Lidocaine is one of the most commonly used anesthetic ingredients in topical anesthetic creams. The onset of action of lidocaine is rapid and compared to other topical anesthetics it has an average duration of action. In general there is a low incidence of side effects when it is used correctly but there are some important contraindications. Lidocaine has been made in patches, gels, sprays, ointments, creams and more for providing pain relief and numbing for a variety of medical procedures and health conditions.

What is Lidocaine and How Does Lidocaine 10% Work?

Lidocaine 10% cream works by blocking pain signals in the nerve endings in the skin. In more accurate terms it binds to and inhibits voltage-gated sodium channels, which inhibits the ionic fluxes required for the initiation and conduction of impulses. This inhibition produces local anesthesia. Lidocaine is an amide local anesthetic – a class that also includes bupivacaine and ropivacaine. When lidocaine was introduced in 1948, it quickly became the go-to anesthetic for a variety of procedures. It is now used both as an injection and topically for numbing before procedures and for pain relief.  

While patients may report allergies to local anesthetics, in the majority of cases the reactions are not immune-mediated. In fact, only about 1% of reported allergies to local anesthetics are actually related to an immune response. Instead some patients may have hypersensitivities to ingredients in a formulation – for example the preservative methylparaben. A true sensitivity may be discovered through a test but usually this is outside the scope of what is done in a practice.

A 10% lidocaine numbing cream may be used before skin procedures like laser treatments, injections, microneedling, and more. While some may want to use this high-strength cream for getting a tattoo or daily pain relief, it is important to remember that this product is available by prescription only. In most cases it should only be used under the supervision of a trained healthcare provider.

Lidocaine Toxicity and Precautions

Although an allergic reaction is rare, lidocaine can cause adverse events when serum concentrations become excessively high. The toxic serum concentration of lidocaine is 5ug/mL. It would be difficult to reach this serum concentration under normal use of topical lidocaine. However incorrect use, including the use of extended application times and occlusion, can raise serum concentrations significantly.

Clinical symptoms of lidocaine toxicity include lightheadedness, “pins and needles” sensation, nausea, and vomiting, which can progress to seizures, arrhythmias, and cardiorespiratory depression. All anesthetics have the ability to cause toxicity. That is why it is important for numbing creams to be used only as prescribed or be applied by a trained healthcare provider. A technique called occlusion, where the cream is applied and then covered with plastic, has resulted in many of the severe adverse reactions associated with topical lidocaine when it is done by individuals at home. Read this article for more tips on using compounded numbing creams.

Some studies have shown that over-the-counter products result in higher serum concentrations of lidocaine compared to prescription compounded products with lidocaine. There are also significant differences between individuals when it comes to absorption of lidocaine and reactions to high serum concentrations. Each individual’s skin can absorb topically applied drugs differently based on the patient’s unique physiology. A patient with broken skin may also absorb more of the anesthetic ingredients. Since lidocaine is metabolized in the liver and excreted by the kidneys, patients with liver or kidney problems may also have different reactions to elevated serum levels.

Availability of 10% Lidocaine Cream

Commercially available lidocaine creams that are sold over-the-counter generally are made in strengths between 2-5%. A compounding pharmacy can make creams with higher percentages including a 10% lidocaine cream. These higher-strength numbing creams are available only with a prescription. The higher strength numbing creams provide a more potent anesthesia that can improve the patient experience, especially for skin and cosmetic procedures performed in dermatology offices.

Over the counter numbing creams that contain lidocaine are numerous and widely available in stores and online. They have varying degrees of quality and should be used with caution. While it is true that compounded topical anesthetics are not FDA approved, over-the-counter numbing creams are not FDA approved either. Because lidocaine cream is allowed as an OTC, many manufacturers market these types of formulations without much oversight of their manufacturing processes. A compounding pharmacy is heavily regulated and uses pharmaceutical precision to make topical anesthetics that meet the doctor’s exact specifications and use only the highest quality ingredients.

Compounded topical anesthetics like lidocaine 10% cream and BLT cream should in the majority of cases be administered under the supervision of a healthcare provider. Because of the higher concentrations that are used, there is a higher risk of toxicity. These potential reactions, while still rare, are better managed in a healthcare provider’s office instead of at the patient’s home. All compounded lidocaine 10% creams made by our pharmacy require a prescription. However the product can be shipped to the doctor’s office so that it can be used on the individual patient when they come into the office for their procedure.