Topical anesthetics are made of different APIs that are highly effective in blocking pain. The strongest topical anesthetic contains 4% lidocaine, a skin penetrating agent (API). An API must be able to penetrate the skin to achieve an effect. Some topical anesthetics contain other components, such as skin permeation enhancers and soothing agents. Before you buy topical numbing cream, this information will help you make an informed decision.
A topical anesthetic containing 4% lidocaine has the highest level of local anesthesia. It is used to numb the skin for procedures such as cosmetic surgery. This topical anesthetic is most effective when applied to a small area. However, it should be used with caution, especially in children.
Although lidocaine is generally safe, repeated use of the cream may result in methemoglobinemia, a serious blood problem in which red blood cells cannot carry enough oxygen to the body. People with low G6PD levels are at greater risk. In addition, lidocaine can cause the skin to turn blue when exposed to hydrogen peroxide.
Topical anesthetics work by inhibiting voltage-gated sodium channels in the membrane of neuronal cells. This leads to reduced pain perception and reduced muscle contraction. These agents have three basic components, which are known as lipophilic, aromatic, and lipophilic. The lipophilic ring is important because it increases their solubility in lipids, which correlates with their potency.
Prilocaine is one of the most popular topical anesthetics and is used as a local anesthetic alone or in combination with other topical anesthetics. It is an amide, unlike lidocaine and mepivacaine, and is available in two formulations: 4% prilocaine alone and 4% prilocaine with epinephrine. Both formulations are safe for use in pregnancy.
Topical anesthetics are much safer than injections and can be applied to specific areas without using needles. However, practitioners should be aware of potential side effects and the potential for allergic reactions in patients with neuropathies or hypersensitivities.
EMLA is an oil-based cream with a mixture of lidocaine and prilocaine. It is usually applied directly onto the skin under an occlusive dressing. Its adverse effects are generally localized and non-lethal, but serious reactions include methemoglobinemia, central nervous system toxicity, and cardiotoxicity. It takes approximately 50 minutes for the maximum effect to be felt.