocaine 4% works by blocking the neuronal sensations of pain (pain signals).
In order for the active ingredient to work, it must first get past the barrier layer of the skin known as the stratum corneum. This layer is designed to block toxins and other health risk causing contaminants into the body system. It also blocks other materials from entering the body. Therefore, ingredients called skin penetration enhancers, also known as drivers, must be included for maximum efficacy of topical lidocaine 4% cream.
Some of the more commonly well-known safe and effective drivers are:
When one or a combination of two or more of these drivers are added into the cream formulation, the active ingredient has a much better chance of entering the skin. These drivers are known to temporarily alter the skin making it more permeable to the lidocaine molecule entering. Once in the skin at the level where nerves are located, the lidocaine can go to work blocking the sodium that enters the channels that signal the pain response.
NeuroMed 7 is a topical lidocaine 4% cream. Its formulation includes MSM, ethoxydiglycol and propylene glycol. It is supplied in sanitary, single-use packets to minimize the risk of cross-contamination.